JANUARY 1980

Gip

ciewd lope 0.

Fupeltlans

P I Inside4111

DEEPSPACEPROBESUniversal BuffeMoving Coil PreampKirlian Photography

... NEWS . . . . PROJECTS.. . MICROPROC';

ETIllii:k111/111

ISSN 0142 6192.4*

TRANSCENDENT 2000SINGLE BOARD SYNTHESIZER

LIVE PERFORMANCE SYNTHESIZER DESIGNED BY CONSULTANT TIM ORR (FORMERLY SYNTHESIZER DESIGNER FOR EMS LIMITED) AND FEATURED AS ACONSTRUCTIONAL ARTICLE IN ELECTRONICS TODAY INTERNATIONAL.The TRANSCENDENT 2000 is a 3 octave instrument transposable 2 octaves up or down giving an affective 7 octave range There is portamento. pitch bending.a VCO with shape and pitchmodulation. a VCF with both low and high pass outputs and a separate dynamic sweep control, a noise generator and an ADSR envelope shaper Thereis also a slow oscillator a new purrdetector. ADSR repeat. sample and hold, and special circuitry with precision components to ensure tuning stability amongst its many featuresThe kit includes fully finished metalwork, fully assembled solid teakcabinet, filter sweep pedal, professional quality components (allresistors either 2% metal oxide or V:r ':Yr metal trim') and it really iscomplete - right down to the last nut and bolt and last piece of wire,There is even a 13A plug in the kit - you need buy absolutely no moreparts before plugging in and making great music, Virtually all thecomponents are on the one professional quality fibreglass PCB printedwith component locations All the controls mount directly on the mainboard all connections to the hoard are made with connector plugs andconstruction is so simple it can be built easily in a few evenings byalmost anyone capable of neat soldenngi When finished you willpossess a synthesizer comparable in performance and quality withready -built units selling for between £500 and £700,

COMPLETE KITONLY

£168.50 + VAT!Comprehensive handbook supplied with all complete kitsi Thisfully describes construction and tells you how to set up yoursynthesizer with nothing more elaborate than a multi -meter and apair of ears'

WE'VE MOVED!NEW FACTORY UP!

PRICES DOWN!

OSCILLATOR VCO

Cabinet size 24.6" x 15.7" x 4.8" (rear) 3.4" (front)

ENVELOPE

INCREASED CAPACITY AT OUR BIG NEW FACTORYMEANS MANY PRICES' DOWN! ALL OTHERS FROZEN!

TRANSCENDENT DPXDIGITALLY CONTROLLED, TOUCH SENSITIVE, POLYPHONIC, MULTI -VOICE SYNTHESIZER

The Transcendent DPX is a really versatile new 5 octave keyboard instrument There are two audio outputs which , ri mi,reed sound - fully polyphonic e you can play chords with as many notes as you like On the second output there is c wide range 01 ilitlereni vim es sliii icilypieriiii I I arra 1,0straightforward piano or a honky took piano or even a mixture of the two' Alternatively you can play strings over the whole range of the keyboard or brass over the whole range of thekeyboard or should you prefer - strings on the top of the keyboard and brass at the lower end (the keyboard is electronically split after the first two octaves) or vice versa or even acombination of strings and brass sounds simultaneously And on all voices you can switch in circuitry to make the keyboard touch sensitive, The harder you press down a key the louder itsounds Just like an acoustic piano The digitally controlled multiplexed system makes practical touch sensitivity with the complex dynamics law necessary for a high degree ofrealismThere is a master volume and tone control a separate control for the brass sounds and also a vibrato circuit with variable depth control togetherwith a variable delay control so that thin vibratocomes in only after waking a short time after the note is struck for even more realistic string sounds

Cabinet size 36.3" x 15.0" x 5.0" (rear) 3.3" (front)

COMPLETE KIT ONLY E299.00 + VAT!

systent00,posarri err

s Isisreln, d iretal r rmiry deptir rlittir can be isisily taken iv are: trot,err I and an interim, socket 125 wok D type) us provided for this pr

r orrIpater (for strearrj and play rig bar k Orlipiireer 0r y,,10 Of wiitiir,ut per n rr n..yifirmrooSe

cool .1

mu.. the DPX advanced design trsarig a very large arnOrrnt of cur Luny mut of it eery sophisticated the kit is nier harccolly extremely simple wuh PE 0110r, (II rPS, in all Er,.' r

E 100,0 nonact with multiway connectors lust four of which are reranved :0 separate the keyboard circuitry and the pane, ircultiy trout the main car rat, in tine atEre

ml .':rides fully Iinisiiird metalwork solid teak cabinet professional quality components tall reresrprs 2 metal oxide) nuts bolts etc even a 134 plug - you rifted buy absiii iti lr;tarts before plugging in and making grect muse' When finished you will possess an instrarent comparable in perforn,er 0 and nullity with ready Mug unit, selling for over I 1 212'

POWERTRANORDERING INFORMATIONAND MORE KITS ON PAGE E

kits also available as Separate pack,P C B component sets. hardware sets etc

Prices in FREE CATAI.OGUE

on the front p.56

step up to coils p.29

electrolg NayJANUARY 1980 VOL 9 NO 1 INTERNATIONAL

FEATURESDIGEST

KIRLIAN PHOTOGRAPHYDESIGNERS NOTEBOOK

ELECTRONICS IN THE STUDIOINDEX 79

MICROFILEAUDIOPHILE

DEEP SPACE PROBESSPEAKER DESIGN PROPOSAL

TECH TIPS

9 All that's worth knowing22 Electric picture show37 A look at the 409349 Join the professionals62 A vintage ETI year67 BASIC language war76 Gold ring goodies86 Voyaging Viking Pioneers95 New sound ideas101 Ideas from Readerland

PROJECTSMOVING COIL CARTRIDGE PREAMP 29 A moving experience for your amplifier

EPROM PROGRAMMER 42 Teach your chips a thing or twoDIGITAL FREQUENCY METER 56 Count your blessings

PROCESS CONTROLLER 71 In the mean -time . . .

AUDIO INPUT BUFFER 82 Match -making made easy

INFORMATIONSEIKO WATCH OFFER

FEBRUARY ETIBOOKS

ETIPRINTSBACK NOS.

SPECIALSCT CARRYOVERMARKETPLACE

BINDERSHOBBY NEXT MONTH

10 Luxury wrist wear26 Our monthly preview46 Some light reading54 Professional board page64 Fill the spaces on your bookshelf65 Top projects and much more89 The future of computing74 Armchair shopping92 Hardback your mags.110 February in HE

INTERNATIONALEDITIONS

AUSTRALIA Collyn RiversPublisherRoger HarrisonActing Editor

Anton KriegsmanEditor -in -Chief

HOLLAND

CANADA

GERMANY

Graham WidemanEditor

Udo WittigEditor

ABC

EDITORIAL AND ADVERTISEMENT OFFICE145 Charing Cross Road, London WC2H 8DEE. Telephone 01 437 1002/3/4/5

Ron Harris. B ScIan Graham B.Sc.Diego M. Rincon

Dee CamilleriPaul Edwards, Tony Strakas

Joanne BarseghianRay Marston

Keith Brindley, John FitzgeraldSteve Rams a hadeo

Margaret HewittLorraine Stout

Christopher Surgenor (Manager)Sandie Neville

Steve RoweHalvor Moorshead

EditorEditorial AssistantArt DirectorProductionTechnical Illustrators

Project EditorProject EngineerProject DevelopmentAdministrationEditorial SecretaryAdvertisingAd. ProductionAd. RepresentativeEditorial Director

PUBLISHED BYDISTRIBUTED BY

PRINTED BY

Modmags Ltd.. 145 Charing Cross RoadArgus Distribution Ltd (British IslesiGordon & Gotch Ltd , ,,s.

QB Limited, Colchester

Electronics Today International is normally published on the first Friday of the month prior to the cover date

COPYRIGHT: All material is subject to world wide Copyright protection. All reasonable care is taken in the preparation of the magazine to ensureaccuracy but ETI cannot be held responsible for it legally. Where errors do occur a correction will be published as soon as possible afterwards.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 3

1111-PAK SEMICONDUCTORSBOOKS BY BABANI OPTOELECTRONICS AUDIO LEADS

BP6 Engineers & Machinists Ref. TablesBP14 2nd Book Transistor Equivs & SubsBP24 52 Projects Using IC741 (or Equiv)BP26 Radio Antenna Book Long Distance

Reception & TransmissionBP27 Giant Chart of Radio Electronic

Semiconductor & Logic SymbolsBP32 Build Metal & Treasure LocatorsBP35 Handbook of IC Audio Preamplifier &

Power Amplifier ConstructionBP36 50 Cmts use Germ /SII /2ener DiodesBP39 50 field Effect Trans ProtectsBP40 Digital IC Equivs & Pin ConnectionBP41 Linear IC Equivs & Pin ConnectionBP42 50 Simple LED CircuitsBP43 How to make WalkieTalloesBP45 Projects on Optoelectronics8P46 Radio Circuits Using IC sBP47 Mobile Discotheque HandbookBP48 Electronics Projects for BeginnersBP49 Popular Electronic ProjectsBP50 IC LM3900 ProjectsBP55 Radio Stations GuideBP160 Cool Design & Construction ManualBP202 Handbook of Integrated Circuits

Equivalent & SubstitutesBP205 let Book 1-11.-Fi Speaker EnclosuresBP213 Circuits for Model RailwaysBP215 Shortwave Circuits & Gear for

Experimenters & Radio HamsBP21 7 Solid State Power Supply HandbookBP221 28 Tested Transistor ProjectsBP222 Shortwave Receivers for BeginnersBP223 50 Projects using IC CA3130BP224 50 CMOS IC ProjectsBP225 A Practical Intro to Digital IC'sBP226 Build Advanced Short-wave ReceiversBP227 Beginners Guide to Building

Electronic Projects

NEWNES BOOKS216 Tramistors 3rd Ed217 Integrated Circuits218 Radio & Television219 Electronics220 Colour TV 2nd Ed221 I-h-Fi

222 20 Solid State Prot for Car223 20 Solid State Proj for Home224 110 Int City Proj for Home225 110 Thyristor Projects226 Operational Amp Proj for Home228 Electricity229 Beginners Guide to Electronics230 Beginners Guide to Television231 Beginners Guide to Transistors232 Beginners Guide to Electric Wiring233 Beginners Guide to Radio234 Guide to Colour TV235 Electronic Diagrams236 Electronic Components237 Printed Circuit Assembly238 Transistor Pocket Book239 50 Photoelectric Circuits240 Semiconductor Handbook Part 1

241 Semiconductor Handbook Part 2242 Electronics Pocket Book244 Beginners Guide to Integrated Circuits209 81-PAK TTL Data Book

151.PAK CMOS Data Book

E0.50E1.10£0.95

£0.85

£0.60£1.00

E1.25£0.75£1.25E2.60£2.75£0.75£1.25£1.25£1.35E1.35E1.35£1.45£1.35£1.45E0.75

£1.00£0.75£1.00

£0.85£0.85£1.25£0.95£0.95f0.95E0.95E1.20

£1.25

£1 00£1.00E1.25E1.15E1.15E1.15£1.95£1.95£2.95E2.50E2.50E1.15E2.25E2.26E2.25E2.25E2.75£2.25£1.80E1.80£1.80E3.90£1.80E5.25E4.28E3.90£2.75

50p50p

NEW INCREASED RANGE - ALL 1ST DUALITYLED S (diffused)0/no. Type Sint1501 ARL209 M1209) 3mm ( 125)1502 MIL3232 (111211).3mm ( 125)1503 MIL3331 (0P212A) 3mm ( 12511504 ARI4850 (FLV117) 5mm 2)

1505 MIL5251 (T11222) 5mm(.2)1506 MIL5351 (MV5353).5mm) 2)1509 FLV111 5mm ( 2)

SUPER 'Hi -Brit.' Type1521 MtL32 .3mm (.125)1522 MIL52 .5mm(.2)1514 ORP12 Light dependent resistor1520 OCP71 Photo transistorLED CLIPS1508/125 pack of 5 125 clips1508/ 2 pack of 5 2 clips

ColourREDGREENYELLOWREDGREENYELLOWCLEAR(ill. Red)

REDRED

Price£0.12£0.22£0.22E0.12£0.22E0.22£0.13

£0.12£0.12£0.63E0A0

£0.17E0.21

DISPLAYS:DL703 7 segment D P left 1.30" height) Common AnodeRED Single Digit o/no. 1523 E0.85DL707 7 segment D P left I.30" height) Common AnodeRED Single Digit o/no. 1512 E0.92DL527 7 segment D P left ( 50" height) Common AnodeRED Two -Digit Reflector o/no. 1524 £2.0801.727 7 segment D P right (.510" height) Common AnodeRED Smoke Digit Light Pipe o/no. 1512 £2.0701.747 7 segment D P 1011(630" height) Common AnodeRED Single Digit Light Pipe o/no. 1511 1.1.73

OPTO-ISOLATORSIsolation Breakdown - Voltage 1500 - continuous fwd current 100mACIL74 Single -Channel 6 pin DIP standard type - optically coupled pan,with infra -red LED Emitter and NPN Silicon Photo Trensistor

o /no. 1497 E0.61CILD74 Multi -Channel 8 pin DIP Two Isolated Channels

o /no. 1498 E1.22CILD74 Multi -Channel 16 pin DIP Four Isolated Channels

o/no.1499 E2.69

MEL 11 (TIL81) NPN Light DetectorSilicon Photo Darlington Amplifier - VCI50 30v VECO 10v lc 100mAPtot 300mW IL Mtn 0 5 Typ 2mA ID 100mA nA £0.29

No. Type107 FM indoor Ribbon Aerial113 3 5mm Jack plug to 3.5mm Jack plug Length 1.5m114 5 pin DIN plug to 3 5mm Jack connected to pins

3 & 5 Length 1.5m115 5 pin DIN plug to 3.5mm Jack connected to pins

1 & 4. Length 1 5m116 Car aerial extension Screened insulated lead

Fitted plug and socket117 AC mains connecting lead for cassette recorders

and radios 2 metres118 5 pin DIN phono plug to stereo headphone

Jack socket119 2 2 pin DIN plugs to stereo Jack socket with

attenuation network for stereo headphonesLength 0 2m

120 Cm stereo connector Varmt.le geometry plug tofit most car cassettes. 8.track cartridge andcombination units Supplied with mimed fusepower lead and instructions

123 6 6m Coiled Guitar Lead Mono Jack plug to MonoJack plug Black

124 3 pin DIN plug to 3 pin DIN plug Length 1 5m125 5 pin DIN plug to 5 pin DIN plug Length 1 5m126 5 pin DIN plug to Tinned open end. Length 1.5m127 5 pm DIN plug to 4 Phone Plugs

All colour coded. Length 1 5m128 5 pin DIN plug to 5 pin DIN socket Length 1 5m129 5 pin DIN plug to 5 pin DIN plug mirror image

Length 1 5m130 2 pm DIN plug to 2 pin DIN inline socket.

Length 5m131 5 pin DIN plug to 3 pin DIN plug 1 & 4 and 3 & 5

Length 1.5m132 2 pin DIN plug to 2 pin DIN socket Length lOrn133 5 pin DIN plug to 2 Phono plugs

Connected pins 3 & 5 Length 1 5m134 5 pin DIN plug to 2 Phono sockets

Connected pins 3 & 5 Length 23cm136 5 pin DIN socket to 2 Phono plugs

Connected pins 3 & 5. Length 23cm136 Coiled stereo headphone extension lead

Black. length 6m178 AC mains lead for calculators etc

Price£0.69E0.86

£0.98

E0.98

El 44

E0.78

E1.21

E1.04

£0.69

£1.72E0.85CO 85E0.85

El 49E0.92

£1 21

£0.78

£0.95£1.13

E0.86

£0.78

£0.78

£2.01£0.52

SWITCHESDescriptionDPDT miniature skdeDPDT standard slideToggle switch SPST amp 250V acToggle switch DPDT 1 amp 250V acRotary on -off mains switchPush switch - Push to makePush switch - Push to break

ROCKER SWITCHA range of rockerswitches SPST - mouldedin high insulationmaterial available in achoice of colours idealfor small apparatus

No.1973197419751976197719781979

ColourREDBLACKWHITEBLUEYELLOWLUMINOUS

Description No.Miniature SPST toggle 2 amp 250V ac 1958Miniature SPST toggle 2 amp 250V ac 1959Miniature DPDT toggle 2 amp 250V ac 1960Miniature DPDT toggle centre oft 2 amp

250V ac 1961Pushbutton SPST 2 amp 250V ac 1962Push-button SPST 2 amp 250V ac 1963Pushbutton DPDT 2 amp 250V ac 1964

No.198019811982198319841985

Price£0.16f0.17£0.36£0.45£0.56£0.16£0.21

Price£0.35£0.35£0.35£0.35£0.35£0.35

Price£0.81£0.86£0.91

£1.07E1.04£1.09£1.34

MIDGET WAFER SWITCHESSingle bank wafer type - suitable for switching al 250V at 100mA or150V dc in non -reactive loads make.beforebreak contacts Theseswitches have a spindle 0 25.n die and 30 indexing

Description1 pole2 pole3 pole4 pole

12 way6 way4 way3 way

No.1965196619671968

MICRO SWITCHES No.Plastic button gives simple 1 pole change over actionRating 10 amp 250V ac 1970

Price£0.55£0.55£0.55£0.55

Price

E0.29

FUSE HOLDERS AND FUSES

Description No. Price20mrn x 5mm chassis mounting 506 £0.181Vonx 1/41n chassis mounting 507 E0.14l'Ain car mime type 508 E0.18Panel mounting 20mm 509 E0.23Panel mounttng l'Ain 510 E0.37

QUICK BLOW 20rnatType No. Type No. Type No15OrnA 611 7p IA 615 13p 3A 619250mA 612 Bp 1 5A 616 7p 4A 62055OrnA 613 Sp 2A 617 Bp 5A 621800rnA 614 Bp 2 5A 618 7p

ANTIS URGE 2OrtonType No. Type No. ' Type No.10OrnA 622 1A 625 2 5A 626250mA 623 2A 626 3 15A 629500mA 624 1 6A 627 5A 630

/UI Bp each .QUICK -BLOW 11/4inType No. Type No. Type No.

25OrnA 631 500mA 632 800mA 634All Bp each

Type No. Type Na. Type No.lA 635 2 5A 638 4A 64126 637 3A 639 54 642

All Bp each

NUTS AND BOLTS

6010p

6p

BA BOLTS - packs of BA threaded cadmium plated screws slottedcheese head Supplied in multiples of 50Type No. Price Type No. Pricetin OBA 839 £1.39 h., 4BA 846 £0.37` ).11 OBA 840 1E0.86 in 4BA 847 E0.29lm 2BA 842 £0.76 1in6BA 048 £0.461/2in 2BA 843 £0.52 '/tin 68A 849 E0.241/4m 2BA 844 1E0.60 .in 68A 850 £0.29tin 4BA 845 £0.51

BA NUTS -- packs of cadmium plated full nuts in multiples of 50Type No. Price Type No. Price060 855 £0.83 ABA 857 £0.352134 856 £0.55 6BA 858 £0.28

BA WASHERS - flat cadmium plated plain stamped washers suppliedmultiples1114 Of 50

Type No. Price Type No. PriceOBA 859 £0.16 486 861 £0.14/8. 860 £0.14 68A 862 £0.14

SOLDER TAGS - Hot tinned supplied in multiples of 50Type No. Price Type No. Price0134. BSI E0.46 48A 853 £0.25260 852 E0.32 6BA 854 £0.25

TANTALUM31373138313931403141

1MFD 35V E0.1322MFD 35V £0.1347MF0 35V £0.131 OMFD 35V £0.132 2MFD 35V E0.14

CASES AND BOXESINSTRUMENT CASES. In two secoons vinyl covered topaluminium bottom. front and back

No. Length Width Height51/2 in 2inbin 3m41Atin 114m534In 2'hin

155 Bin156 lltn157 6in158

and side

PriceE1.73E2.92E1.79£2.43

ALUMINIUM BOXES. Made from bright all . folded construction eachbox complete with half -inch -deep lid and screws.

No. Length Width Height159 51/4in 2 1/4 tn 11/2m

160 4in 4in 11/2in161 bin 21/4 in libin162 5%in 4in 11/2 in

163 4in 21/21n

164 3m 210165 Tin Sin166 8tn 6on

6in 4in

2in1m21/2m

Price£0.85E0.85£0.85E0.97£0.87£0.60E1.43£1.82£0.18

TRANSFORMERSMINIATURE MAINS Pnmary 210VNo. Secondary2021 6V46V 100mA2022 9V -0-9V 100mA2023 12V0 -12V 100mAMINIATURE MAINS Primary 240Vwith two independent secondary windingsNo Type Price

024 MT280-0-6V 0-6V RMS £1.842025 MT150-0-12V 0-12V RMS £1.84

1 AMP MAINS Primary 240VNo Secondary Price2026 6V -0-6V 1 amp E2.88 P & P 45p2027 9V -0-9V 1 amp £2.30 P & P 45p2028 12V.0.12V 1 amp E2.99 P & P 55p2029 15V.0.15V 1 amp E3.16 P & P 66p2030 30V.0 -30V 1 amp E3.97 P & P 86p

STANDARD MAINS Primary 240VMuletapped secondary mains transformers available in '/, amp. 1 amp.trid 2 amp current rating Secondary taps are 0.19.25.33.40.50VVoltages available by use of taps4 7 8 10 14 15 17 19. 25. 31 33.40 25-0.25VNo Rating Price:031 1/2 amp E3.91 P &P 86p2032 I amp E5.06 P &P 86p2033 2amp E6.27 P &P (1

PriceC1.04El .04E1.29

2035 240V Primary0-55V (iD2A Secondary E7.30 P &P I1

SPECIAL OFFER2042 240V Primary O -20V (Al 2A Secondary By removing 5 turns foreach volt from the secondary winding any voltage up to 20V @ 2A isaasily obtainable Ideal for the experimenter

E1.50 0 &P 86p

CAPACITORS HEATSINKS

31423157314331443156

4 4MFD 35V £0.213 3MFD 25V £0.2110MFD 35V £0.2522MFD 16V £0.7533MFD 35V £0.13

TypeT03 - single heat sink703 - double heat sinkDouble sided heat sink705 39 heat sink7018 - heat sinkTO I - heat sink

No873874875876877878

Rice£0.31£1.38f1.67£0.16£0.14£0.09

Terms cash with order. Cheques/Postal Oilers made payable to Bi-Pak at hove address

4 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

1

Send your orders to:-DEPT ETI 11, PO BOX 6 , WARE, HERTS. Tel 0920-3182Visit our NEW shop: 3 BALDOCK ST., WARE HERTS. Telex: 817861

EXPERIMENTOR BREADBOARDS FROM MOM

No soldering modular breadboards, simply plug componentsin and out of letter numbec identifiednickel -silver contact holes. Start small and simplysnap -lock boards together to build breadboard of any size.All EXP Breadboards have two bus -bars as an integral part ofthe board, if you need more than 2 busessimply snap on 4 more bus -bars with the aid of an EXP.413.

EXP.325. The ideal breadboard for1 chip circuits.Accepts 8, 14, 16 and up to 22 pin IC's.

ONLY £1.71

EXP.350 £3.62270 contact points withtwo 40 -point bus -bars

EXP.300.550 con-tacts withtwo 40point bus -bars

£6.61

EXP.650for Micro-processors

£4.14

1111

ifill 11111111111111111111111111111111111111

'1111111111111111111111111

'1111111111111111'

EXP.4BMore bus -bars, met teeee met 11111 11111 11111 steel 11111 I

£2.65 :nu 11111 11111 stele :este 11111 11111

ALL EXP 300 Breadboards mix and match with 600 series.

THYRISTORS600me TO 18 CaseVolts No

10 THY600 1020 THY600 2030 71-10600 -3050 TH1600750

100 THY600 ' 100200 1310600:200400 THY600 400

Price£0.17£0.18£0.23f0.25£0.29£0.44£0.51

1 amp TO 66 CaseVolts No Price

50 THY1A 50 £0.30100 t0014 100 £0.32200 THY1A 200 £0.37400 THY I A 400 £0.44600 THY IA 600 £0.52800 111014 800 £0.67

3 amp TO 66 CaseVolts Na Price

50 THY34 50 £0.32100 THY34 100 £0.35200 11034 200 £0.38400 TH034 400 £0.48600 THY34 600 E0.5880010134 800 £0.75

5 amp TO 66 CaseVolts No Price

50 831054 50 E0.41IOC 113054. 100 £0.52200 TH054 200 £0.58400 TH' 5A 400 50.88600 THY5A 600 £0.79800 10054 800 E0.93

5 amp TO 220 CeseVohs No Price400 01554 4008 £0.86600 THY5A 600P £0.79800 THY5A 800P £0.93

7 amp TO 48 CawVolts No

50 1/1074 50 £0.55100 TH074 100 £0.59200 THY 7A 700 EOM400 THY 7A 400 £0.71600 70074 .600 £0.90800 THY7A 800 £1.06

10 amp TOW Ca.Volts No Pecs

50 TH0104 50 £0.59100 71710104 100 £0.98700 1110104. 200 £0.71400 1110104 400 £0.81600 THY10A 600 E1.14800 THY10A 800 £1.40

16 amp TO 48 Casevolts No Price50 TI -10164 50

100 10016A 100700 THY164 200400 71-10164. 400600 THY16A 600800 00016.4 800

[0.62E0.67£0.71£0.89Cl .04E1.60

30 amp TP 94 CassVolts No Prone

50 160304 50 E1.36100 18030.4 100 E1.64200 080304 200 E1.87400 TH-1304 400 £2.06600 THY 304 600 E4.03

NoBT101 500R87107 5008BT106BT107BT1087N32287N352500(30 501131 V30 4001C106 491116

SPECIAL OFFERS

Price£0.92£0.92£1.44£1.07E1.13£0.81E0.89£0.38£0.53£0.69E1.73

MINIDRILL 12v hand held battery -operated mini drill7 500 r p m Collet chuck ideal for drilling printed circuits ormodel making NO 1002 £7.79TRANSFORMER 240v Primary 0-20v @24 SecondaryBy ter -nova -1g 5 turns for each volt from the secondarywinding any voltage up to 20v @,24 is obtainable ideal forthe experimenter No 2042 £1.50+86p P & PANTEX MLX soldering iron Sturdy 25 watt iron completewith 4',2 metres of 2 -core Works off a 12 volt battery Idealfor car Boat. Caravan No 1 724 £5.29

POTENTIOMETERSCARBON POTS (Linear Track)Single gang with wire end terminations,6mm x 50mm plastic shaft 10mmbushes supplied with shake proof washerand nut. Tolerance 20% of resistance

1839 1 k ohms1832 2k2 ohms1833 4k7 ohms1834 10k ohms1835 22k ohms1836 47k ohms

1837 100k ohms1838 220k ohms1839 470k ohms1840 1 Meg1841 2M2All at 30p each

CARBON POTS (Log Track)1842 4k7 ohms 1847 220k ohms1843 10k ohms 1848 470k ohms1844 22k ohms 1849 1 Meg1845 47k ohms 1850 2 M21846 100k ohms All at 30p each

Designed to fit 2 54mm pitch board Alltracks are linear law.VC71816 100 ohms 1824 47k ohms1817 220 ohms 1825 100k ohms1818 470 ohms 1826 220k ohms1819 1k ohms 1827 470k ohms1820 2k2 ohms 1828 1 Meg ohms1821 4k7 ohms 1829 2M2 ohms1822 10k ohms 1830 4M7 ohms1823 22k ohms All at 10p each

DUAL CARBON POTS (Log Law)1860 4k7 ohms 1865 220k ohms1861 10k ohms 1866 470k ohms1862 22k ohms 1 867 1 Meg1863 47k ohms 18682M21864 100k ohms All at 99p each

SINGLE GANG SWITCHED (Lin Law)These potentiometers are fitted withdouble pole on -oft switches. The switch isincorporated within the rotary action ofthe pot. Specification of pot is as VCISwitch rating 1 5 amps at 250v AC1870 4k7 ohms 1875 220k ohms1871 10k ohms 1876 470k ohms1872 22k ohms 1877 1 Meg1873 47k ohms 1878 2M21874 100k ohms All at 75p each

DUAL GANG LONG -ANTI -LOG POT1888 Track specification as dual gangpots VC3. but tracks mounted to loyVi-log action 100k ohms E0 86

SPECIAL VOLUME CONTROLSA miniature 16mm type replacementvolume control. incorporating single poleon -oft switch Resistance value 5k ohms.Tolerance t 20% 1/8 watt rating1889 E0.31 VC8MINIATURE ROTARY VOLUMECONTROL5k ohms log law with on -off switch20mm grooved spindle. Tag connections17mm dia. Supplied with fixing nut Usedmainly for replacement.1890 £0.62 VC9

WIRE WOUND POTSA range of wire wound single gang potswith linear tracks of 1 watt rating, fittedwith 10mm bush and supplied withshakeproof washer and nutVC61891 10 ohms 1896 470 ohms1892 22 ohms 1897 1k ohms1893 47 ohms 1898 2k2 ohms1894 20 ohms 1899 4k 7 ohms1895 220 ohms All at 92p eachSWITCHED POT (Log Track)Specification as VC2 but track having (log)taw1879 4k7 ohms 1884 220k ohms1880 10k ohms 1885 470k ohms1881 22k ohms 1886 1 Meg1882 47k ohms 1887 2M 21883 100k ohms All at 75p each

Prrr.-SET POTSHORIZONTAL MOUNTINGMiniature type for transistor circuits Toewiper of the preset is provided with a slotfor screw driver adjustment The tags ofthe preset will fit printed wiring boardswith a pitch of 2 54mm All tracks arelinear lawVC71801 100 ohms 1809 47k ohms1802 220 ohms 1810 100k ohms1803 470 ohms 1881 220k ohms1804 IV ohms 1812 470k ohms1805 2k2 ohms 1 81 3 I M ohms1806 4k7 ohms 1814 2M2 ohms1807 10k ohms 1815 4M7 ohms1808 22k ohms All at 10p eachPRE-SET POTSVERTICAL MOUNTINGMiniature type for transistor circuitsWiper adjustment is made by a screwdriver slot

ANTEX IRONS1943 15 watt high quality soldering irontotally enclosed element in a ceramic shaftfitted with 3/32 bit. E4.831947 Replacement element for 1943iron E2.191944 iron coated bit 3/32"for 1943iron £0.531945 iron coated bit Va" for 1943 iron

£0.531946 iron coated bit 3/16" for 1943iron £0.531948 General purpose 18 watt iron fittedwith iron coated bit £4.541952 Replacement element for 1948iron. £2.191949 iron coated bit 3/32" for 1948

iron E0.531950 iron coated bit Ye" for 1948 iron

£0.531951 iron coated bit 3/16" for 1948iron E13.531931 Highly popular .25 25 watt qualitysoldering iron ceramic shafts to providenear perfect insulation breakdown voltage

AmplifiersALZD

141364

AL60

ALSO

ALI 20

61250

Pre -amplifiersPA12

PAIDO

P62000

5 watt amplifier module7-10 watt amplifier module15-25 watt amplifier module35 watt amplifier module50 watt amplifier module125 watt Amplifier module

Stereo pre -amplifier moduleStereo pre amplifier matureStereo pre -amplifier module

of 1500 volts AC and a leakage current ofonly 3-5uA and another shaft of stainlesssteel to ensure strength £4.831935 Replacement element for 1 931iron £1.841932 iron coated bit 1/4" for 1931 eon

£0.581933 iron coated bit 2 / 16" for 1931iron £0.581934 iron coated bit 3$ 32" for 1 931iron £0.581953 SKI soldering kit - This kit con.tains 15 watt soldering iron fitted with a3/16" bit plus two spare bits a reel ofsolder. heat -sink and a booklet How tosolder In presentation display box

£6.381939 ST3 soldering iron stand Standmade from high grade bakelite material.chromium plated strong steel sprang,suitable for all models. includes accom-modation for six spare bits and twosponges which serve to keep the solderingiron bits clean. E1.73

AUDIO MODULES

E3.73E4.35

E5.39E8.44

E13.74E19.24

E8.94E18.45E19.07

Power SuppliesPSI2SPM80SPM 120:45

SPM120/55SPMI20'65SC30

MiscellaneousMPA30

5450Stereo 30

8P124

6E10081811

Access & Barclaycard accepted. Giro a/c no. 38E11006. All prices include VAT.

Add 35p postage per order

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

SILICONRECTIFIERS

20OrnA15920 50v15921 100v35922 150v,5923 200v6924 3000

I Amp.54001 50vN4002 100vN4003 200vN4004 400v54005600v54006800vN4007 1000v

1.5 Amp,=:115 50v15020 100v15021 200v15073 400v15075 600v'5027 800v,S029 1000v15031 1200v

3 Amp315400 50vN5401 100vN5402 200v55405 400vN 5406 600vN5407 800vN5406 1000v

10 Amp510.'50 50v510 100 100v510 200200v510 '400400v5107600600v510-800 800v510710001000v5in 1200 1200v

AVIV50 50v

b 30 1(10100v.S30,200 200v530. 400 400v

1530)600600v1530 800 800v1630 1000 1000v530 1200 1200V

70 Amp570 5050.'570 100 1000I5707200 200v570 400400v1,.70 600 600v370 '800 800v570 10001000v00038 300 64 300v80X38 600 6A 600,80038 '300 Rev 6A 300v800387600 Rev 64 600v

2ENER DIODES

£0.07£0.07(0.08(0.09E0.10(0.12

E0.051/2(0.06£0.0703.08(0 09£0.10£0.12

0.10£0.1200.13(0.15£0.16£0.18£0.23£0.29

CO 16£0 .17£0 .18C0.22C0.24CO 29£0.35

(0 22E0.24£0.26£0.40E0 48E0.59£0.69£0.79

£0 84(0.79E1.07£1.44E202£2.23£2.51£3.16

(0.88£0.97£1 38(2.01£2 59(2 88E3 45£0 52£069£0.52£0.69

400 trw 113488l 0007 Glass entabsulated range of voltages available1 3v 2 2v 2 7v 3 3v 3 9v 4 3v4 70 5 to. 5 6v 6 2v 6 80 7 5v8 2v 9 lit 10v I lv 12v 13v 15v16v 18v 70v 72v 240 27v '10,33v 39v

No. 24 fp each

le 1 5no Plastic *and rneie1 encepsolaced Range of voltages evadatrieI 3v 2 2v 2 7v 3 3v 3 9v 4 3,4 7v 5 Iv 5 6v 6 2v 6 8v 7 sv820 910 10v Ilv 12v 13v 15v160 18v 20v 77v 24v 270 30v33v 430 47v 51v 68v 77v 75v82v 91v 100v

No. 213 17p leech

10w Metal stud type S010 caseRange of volidges evaiieble 1 1,2 2v 2 7v 3 3v 3 9v 4 3v 4 by5 lv 56v 62v 68v 75v 8109 to 10v Ilv 17v 13v 15v 16v18v 209 22v 24v 270 30v 33v430 47v 51v 68v 72v 75v 82v91v I ilitv

No 210 40p each

Power supply 124 volts DC)Stabilised power supply (3301Stabilised power supply 14501Stabilised power supply 15501Stabilised power supply (550)Nyder supply equaliser

Stereo magnetic cartridge pre ampStereo laterGomplele 7 watt 4 stereoamplifier boardSiren alarm module 5 watts10 channel monographic equaliser

El 72£5.06E6.67E6.67E6.67E4.37

E4.42E26.72

E22.66E4.02

E23.00

Simply ahead . .ILPS NEW GENERATION OF HIGH

I.L.P. modular units comprisefive power amplifiers,pre -amp which iscompatible with thewhole range, and thenecessary powersupply units. Theamplifiers are housedand sealed withinheatsinks all of whichwill stand up toprolonged workingunder maximumoperating conditions.

With I.L.P. performance standards andquality already so well established,

any advances in I.L.P. design arebound to be of outstanding importance

- and this is exactly what wehave achieved in our new

generation of modularunits. I.L.P. professionaldesign principles remain

- the completelyadequate heatsinks,

protected sealed circuitry,rugged construction

and excellent performance.These have stood the

test of time far longerthan normallyexpected from

ordinary commercialmodules. So we have

concentrated onimprovements whereby our

products will meet evenmore stringent demands

such, for example, asthose revealed by vastly

improved pick-ups, tuners,loudspeakers, etc., all of

which can prove merciless toan indifferent amplifier system.

I.L.P. modules are for laboratory andother specialised applications too.

PRODUCTS OF THE WORLD'S FOREMOST SPECIALISTSIN ELECTRONIC MODULAR DESIGN

ELECTRONICS TODAY INTERNATIONAL - JANUARY 198C

and staying therePERFORMANCE MODULAR UNITSHY5 PRE -AMPLIFIER

VALUES OF COMPONENTS FOR CONNECTING TO HY5Volume - 10K log.Bass/Treble - 100K _et linear. Balance - 5K n. linear.

The HY5 pre -amp is compatible withall I.L.P. amplifiers and P.S.U.'s. It iscontained within a single pack 50 x40 x 15 mm. and provides multi-function equalisation for Magnetic/Ceramic/Tuner/Mic and Aux (Tape)inputs, all with high overload margins.Active tone control circuits; 500 mVout. Distortion at 1KHz-0.01%.Special strips are provided for connec-ting external pots and switchingsystems as required, Two HY5'sconnect easily in stereo. With easy tofollow instructions.

£4.64 + 74p VAT

THE POWER AMPLIFIERSF.1KHzLOAD' Etn. ON ALLEXCEPT HY400 AT 4n. I

START OF WAVEFORM CUPPING /

/

I

5 io ioOUTPUT POWER -WATTS RIAS

50 100

THE POWER SUPPLY UNITS

I.L.P. Power Supply Units aredesigned specifically for usewith our power amplifiers andare in two basic forms - onewith circuit panel mounted onconventionally styled trans-former, the other with toroidaltransformer, having half theweight and height of con-ventional laminated types.

ModelOutputPowerR.M.S.

Dis-tortionTypicalat 1KHz

MinimumSignal/NoiseRatio

PowerSupplyVoltage

Sizein mm

Weightin gms

Price +V.A.T.

HY30 15 W 0.02% 80dB -20 -0-+20 105x50x25 155 £6.34into 8 CI + 95P

HY50 30 W 0.02% 90dB -25 -0 +25 105x50x25 155 £7.24into 8 St +E1.09

HY120 60 W 0.01% 100dB -35 -0-+35 114x50x85 575 £15.20into 8 2 + £2.28

HY200 120 W 0.01% 100dB -45 -0-+45 114x50x85 575 £18.44into 8 2 + £2.77

HY400 240 W 0.01% 100dB -45 -0-+45 114x100x85 1.15Kg £27.68into 4 S-2 + £4.15

Load impedance - all models 4 - 16n -Input sensitivity - all models 500 mVInput impedance - all models 100K -n -Frequency response - all models 10Hz - 45Hz - 3dB

PSU 30

PSU 36PSU 50PSU 70

PSU 90

PSU180

±15V at 100ma to drive up tofive HY5 pre -amps £4.50 + £0.68 VATfor 1 or 2 HY30's £8.10 + £1.22 VATfor 1 or 2 HY50's £8.10 + £1.22 VATwith toroidal transformer for 1 or2 HY120's £13.61 + £2.04 VATwith toroidal transformer for1 HY200 £13.61 +£2.04 VATwith toroidal transformer for1 HY400 or 2 x HY200

£23.02 + £3.45 VAT

* ALL U.K. ORDERS DESPATCHED POST PAIDHOW TO ORDER, USING FREEPOST SYSTEMSimply fill in order coupon with payment orcredit card instructions. Post to address asbelow but do not stamp envelope - we paypostage on all letters sent to us by readers ofthis journal.

III2ELECTRONICS LTD.FREEPOST 4 Graham Bell House, Roper Close,Canterbury, Kent CT2 7EP.Telephone 102271 54778 Telex 965780

1

Please supply

Total purchase price £

I enclose Cheque El Postal Orders 0 International Money Order D

Please debit my Account/Barclaycard Account No.

NO QUIBBLE5 YEAR GUARANTEE

7 -DAY DESPATCH ONALL ORDERS

INTEGRALHEATSINKS

BRITISH DESIGN ANDMANUFACTURE

FREEPOST SERVICE-SQQ below

NAME

ADDRESS

Signature

AMMON MO =I MN MIIIELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

I

I

7

CHROMATHEQUE 5000 pgrollmN5 CHANNEL LIGHTING

EFFECTS SYSTEMCOMPLETE KIT

ONLY

£49.50 + VAT!Panel size 19.0" x 3.5". Depth 7.3"

This versatile system featured as a constructional article in ELECTRONICS TODAY INTERNATIONAL has 5 frequency channels with individual level controls on each channel Control of thelights is comprehensive to say the least You can run the unit as a straightforward sound -to -light or have it strobe all the lightsat a speed dependent upon music level or front panel controlor use the internal digital circuitry which produces some superb random and sequencing effects. Each channel handles up to 500W and as the kit isa single board design wiring is minimaland construction very straightforward.

Kit includes fully finished metalwork, fibreglass PCB controls wire. etc - Complete naht down to the last nut and bolt'

MPA 200 100 WATT (rms into 80) MIXER/AMPLIFIERCOMPLETE KIT

ONLY

£49.90 + VAT!MATCHES THE

CHROMATHEQUE 5000

0- INTERNATIONAI -- -LI MA 1200 - .: -....:

0 MERIN

110

- ''''s., ss7,, s7:,, sT,,

:110.: ..: -.: s: .*: .,40:. 4.) 0 0 0 .

PERFECTLY! Panel size 19.0" s 3.5". Depth 7.3"Featured as a constructional article in ETI, the MPA 200 is an exceptionally low priced - but professionally finished - general purpose high power amplifier. It features adaptable inputmixer which accepts a wider range of sources such as microphone, guitar, etc. There are wide range tone controls and a master volume control. Mechanically the MPA 2000 is simplicityitself with minimal wiring needed making construction very straightforwardThe kit includes fully finished metalwork, fibreglass PCBs, controls. wire, etc - complete down to the last nut and bolt.

DE LUXE EASY TO BUILD LINSLEY HOOD75W STEREO AMPLIFIER £99.30This easy to build version of our world-wide acclaimed 75W amplifier kit based upon circuitboards interconnected with gold plated contacts resulting in minimal wiring and constructiondelightfully straightforward. The design was published in H-Fi News and Record Review andfeatures include rumble filter, variable scratch filter, versatile tone controls and tapemonitonng whilst distortion is less than 0.01%.

WIRELESS WORLD FM TUNER £70.20 + VATA pre -aligned front-end module makes this Wireless World published design very simple toconstruct and adjust without special instruments. Features include an excellent a.m. rejectionpush-button station selection as well as infinitely variable tuning and a phase locked loopstereo decoder, incorporating active filters for suppression

LINSLEY-HOOD CASSETTE DECK £79.60 +VATThis design, published in VVireless World. although straightforward and relatively low costprovides a very high standard of performance. There are separate record and replay amplifiersand switchable equalisation together with a choice of bias levels are also provided. Themechanism is the Goldring-Lenco CRV with electronic speed control.

T20+20 20W STEREO AMPLIFIER £33.10+VATThis kit, based upon a design published in Practical Wireless, uses a single printed circuitboard and offers at very low cost, ease of construction and all the normal facilities found onquality amplifiers. A 30 watt version of this kit (T30+ 30) is also available for E38.40 + VAT.

MATCHING TUNERS - SEE OUR FREE CATALOGUE'COMPLETE KITS: Our complete kits really are complete. All of the projects shown on this page are supplied with fully finished metalwork, ready assembled high quality teak veneer cabinet (last4 kits on this page), or professional quality rack mounting cabinet (first 2 kits on this page), cables, nuts, bolts, etc., and full instructions - in fact everything'

All of the kits shown on this page are available as separate packs for those customers who wish to spread their purchase or perhaps make their own cabinets or metalwork. Prices are given in ourFREE CATALOGUE.

PRICE STABILITY: Order with confidence. Irrespective of any price changes wewill honour all prices in this advertisement until February 28th. 1980, if this monthsadvertisement is mentioned with your order. Errors and VAT rate changes excluded

EXPORT ORDERS: No VAT Postage charged at actual cost plus 50p handlingand documentationU.K. ORDERS. Subject to 15% surcharge for VAT No charge is made forcarriage or at current rate if changedSECURICOR DELIVERY: For this optional service IU K mainland only) add£2 50 (VAT inclusive) per kitSALES COUNTER: If you prefer to collect kit from the factory call at SalesCounter Open 9 a m -4 30 p m MondayThursday

NEW FACTORY ON SAME INDUSTRIAL ESTATEADDRESS AND PHONE NUMBER UNCHANGED

OUR CATALOGUE IS FREE! WRITE OR PHONE NOW!

POWERTRAN ELECTRONICSPORTWAY INDUSTRIAL ESTATE ANDOVERANDOVER, HANTS SP10 3NM (STD 0264) 64455

8 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

DIGEST

/fgt.M!!It

NEWS

Blonde

Bombshell

Now be honest with yourself -aren't there times during thoselong cold winter days whenyou could do with one of thesein your office. No, unfortun-ately I don't mean Blondie inthe white pants. The blondebombshells here are thebrushed aluminium boxes ofITT Terryphone's new solidstate intercom units.

The intercom, which doublesas a security and alarm system,consists of a master unit andfrom one to nine sub -units. Thesystem is easily installed inmany configurations.

Simple press -button -to -talkoperation is featured on themaster and sub -units. Each'sub -unit can be called indepen-dently from the master unit, orall sub -units can be calledsimultaneously. Pressing theself -latching security buttonallows noises from children,equipment, burglars, etc to bepicked up and transmitted toother parts of the premises. So,the intercom can be used as asecurity system in smallbusinesses of a baby alarm athome.

Each sub -unit comes com-plete with cable and cablefixing pads for £20 each. Themaster unit costs £85 andcomes with a mains plug and ascrewdriver. Talking of Blondie- she can install an intercom inmy office any time.

Further details of this systemis available from ITT Ter-ryphone, Station Approach,London Road, Bicester, OxonOX6 7BZ.

Near ThingIf you find yourself in one ofthose situations where youneed to know how near theknuckle something is, armyourself wiith a proximityswitch.

The Omron TL series fromIMO Precision Controls is aseries of low cost, inductive,proximity switches, which nowincludes AC operation types

TL-XY 5mm and 10mm andTL -YS 10mm. All examples ofthe series offer reliable sensingof ferrous material. Flush -mounting and flat -mountingtypes are available. All theswitches are available fromstock and typical prices to theOEM would be under £20.

You can get further details ofthe Omron TL series from IMOPrecision Controls Ltd, 349Edgware Road, London W2IBS.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

AMORY-1.3.,LENDAA

tT e 969 19 19 t9 IMS

RAVK

SEIKOcx,..,,,Rtz LC

14ENIORY- BANKCALENDAR

iRMF' f''. 24MR L1T LKIHT eor

vernMilliMMIMMININIONIMMOW

The 'Bond- watch fromMoonraker

Thisis the

watch offerthey said even ETI

could never do. SEIKOat a 40% discount! After all no

one discounts Rolls Royce do they?Well here it is. A SEIKO Memory Bank

Calendar watch which 'etails everywhere at £138for only £79.50 inc VAT and Registered Post charges.

The watch itself is a different league to other timepieces. It

shows day, date, month, hours, minutes and seconds continu-ously, and switches to display the full calendar, month by month, from

January 1st 1930 to December 31st 2009 at the push of a button!Twelve or twenty-four hour display can be selected and changed at will! Up toELEVEN dates in the forthcoming year can be set as "MEMO" dates in the memorybank, and upon the alloted day the watch keeps the word MEMO flashing on thedisplay to remind you of whatever it was you forgot. No more forgetting birthdays,anniversaries or evenings out!Battery life is a good two years and the watch carries the full SEIKO guarantee.(Although these watches are so reliable chances are you'll never find out how good

that is!)Operating the watch is simple and logical, and you don't need a pin to set it either!Even battery changing is facilitated by the 'hatch 'lack' construction. You'll neversee an offer like it again for a long long time, and even row we can't hold this pricefor long, so now's the time to get yourself the best there is in a watch, get a SEIKOand get it at ETI's prices!Orders can only be accepted using the coupon below, and then in order to be fair toeveryone, only one watch per coupon. Supplies at this price are limited, so forgiveus for being so formal!

0019111.1%.1919101W191910MiliTittlit %%%%% %%%%%%%%% .. ....pa- IN

0.--irwe 40 4111,

To ETI Seiko Offer145 Charing Cross RoadLondon, WC2H OEE

I enclose cheque/P.O. for £79.50 payableto ETI for ONE Seiko Memory BankCalendar Watch.

Address

MEMORIES AT MICROPRICES THE MOST VERSATILE

STAL SLAY1. 25+ 1

LCD106LIQUIDCR 6.Y2445 5.5DI 0P 00 +5.25.5" Field effect LCD dis-play featuring 31/2 digits,colon, plus/minus sign,3 decimal points and"LO BAT" indicator.Ideal for DMMs, DPMs,digital thermometers,AM/FM radio readouts.Just look at the features.Ultra low power con -

sumption, high contrastratio, wide viewingangle, rapid response,proven sealing techni-ques, superior MTBF,reflective aluminium foil.Over 300,000 alreadysold! Perfect interface forIntersil 7106.

MICROPROCESSORMADNESS

Compare our prices before you buyelsewhere

CPUs MEMORIES8080A 4.95 2102 1.006800 7.00 2114 low powerZ-80 8.50 300 NS 4.00Z -80A 10.50 5101 4.95

EPROMS UARTS1702A 4.00 AY -5-1013A2708 7.00 3.502516 24.50 AY -3-1015 4.007708 5_95

CHARACTER GENERATORRO-3-2513 5.50

do...oAll Brand

St New Prime! MakePrwe

2114-3 Low PowerHigh Speed Hitachi 4.0030ONS

2112-25 Synertek 1.952708 Eprom AMD 5.95

TRANSISTOR SALE2N3819 TEXAS 17p2N 3820 TEXAS 27p

DISPLAY LEDs ATLOWEST PRICES

DL 704/ DL 707 90pEND 500/END 510 75p

NOW THE CHIPS AREDOWN

Due to bulk purchase. we are able to offerunbeatable prices on INTERSIL chips.Compare our prices and see how muchyou save

1-24 25+ 100+ICL7106CPL 6 50 6.25 5.95ICL7107CPL 6 25 5 95 5.75ICL8038CCPD

3.00 2.75 2.15ICM7216AIJI

18.75 17 75 14.75ICM7216B1P1

16 75 14.75 12 25

LINEAR ICsLM324N Quad OP Amp 40pNE555N-8 Timer 18pLM556N-14 Dual Timer 50pLM723CN Voltage Regulator 33pLM747CN-14 Dual Op Amp 40p

VOLTAGE REGSSG780 5CP SG7812CP 55pSG7905CP SG7912CP 70p

POWER CONVERTER FC-5Now you can operate 120 Volts Americanequipment from 240 Volts,Only £9.95 complete with British typeplug

I

LED BAR GRAPH ANDANALOG METER DRIVER

New from National LM3914 Droves 10LED directly for making bar graphs, audiopower meters. analog meters, LEDOscilloscopes. etc. Units can be stackedfor more LEDs. A super versatile and trulyremarkable IC. Just out!Special price Only E7.99. ELECTRONIC YAP BOX -

DISCREET SOUNDS3

Laser Gun SirenRay GunPlus many othersUse on car PA system, bicycle horn, orprotection against would-be attackersInvent your own sound effects, makebelieve you are the police or firemen Mustfor DJs. pop groups and recordingstudios Only E9.95 inc

We apologise to our customers for thedelay in completing orders during July/August as a result of our move We arenow back to normal

Ordering infonnertion: For orders underE50 add 50p p &p Add 1 5% VAT tototal All items are subject to prior sale andtherefore subject to availability Prices aresubject to change without notice

FAIRCHILD RED LEDLAMPS

*FLV505 / Medium SHze Clear Dace REDEMITTING These are not retested off.spec units as sold by some of our corn-petitors These are factory prime, firstquality, new units

VERY LIMITEDSTOCK!!

8p EACH 100 OFF6p EACH 1,000 OFF5p EACH 2,000 OFF

Texas Instruments 1 I

Low Profile Sockets \ Lt:

Contacts Price8 PIN .07

14 PIN .0916 PIN .1018 PIN X,' .1520 PIN s;k .1822 PIN .2024 PIN . 2 228 PIN .2540 PIN 28

All orders to.

113 11113111

CinuitsINTERSIL UNIVERSAL TIMER /COUNTER EVALUATION KIT

ICM7226A EV/KIT ,,,,ra8 digits 5 Function 4 range ovto 10MHz with 0 1Hz restime interval and period to 10 secondswith 0.1 microsecond res units up to 10million and ratio A breadboarding area isprovided for user to add his own inputconditioning circuitry or prescalers anddigital outputs are available as multi-plexed as well as being displayed

Complete kit ONLY £48 + VAT

NOTE OUR NEW ADDRESS

Please note new address.4 Meeting Street

Appledore, Nr. BidefordNorth Devon E X39 1 RY

Telex 8953084

NEWS:DigEg

Casio Long Life

With the introduction of theF -8C from Casio, the age of thedisposable watch is upon us.The F -8C is fitted with a lithiumbattery, which should last forthree years. When you feel it'sabout time for a new watch,your battery will be on its lastlegs. You can strap a new F -8Con your wrist for only £12.95,complete with its three yearlithium battery. If the prices ofwatches keep coming down andbatteries become more sophis-ticated, more efficient andlong-lived and more expensive,it can't be long before you reallydo throw away your watchwhen the battery goes to the

great recharger in the sky.Meanwhile, back to the F -8C

- this new Casio ticker (with asilent tick) gives continuousLCD readout of hour, minute,second, AM (or PM), date andday of the week. It's accurate towithin 20 seconds a month andhas an automatic calendar,needing adjustment only oncein four years - on February29th. There's also a micro -light,of course. The stated batterylife takes into account fiveseconds of micro -light useevery day.

The F -8C is made by CasioElectronics Co Ltd, 28 ScruttonStreet, London EC2A 4TY. Therecommended retail price is£12.95, so you should be able toget hold of it for a little less.Moral: bargain -hunting is thebest policy.

Touch Switch

This month, in our regularmistakes mention, we featurethe Touch Switch (ETI De-cember). The componentoverlay on page 94 looks a bitodd. To put things right, turnthe foil pattern round through180°.

CCBCVLTC

IR a

LE,STROBEC

DC

AC

V SS

TOP VIEW

VDD

DC

D A

) B) C

D0E

Reaction TimerWe've a had a few inquiriesabout the display used in thisproject. The original design wasAustralian and unfortunatelythere does not appear to be aUK equivalent for the SEL 521displays used.

However, all is not lost. Manyof you have been keen to usealternative displays, but wereunable to do so, as neither thedisplay nor the driver pin func-tions were identified. With theaid of the 4511 driver pin -outshown and any suitable com-mon cathode, seven segmentdisplay, you should be able tostart timing your reactions in aflash (not literally, we hope).Common cathode, seven seg-ment displays are availablefrom most of the majormail order component sup-pliers.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 11

TTL by TEXAS 74251742597427874279742837429074293742987436574366743677436874390743o374490

74007450074017402/403740474$04

105/40674077408/409.410741174127413741474C1474167417742074217422742374257426742774287430:432743374377438744074417442A7443744474457446A1447/1744974507451745374 54/4607470747274737474/47574767480:43174827483A7484748574867489749047491/492A7493A74947495A74967497 :110074104741057410771109.'4110'4111/4116741187411974120741217412274123/4125741267412871132/413574136741371414174142741457414714148741 5074151A74153/4154741554156

741577415974160/416174162:4163741647416 5:416674167741707417274173741747417574176141777417874180/41817478274184A74185/41867418874190/4191:4192741937419474195747967419774198/4199742007.1221

Ilp1141412p14p14p90plap32p22p17p14

20p30p

110p27p27p17p40p22p34p33p40p34917p17p30p40p35p35p17p70p50p

114112p100p

93p50p80p17p17p17p17p17p

34p30p30p36p

100p50p

MO110p

104110p34p

175p30pPp48p30p54970p65p

15091300

3465pp

56p70p

200p130p210p110p

21Ip

45p55900p

7550p

75075950p50p

2130p

190p1541009

70p70p

100p90p90p70p

190p100p100p100p100p120p130p120p200p244450p120p

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160p114

100p90p

150p150p504325p

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90p90p909

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1541500

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140p250p

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INTERFACEIC.

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1110p175p3142715p2715pISOp155p224225p154380p20017200p200p ,

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2.563.75" 44p 43p2.5X5" Sip SIp3.75X3.75" 57p -3.75 X 5" 840 64P3.75817" 222p 15494.75 X 17.9" 294 -Pkt of 100 pew 50pSpot face curter 86p

n ise-Don tool 1189Vero Wimp Pen+ 2 wire spools+ combs 370pCombs 7p

LINEAR LC.AYI -0212AY1-1313AT1-1320A51-5050473.1270A55 -1224AA55-1315AY5-1317ACA3019CA3046CA3048049080ECA31386CA30896CA309040043130ECA31406043160EC431611C.A31621CA3189EDAC1408-8FX20910.7106108038LF356PL13586LM10CLIA301/1LA4311198318194319IM32419833913348IM377198380LM381ANLA4709LA1710LM725188733188741194747194748LM29171883900LM3909LM39111413914L.M4136MC13106MCI 458MC14954.MC1496MC33406MC3360PMK50398MM57160

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250p70p

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200p200p320p320p100p400p400p804876p400p

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110p27p

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40361/240364404084040940410404114069440595406734084140871/2

45p120p

70p65065p

306097p

1015p75p90pflOp

104. 400V 200025A 4130V 400p

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91115p

DIODESBY127BYX36-300044704810485049004910A95042000420215914159161144148154001/2154303/41N40051144006/7155401/31N5404/7

.1,6920

HEAT SINKSFor 10220 Voh-age Reg. andTransistors 22pFo TO5 12p

20030liplip

9P

109pP

044

SP

7p14plip9P

TRIACSPLASTIC34400V3A 500V6A 400V64BA 4001/

500t/

84 500V12A 4031/12A 5130V164 400V16A 5001./128000

60p65p70p

75p

85p95p

1041109134134

BRIDGERECTIFIERS1/1 50V 19pIA 1009 20pIA 400V 24IA 600V 30p2A 501/ 30p2A 100V 342A 400V 45p3A 2000 643A 600V 744A 1000 9594A 4001/ 100p6A 50V 80p6A 103V 100p6A 400V 120p

THYRISTORS1A 50V 40pIA 400V 643A 400V 90p8A 600V 140p12A 400V 160pI 6A 100V 1641644001/ 180p164600V 220p81106 114C1060 45pMCR101 36p253525 120p2744444 144255060 34p2N5064 40p

LOUD-SPEAKERS

21/2" 64R 70p21/2" BR Ma2" SR 110p

11/2" 85 50p

VOLTAGE REGULATORSAxed 111196c TO -220

IA5V 7805 90p

12V 7812 60p15V 7815 SOp18V 7818 80p24V 7824 1110p

100mA TO -925V 78105 34

12V 78112 30p15V 78115 30pOTHER REGULATORSLA43096 13591943111 200p144323K 550p198 723 37p

166625578HGKC78HOSKC78MGTX78605

-ve7905 70p7912 70,7915 70p7918 70p7924 70p

79105791.1279115

70p70p70p

120p725p824135p900p

OPTO-ELECTRONICS255777 45pOCP71 134 013612 90pOPT04801ATORS11674 130pMCT26 100pMCS2400 190pLEDS0 125"7X32T11209 Red 13p111211 Gr 20p711212 Ye 25p111216 Red 14DISPLAYS3015F0170401707 Red

707 GrD1.747 Red

747 Gr840357FN0500FND5073453640MA5464.0

200p144140p140p225p224120p124124174200p

ORP6008961

771178

TIL111TIL112111116

111.220 Bed111222 Or111228 RedMV5491 TS099

5585881111311D1312/3111321/2TIL3307750,60DRIVERS96389370UDN6118UDN6184

200p204320p320p

MEMORIES2102-21210762111-22112-221142114-21.4027404441165101681074620182516

ROM/PROM.7130174518874628774838774547074647174657182513793427934369344693448

CPU.160026504650268006802808134808541558060

Z130

ZBOA

EPROMS1702A251627082716

95690p/Op

90p90p SUPPORT000 DEVICES

32456532

16P 6820lip 682122P 6850

120p 82053P 8212

8216570p 8224600p 8228114 8251

140p 255200p 8257

8259280610ZBOCTCMC14411MC14412

120p500p225p300p525p*SOOp375p100p

p510p900

350p325p325p

flip350p350p

654650p650p750p400p850p650p

1000p

E12E20£10

9041254550p

1400p1100p1100p

, 1260

500pE29

800pE29

1100p400p

500p

50500p0p

320p225p225p400p525p700p

1200p5110p

1100p

78697

850p1100p1100p

DARTAY -3-1015PAY -5-1013PIM6402TMS60115C

CHARACTERGENERATORS3257/XXMCM657680-3.2513 U C863-2513 LC.5574526245

KEYBOARDENCODERAY -5-2376

SOOp400p500p400p

990pE10

600p650p

13509

£9

LOW PROFILE DIL SOCKETS BY TEXAS

8 pit 10p14 pin 11p16 pn

18 pn 22p20 pin 2422 pn 28p

24 pn 30p28 pn 38p40 pn 48p

WIRE WRAP SOCKETS BY TEXAS8 pit 33p 18 pin 70p

14 Pin 40p 20 pin 75p16 pit 55p 22 pn 80p

24 pn 90p28 pn 110p40 pn 140p

TRANSFORMERSIpso 220/240V)6.0.6 100mA Pp9.0.9 75mA 92p120-12 100mA 95p0-120 1250056 211000.25V (5VA) 250pBOB IA 2711'12V 2A 3513p'0.12-1520.24-30 IA 340p'15.0.15 1A 285p'(Please add 54 p&p chargeto all marked above our nor-mal p&p charge)

SUBMINIATURESWITCHESToggleSPST 1100

SPOT 65pDPOT 70pDPDT (centre off) 55pPush to make 15pPeakPush latchog SPCO

ElOpSLIDE MDT lapROCKER spsT 259WAFER1 11 i12W36/4W4913W26/6W

45p45p '

45p45p

ANTEX SOLDERINGIRONSC-1 5W 400pCX-17W 415pCCN-I 5W 415pX25 415pSPARE BITSC/CX/CCN 48pX25 SOp

SPARE ELEMENTSC/CX/X25 180pCC5 200pADCOLA IRONSK1000 550p

, K2000 5508

RESISTORS Hip.Stab 5% 512Carbon Fire

''1W 10R -1M 7p / 5pcsore value

1/2W1OR.10M 4/3pcsone value

Miniature PresetsHor/Ven 100R -1M 14Carbon Toot Pots5K -1M Log. UnSingle 30pSir9le weh Swish 80pDual 72p

SLIDER POTS 60rnm TrackLIN 5K 10K. 50K. 100K

60pLOG 10K

CRYSTALS100674T 300p1MH: 370p1 008MH: 370p3 2768M1-1: 350p3 579545MHz 200p4MH: 350p8 867237MH: 400p10 7M14: 350p18MH: 300p26 690M1-1: 210p27 145MH: 210p

VEROSOARDSDIP Breadboard4.1 5 x 6,1 5 270p(Suitable for 20 x 14 pin or16 x 16 pit DIL ICs) DIPBreadboard as above with tracksfor 31 way connector 340pVO Boards for 'Cs 105p(No track cuffing)

CONNECTOR PLUGS31 way Plug31 way SocketS-100 Busboard

110p114E12

EDGEBOARD CONNECTORS 0.156" PITCH2 x 10 way 115p 2,22 way 135p2 x 15 way 100p 2 x 25 way 160p2x18 way 120p

COUNTERS740.925740.9281CM72168ICM72174051040E

475p604

£20650p704

TTL & ECLMC4024MC40441 01 1 610231

325p325p70p '

350p

SPECIAL OFFERS TO 31.1.80555 £18;100 7805741 E167100 78122114L-3 £4.50 79052708 £6.75 7912

P&P +VAT Extra

£5/10£5/10£6/10£6/10

VAT RATE: Please add VAT at1 5% on total order value.Access and Barclaycard acceptedPlease send SAE for list

SREADSOARDS PROTOSOASD (R) SOLDERLESS SNEAD-EXP350 3.6" x 2.1" E3.15 BOARDS(410 3 0 14 pin ICs) Socket Strips/Bus Strips /13IndIng Posts mountedEXP650 3.6" x 2.4" E3.60 on sturdy base date(Up to 1 it 40 pin IC) PB6 6 x 14 DIL ICs E9.20C<P300 6" it ) 1" E5.75 68100 10 0 14 DIL ICs 111.80(Uto 6 x 14 pm ICs) 68102 12 x 14 DIL ICs E22.95EXP600 6" x 2.4" E6.30 P8103 24 : 14 DIL ICs E34.45(Up to 1 s 40 pin DCs) P8104 32, 14 DX ICs £46.95

(The above boa ds are suitable for all 011. IC, )IC TEST CLIPS

14 ptn E2.80 '4 r, £2.9016 pin E2.75 40 pin £2.90

16 KEY KEYPAD E4.00(Reed Switches)UHF Modulators E3.75Reed Switches (I 2VA) E0.25LOGIC PROBE E18.00MULTIMETERSSUPERTESTER 6808 E33.00MICROTEST 808 E17.00TMK500 E22.00Pocket mulbrneter £4.75

COMPUTER KITSMEMORY MAPPED VDU INTERFACE KIT

E45.00SERIAL I/P VDU INTERFACE KIT E56.00ELF II MICROCOMPUTER KIT E79.95ELF II WIRED AND TESTED E99.95GIANT MONITOR BOARD KR FOR ELF II E35.004K STATIC RAM BOARD FOR ELF II £69.44ASCII KEYBOARD KIT E50.58(Please add 75p p&p to all above Items)

We carry a large stock of 74 and 74LS TTLs, CMOS, Linears Memories, etc. and can normally offerex -stock deliveries. We welcome inquiries for volume quantities both from local and overseas buyers.

Please add 30p p&p & VAT.

Government, Colleges, etc. Orders accepted.

CALLERS WELCOMEMon Fn 9 30/5 30Saturday 10.30-4 30

TECHNOMATIC LTD.17 Burnley Road, London NW10(2 minutes Donis Hiii tube station) )ample street parking)Tel: 01.4521500 Telex: 92 800

NEWS:Digest

GRomarmcElectrarticsGRAND XMAS SALE

LOW POWER SCHOTTKYTTL ICs

EX -STOCKDevice Price Device Price Device Price Device Price74LS00 11p 74LS40 14p 74LS138 75p 74LS247 90p74LS01 12p 74LS47 50p 74LS139 80p 74LS248 90p74LS02 11p 74LS49 50p 74LS151 32p 74LS249 70p74LS03 12p 74LS73 25p 74LS153 51p 74LS251 74p74LSO4 12p 74LS74 25p 74LS155 51p 74LS273 150p74LS05 17p 74LS75 28p 74LS156 54p 74LS279 50p74LS08 30- 74LS76 30p 74LS158 52p 74LS283 92p74LS09 17p 74LS85 56p 74LS160 50p 74LS290 40p74LS10 14p 74LS86 30p 74LS162 50p 74LS298 50p74LS11 23p 74LS90 30p 74LS164 60p 74LS352 100p74LS12 15p 74LS93 42p 74LS174 65p 74LS353 100p74LS13 20p 74LS95 50p 74LS175 65p 74LS366 50p74LS14 30p 74LS107 25p 74LS190 60p 74LS367 50p74LS20 15p 74LS109 25p 74LS191 60p 74LS368 50p74LS21 16p 74LS112 25p 74LS192 60p 74LS374 150p74LS26 25p 74LS113 25p 74LS193 60p 74LS386 25p74LS27 15p 74LS114 25p 74LS196 53p 74LS670 150p74LS28 25p 74LS123 70p 74LS197 53p74LS30 14p 74LS125 30p 74LS221 65p74LS32 16p 74LS126 30p 74LS244 190p74LS37 20p 74LS132 46p 74LS245 260p74LS38 20p 74LS136 35p

LOW PROFILE DIL SOCKETS BY TEXAS

8 Pin 13p 18 Pin 25p 24 Pin 33p14 Pin 14p 20 Pin 27p 28 Pin 43p16 Pin 16p 22 Pin 28p 40 Pin 53p

REDYELLOWGREEN

LIGHT EMITTING DIODES

0.122"TIL209TIL212TIL232

Price13p22p20p

VERO PRODUCTSVeroblock Breadboards 320pVero Wiring Pen 270p2 x Spare Spools 83pSpot Face cutters 85pPin Insertion tool

for 0.052" Pins 115pfor 0.040" Pins 115p

REDYELLOWGREEN

0.2" PriceTIL220 15pTIL224-1 20pTIL243-1 20p

VEROBOARD PCBs0.1" Copper Clad2.5"x5" 57p2.5"x3.75" 48p2.5"x17" 180p3.75"55" 64p3.75"x17" 220p

Terminal pins 0.052" full pin Terminal pins 0,040" full pinper 100 39p per 100 37pper 1000 390p per 1000 360p

CALCULATORS

Texet 1 500 £3.75 Brain WaveTexet 1800 £6.40 TraderScientific 2001 £7.25 LCD 300

("Phone for details)

ELECTRONIC GAMES (No TV required)BLIP - Tennis Game

£7.70£9.00£9.40

£9.00£15.00£16.95£15.85£12.95

UFO MASTER BLASTER STATION - Guide you missile and destroy theUFO which may change course or even disappear' £17.50

COMPUTE -A -TUNECODE NAME SECTOR. - Submarine Pursuit GameINTERCEPT. - With sounds and lights of a fighter plane attackDIGITS. - Match your wits with a computer

PLEASE NOTE:All orders, large and small, will be dealt with IN STRICT ROTATION. Pleaseadd 15% VAT plus 30p P&P to all orders. (Games 30p P&P each). Exportorders no VAT but postage at cost. Prompt delivery on all orders.

ROMANE ELECTRONICS64 Newlyn Drive, Sale, Cheshire. M33 3LE

Tel. 061-962 2606

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

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Holy Messages

Before vicars all over the coun-try start sending me details offorthcoming church bazaarsand bring and buys, we havenot started a religious corner inNews Digest.

The holes are microscopicperforations in polyethylenecable insulation and themessages are telephone calls.BICC Ltd are using millions ofmicroscopic holes in cables to

the quality oftelephone calls. For their nexttrick ...

The holes in the insulation

7:.ster 1

co.. ij.4.11

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help to reduce the loss of signalstrength and also make thecables lighter and easier tohandle. They can't be any oldholes; they must be of the rightsize ,and properly distributedwithin an impermeable outerlayer. A greater concentrationof smaller holes is located nextto the wire itself.

During research and deve-lopment of the system andcommercial production techni-ques, BICC have been using astereoscan scanning electronmicroscope from CambridgeInstruments. The photographshows the cell distribution in acellular polyethylene telephoneinsulation.

Wat ProbeWhat do you give the man whohas everything? If he's an elec-tronics nut, you could solveyour present problems with thismonth's special offer fromWatford Electronics.

They are offering ETI readersthe 3300A logic probe kit at thegive away price of £14.50 +VAT - but only during themonth of December.

As you can see, the probe,with its protective cover, comescomplete with power leads, a 16pin IC test clip and a push -onspring hook. They even supplya smart pouch to tuck thetrusty tester away in.

The 3300A logic probe kit isavailable at the special offerprice, only to ETI readers andonly during December, fromWatford Electronics, 30/35Cardiff Road, Watford, Herts.Mention ETI in your order.

13

WA110110 ELECTRONSTRANSISTORS

pAC125 soAC126 20

80213EBC214

119

BER79BER80

2828110290

60110300 47

2616718 2152N2160 35033/35 CARDIFF ROAD, WATFORD, HERTS, ENIG

MAIL ORDER, CALLERS WELCOMETel. Watford (0923) 40588/9

LAND AC127 33AC128 20AC141 38AC142 24

BC214L 10BC307 13 2080309 1380327 15

BFR61 28BFR98 105BFX81 459EX84 28

11P3313 6411030065TIP318 52TIP31C 66TIP32A sa

242217 432422188 342422198 222N22208 26

23ALL DEVICES BRAND NEW, FULL SPEC. AND FULLY GUARANTEED. ORDERSDESPATCHED BY RETURN OF POST. TERMS OF BUSINESS: CASH/CHEQUE /P.O. OR BANKERS DRAFT WITH ORDER. GOVERNMENT AND EDUCATIONALINSTITUTIONS' OFFICIAL ORDERS ACCEPTED. TRADE AND EXPORT INQUIRYWELCOME. P&P ADD 30p TO ALL ORDERS UNDER E10. OVERSEAS ORDERSPOSTAGE AT COST. AIR /SURFACE. ACCESS ORDERS WELCOME.

24ACY17AC176

40ACY18 40ACY19 40ACY20 40ACY21 40ACY22 40ACY28 40

6C328 15BC338 1280441 36BC461 3690477 25BC517 3860547 12BC548 12

28BFX856288FX8

BFX87 28BFX88 28BFY50 20BFY51 20BFY52 20138753 28

IT1P32C 75TIP33C 10511P34 as11P34A 85TIP34C 11011035 18511P35C 220

2424222182222A 20242303 45242368 212423698 152N2483 ZB2142484 302N2646 48

VAT Export orders no VAT. Applicable to U X. Customers only. Unless stated otherwise, allare exclusive of VAT. Please add 15% to ell prprices.ACY44

We stock thousands moatnems. It pays to visit us. W ars situated behind Watford Foothill Ground.Newt Underground; BR Station. Watford High Street. Open Monday to Saturday. Ample Fr.* Car91.1.9 Mime thilable.

ACY39 783980741prices

39AD149 70AD161 42AD162 42AF114 50

8C549C 13BC556 1580557 15BC558 208C559 20B CY30 57BCY39 80

EIFY64 ao8FY71 zoBRY39 398SX20 18EISX26 75B SY95 A 18BU105 140

11P36A 22071P36C 255110418 63TIP418 73110428 64TIP4213 8211P147 199

242784 55242904 22242905A 22242906 22242907 22242907A 222429260 10

POLYESTER CAPACITORS: Axial lead type.400V. inf. 1n5, 2n2, 3n3, 4n7, 698, 10n, 15n Sp; 18n 10p; 12n, 33n 11p; 47n 68n 14p; 100o 17p;150n, 220n 249; 330n, 470n 41 p; 6801141p; 18F 610; 262 620.160V; 1 OnF, 12n, 39n, 1009 150n. 220n 11p; 330n. 470n les; 680n. 1,1 22p; 2 2,, F 32p; 4 1,1 36p.1000V. 10n. 15n 20p; 22n Up; 47n 26p; 100n 3116; 470n 93p; 1,F 175p

AF115 50AF116 50AF117 50AF118 55AF139 35AF178 70

BCY40 78BCY42 48BCY70 15BCY71 208CY72 20BCY78 25

BU206 190BU208 228E5567 56MD9301 158M.1491 180MJ2955 105

11P2955 651103055 6011644 4511645 451146 451190 20

243011 24243053 20243054 65243055 48243108 32243442 140

POLYESTER RADIAL LEAD CAPACITORS: 210V:10n. 15n, 22n, 27n Sp; 33n. 47n, 68n, 100n 7p; 150n 10p; 2209330n 13p, 470n 17p; 680n lip; 18 22p; 1,5 30p; 2,2 344.

ULTRASONICTRANSDUCERS

401(8, 360p pr.

AF186 50AF239 4285221 60

90124 11580131 45BD132 45

MJE340 54NUE370 58MJE371 60

11591 2421X107 1220(108 12

243663 26243702 11243703 11

ELECTIIOLYTIC CAPACITORS: Axial lead type (Values are in 8F), 5001/: 1040p; 47 Up; 21011: 10065p; 63V: 0.47, 1.0, 1.5, 2.2, 3 3, 4 7, 6.8. 8. 10, 15, 22, 114; 47, 32. I1p; 63, 100, 27p; 50V; 50. 100,220, 25p; 470. 32p 1000, 50p; 40V; 22, 33, Sp: 100. 12p; 2200. 3300, 15p; 4700, Sip; 3111/: 10. 33,7p; 330, 470, 32p; 1000, 50p; 26V: 10.22. 47. Sp; 80. 100. 160. Sp; 220, 250. 13p; 470. 640, 26p;1000, 27p; 1500. 30p; 2200, 16p; 3300. 62p; 4700 710; 151/: 10, 47. 88. 7p; 100, 125,11p; 220, 330.14p; 470, 111p; 1000. 1500. 20p; 2200, 349; 10V: 100. Sp; 640, 12p; 1000, 14p.TAG -END TYPE: 450V: 100,F 180p; 70V: 4700. I 65p; 64V: 3300 130p;2500 114p; SOV: 4700 160p;3300 106p; 2200 99p; 40V. 15.000 399p; 4700 120p; 4000 92p; 3300 113p; 500 85p; 30V: 4700110p; 251/: 6400105p; 47005{p; 3300809; 220060p. .

50107 10801078

10BC101310

1301088 1012p716-i- 10

501098 1212

50114 2080115 20

90133 4350136 38

4080137 4050138 50EID139 4080140 3680144 198130145 198BD205 110

51.1E520 65MJE521 74MJE2955 99MJE3055 70MPF102 66MPF103 36MPf104 36'MPF105 36MPF106 40MPSA05 25

11X109 1427X300 132TX301 16211(302 20ITX303 25Z13:304 24211(314 2411(-926 40ZTX341 20211(500 15

243704 11243705 11136

243706 11243707 116,,,..6,.

243708 11243709 11243710 165010,

243711 12243771 275243772 195

M MEAD CAPACITORS35V: 0.18F, 0-22, 0-33, 0-47, 0.68,1-0, 2.28F, 3-3, 4-7. 6-8. 26V: 1-5. 10.20V: 1;5 18V: 10,F I3p each.11111: 15. 22 25p. 47. 100, 22040p-101/: 15, 22, 33, 209; 100 35p.IIV: 47, 68. 10030p; 31/: 100 20p.

'

POTENTIOMETERS: Rotary, Carbon.Track. 0.25W Log & 0.5W Lin. 4700,6800. 11(0 & 2K0 (Linear only) SingleGang 27p 51(0-2M0 Simple Gang Log & Un. 27p51(0-2M0 Single Gang D/P Switch 65p5K0-2.0 Double Gang Log & Lin 7Se

COMPUTER IC.2102-2 2252111 1952112-2 2502114 4492708 87627L08 9952716 E24

BC117 . 20SC119 28BC140 3580142 30BC143 30SC147 88014711 1050148 8

BD378 6580434 42BD517 65606958 655D696A 65BF115 34BF154 2558158 29

MPSA06 25MPSA12 42MPSA55 25MPSA56 25MPSUO2 58MPSUO5 50MPSUO6 56MPSU52 65

211(501 1587X502 1911X603 1521X504 25211(531 25I7X550 2540311 6040313 125

243773 731.11

243819 22243820 45243823 962N3866 90243903 20243904 18243905 13

MYLAR FILM CAPACITORS10011: 0001. 0032, 0-005. 0018E Sp0-015. 0.02, 0.04, 0.05, 0-0568F 7P0,18F, IN. 0.2 11p. 501/: 0.47,F 12p

SLIDER POTENTIOMETERS0-25W log and linear values 60rnin51(0-500K0 single gang SOp1060.5001(0 dual gang sop

4116-16 10254047 7506502 99581LS95 125

801488 10801480 1080149 8BC149C 10

88167 308E173 25BF177 248F178 25

MPSU55 55MPSU56 600026 1700028 150

40315 5540316 8540326 5240327 6240347 80

2N3906 172N4037 52244058 172144061 17244062 17tERPJAIC CAPACITORS sell

Sell Stick Graduated Betels 215, 81LS96 126BILS97 135

BC153 27BC154 27

8F179 3088180 35

0035 1300036 130 40348 105 245172 asRings: 0-5pF to 10.0009F 49

0-0156F. 0-0228F, 0-033,F 5p0.0478F tip; 0.18F. 0.2,F 7p

PRESET POTENTIOMETERS0.1W 500-5.0 Miniature Vertical& Horizontal 7p

47-3-1015 SSOA7-5-1013 39947-5-2376 920

BC157 10BC158 11BC159 11

E1F194 1213F195 128F196 12

0041 480042 480043 55

40360 4340361 as40362 as

245179 80245191 70245305 404

SILUR MICA (Values in pF) 3-3. 4-7,10. 12. 18, 22, 33.47, 50, 68, 75,

82. 85, 100, 120, 150. 220 6p each

0-25W 1000 -3-3M0 hoar larger 1090-25W 2000 -4-7MO Van. ,t6

...

MC1488 85MC1488 90MC14411 695

BC160 42BC167A 11801680 12

8F197 14BF198 13BF199 18

0C44 310C45 28OC70 28

40408 7040594 9040595 98

245457 32245458 32265459 32

250, 270. 300, 330. 360, 390,470, 600, 800, 820 16p each1000, 1200. 1800, 2000 204 each

7.- -

RESISTORS - Erie make 5% CarbonMiniature High Stability, Low noise

MC14412 1080MK4027-2 470MK4027-4 350MK4116-4 1025

BC169C 14BC170 18BC172 11BC177 1

BF2008F2248

3218

BF24415 30BF256 eo

0071 280072 450074 550075 46

40603 6540673 6824697 2524698 44

245485 35245777 48246027 40246109 50

POLYSTYRENE CAPACITORS:10pF to InF Op; 1 5nF to 47nF 109

RANGE VAL 1-99 100+14W 2.204.7M 624 2p I.,VtMi 2.20-4 7M E12 2P IP

MK41184 2099R0-3-2513 650SFF96364E 1050

BC178 1

ElC179 1

BC182

BF256A 5013F25613 50BF257 30

0076 as0077 7600810 50

2N699 54257064 1924708 19

250234 603N128 11234140 112MINIATURE TYPE TRIMMERS

2.5-6pF, 3-10pF, 10-40pF 22p5-25pF. 5-45pF; 60pF, 88pF 706

r

1W 220.10M E12 1111 4p '2%Metal Film 1(X)-1Mtl sp 4p1%0.5W 510-1M E24 6p {p100+

SFC71301 820TMS4035 250TMS4039 250

BC18380184BC182L 1

BF258 30BF259 30BF451 20

0082D 500083 450084 44

24918 4024930 18 -2N1131 22

Matched Pair25p sm.-

COMPRESSION TRIMMERS p444 applies to Resistors of etibh TMS4045 1083 BC183L BF3361 36 00140 110 241132 22 .34098; 10.8098:F, 25-19098 309

type not mixed values. TMS6011 355 8C184L 1 8F594 40 OC 70 es 241303 50100-500pF 46p 400.115098 539 TN RMISTORS: VA1034. 1039.

2130 CPU 2.5M 990Z80 CPU 4M 1099

80187 2880212 9

9F595 38BFR39 25

DC 71 7500203 as

251304 50241305 28

OAS & SMOKE DETECTORSTGS 812 6 8134159; Socket 259

1040, 1055, 1056. 1058. 1066, 1067.1098, 1100 219...h-

280 P10 660- zeocrc 696

BC2121. 1080213 9

BFR40 25BFR41 28

TIP 9 43T102913 56

2N1613 23241670 150 .WELCOME

JACKSONS VARIABLE CAPACITORSD,eltx,r,c 0 2 365pF with slow100 /300pF 16051 mob. Drive 345P50098 1650 00208/176 285p61 Ball Dove - -1.491514w4511/ DAF 1169 motion drive 345pDial Nye 4103 C804-5pF 10 156.1/36 1 650p 26 50pF 1759Drum 54min 309 103. 150pF 2359

DIODES6,61P6Am19

1805

92100 2487126 1285127 12CR033 157089 75

BRIDGERECTIFIERSiplasaa caaa) pIA / 505 to1A/100V 221 A 200V 251 /1// 4008 2 91 A 600 34

LINEAR ICs702 75709 14 pin 3870908 6, 75710 .

67

723 14 pin 38733 99

741 8 pin 17741805 35

ICM7555 SiLD 30 /112LF356 esLMIO 325LM301AP 30LM308T 110LM311 90LM3186 196LM324A SR

NE567V 170NE570 37566571 420R041360 120SAG102401 1360S03402 2966476003N 1705476013 170547601340 130

-rn. 74(TEXAS)7400 117401 117402 117403 127404 127405 13

7491 507492 307493 267494 487495 487496 457497 1574100 8674104 62

74185 8074188 27574190 4574191 4574192 4574193 4574194 4074195 4074196 45

6194 965195 7996241 1955262 MI55287 3256288 210S47(3 3265472 11505475 1128

113 50114 50122 70123 70124 180125 60126 60

-132 95136 55138 850.1 365pF 2459 'L 3,310pF 5959

00 2 365pF 275p 00.3x2598 4309047 120870 12

24/i 50VV 352A / 1005 44

747C 14 pin 707480 9199 35

LM339 7090

5476018 1185476023 170

7406 237407 30

74105 8274107 20

74197 4574198 8074199 74LS 139 as

145 108RF CHOKES1,H 4.7. 10 22. 33. 47. 100. 200 470750, IthH. 2.5. 6 10 31p each43rnH. 100 00P each

0879 150897 150485 140490 70491

2A / 2005 452A/40011 132A / 6 005 654A / 1005 72

753a Pin 1-,,810 159AY -1-0212 580

. AY -1-1313A 680A1-1-1320 315

LM349 125LM379 375LM 380 80LrnI113814 143

- LM382 125'

5476023ND 130S4760334 176S4761154 215SN76131 110S4762274 115

7408 137409 147410 147411 147412 17

74109 3074110 54 .74111 6074116 15074118 70

00074220 12074221 13274246 20474247 204

00 1101 1102 1303 13

147 170148 173151 96153 76

VEROBOARD 0 1 0 15 0 15(topper clad) (plain)

2% 3'4" 466 396 2462V z 0 5" 55p SOp 31p3% 354" 55p 5 -3% x 5" 629

67p79

43p215 17" 1699 1356 92p3% 17" 218p 180p 120p414 x 17" 2809 - 183p

70895 508200 908202 SN914 44916 544001/2 5N4003 5N4004/5 5N4006/7 7

4A/200V 76 48/4005 754A / 6005 1054A/80051206A/ 100V 736A / 2005 756A /4005 8581164 95VM 18 OIL 40

851-6050 190AY -1-5051 145AY -1-6721/6 195A1-31270 34042'18588 398AY -5-1224A 260AY -5-1230 45CIAV -51315 560AY -5-13174 630

LM386 99LM387 150

L389LLA14589350

LM3900 50LM39094 70LM3911 125LM3914 220LM13600 126M25248 750

6476477 2285476660 90508629 295TAA550 60T48960 320TAA621AX1 22.11

TAA661A 155TAA700 363780100 159

7413 217414 307416 267417 2111

7420 147421 297422 197423 177425 16

74119 1074120 7974121 2574122 3174123 3574125 3374126 3174128 6074132 42

74248 24074249 20474251 12674265 6374273 32074278 22074279_ 1197.4°2 17374284 38574285 395

04 1405 2306 2209 2210 2011

1.-2

2223

' 4 3814 7515 30

155 96156 96157 76158 95160 128161 98162 138163 102164 114165 75Pkt of 36pirs 20p DIP Board 268p

Spot taw cutter 56pVO Board 90p

Pin Insenan tool 120pS Board 1270p

EURO BREADBOARD 530PVERO BREADBOARD 3409

l+-

54148 445404 17S44 2034/1005 1634/40:6/ 203A/1035 273A/1000V

ZENERSRange 257 to395 40OrnW

lip ashRange 353 to33V 1.3W

AY -5-2376 980AY -5-3500 510AY -5-3507 415A1-5-3600 1090

, A55-40070 650' A55-8100 736

CA3311 100

M253AA 795MC663 275MC1204 000_MC1301 79MC1303 88MC1304P 260MC1310P 173

TBA1205 707885400 2207885500 330T81641+512BX.13X11 2501138651 150TEIA900 SO

7426 257427 187428 357430 157432 157433 407437 17

74136 BO74141 4274142 16974143 25074144 25074145 5274147 110

74290 12574293 15074298 18574365 12874366 11874367 11574368 124

20 2021 2226 1827 2828 4430 2232 27

166 226170 280173 105174 106175 110181 398183 298

VERO WIRING PEN 311 169 ..eh CA3012 150CA3014 137 MC1312P0 196

TBA810 95788820 70

7438 177440 13

74148 BO74150 50 74390 184 33 39 190 140

Plus Spool 325pSpare spool (wire) 000 Combs 7p each NOISE

SCRs083018 eraCA3020 170

MC1495 350MC1496L 92

1889200 260ThA9903 270

7441 667442 31

74151 3974153 50 7449074383

It19.

37 39'38 3640 28

191 140193 130

FERRIC CHLORIDE-Z 5 J 180

083023 170 MC1596 000 1082700 220 7443 10 74154 60 75150 120 194 166

183 bag Anhydrous 969 + 359 P&P VARICAPS Thyristors CA3028A 80C43°3° 24°

MC3302 000MC334°P 120

108965 1207081004 290

7444 807445 50

74155 4574156 45

75450S478451

42 1111

47 43195 136196 100

GAL° ETCH RESIST PEN -4- spare tip 75p- MVAM115.., 0 6A2005 300 BA 1005 30 CA3036 110 MC3360P 120 TDA1008 310 7446 86 74157 36 75452 70

75454 22548 12049 120

197 140221 96COPPER CLAD BOARDS

Fibre Single. Double SRBP. 88102 175...,' . . . '40 -

0 8/1200V 355A 1005 3258400

inCA3°4,,3,.. 191'24,....C.A..,.....! 3881. -...-.-".. 71

MC3401 52'..912,349,2 135"4191'9. 2°5

TDA1022 576TDA1024 105TDA2020 320

7447 437448 457450 16

74159 16074160 5574161 55

75491, 8575492 94 54E.1 29

240 236241 232

Glass sided sided 9 5" 0 8.5"6" 6" 75p 90p 110p6" x 12" 130p 1750

8888110°458

1313106 40.._ .

5 39586005 43.'883005 45

CA3048 210083375 175

m,C6040 97....'hh..,,,,..,,,.., ,...,888

.".".1-.., .111.

now" 767L062CP 125in

7451 167453 111

7454 16

74162 5574163 5574164 60

-6..1.4.L74100 65

55 3063 15073 45

242 232243 232244 155

SOLDERCON PINS HEADER PLUGS100 50p, '. 'r, 200p 14pin 31p; 16pin 39p

I

TRIACS3870011 45

845005 58886005 56 128100542612A300 59

C43°80E 70C43081 190083085 95C43°898 210

MK50398 635..M.,91.51.9.3 LW

'.."',99...,..,' 1.2.,...79

Tilinch071 76TL072CP 12511.07404 199

7460 167470 237472 23

74165 6074166 7574167 150

L30 70147 599L75 298

74 4175 4576 40

245 270247 190248 190

OIL SOCKETS(TEXAS) Low Writ

pot Wr.pEDGECA3090110CONNECTORS:(Double type

3A400V so881005 54884005 64888005 108

51285005 921248005 120BT 106 1 50

393CA3123E 200,,.0 43. 13, 2 90

'''''''°' ... 8.15E515

asNE518 210NE5438 210

TL081CP 52TLO82CP 95TL083CP 105TL084CN 130

7473 197474 207475 257476 22

74170 9574172 35074173 6574174 50

L85 525L121 1501123 495

78 4083 11585 11886 43

249 190251 134253 142257 1108p,n 10p 25p

14pin 12p 35p16Fin 139 46p18pin 169 52p20pin 22p 65p22pin 269 70924pin 36p 78p

.1 .1562,10 nay - 35P205 way - 9992,18 way 1156 120p2,22 way 130p 13592,25 way 1499 160p2,30 way 1706 --

12/11005 50, 76,400g 7012A13005 1151641005 24011684005 1061685005 1202585005 235

BT 116 1 50C106D 38T IC44 22T IC45 252 4 4444 110245064 35

1-.9.45 7090L7106 795L7107 9751803800 333M7205 1150M7215 1060III

CM7216A.1 1950

NE544 166NE555

..88.

......=NE560 4.95E561 395

. NE562B 410NE564 425

uAA170 198UAA180 19881.4414 90244246 1307214256 4152410346 200

605

.

7480 407481 707482 487483 497484 807485 707486 18

74175 5574176 5074177 4574178 4074179 00074180 5074181 110

74S'74500SO4 73S132 3505138 2505158 524

3891 104

511

93 8095 11696107 44

258 110259 160261 450266 52273 244275 250279 6628pin 399 859

36pin - 1059VOpin 509 1099

2,36 way 1949 -

2,40 way 210 -2,43 way 232p -

25A8005 295728000 120

. -DIAL;ST 2 20

CM7216B 1950CM7216C 1950CM7217A 790

NE565A 120NE566 160

181040E

AlINIONIM,

7489 1307490 30

74182 3574184 135

5188 2100189 168_

109 56112 55

283 1921290 128

1,1 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

wATFORD ELECTRONICS

THE DIGITAL FREQUENCY METER with a Differencep11.01166601""666ITIOST,Ir ' 0-150MHz in 5 ranges

' Large 8 -digit display for high accuracyPeriod and time interval facility.Unit counter up to 99.999.99910MHz crystal timebase

' Hold and reset buttons plus built-in PSU.All these features and more for less than half the price of an ordinary frequency meter. TheDFM2000 has all its components including the displays, switches and transformer mountedon one double sided PC board. Assembly is simplicity itself especially since interwiring hasbeen eliminated. This is a high quality design and will make a truly professional digitalfrequency meter that any constructor will be proud to own.

Price: Only £64.60 Kit (P&P 65p)Ready -built and tested £74.50Probes: Optional extra E8.715

OHIO SUPERBOARD IIOnly £188.00

Yes. we are now selling this popular single boardmicrocomputer at the giveaway price of E188.00 Dueto the recent devaluation of US Dollar against (Sterlingwe have been able to purchase Superboirds at lowerprice. Naturally, we wish to pass this price advantage onto our customers Superboard II is supplied fullyassembled and tested to British TV specification Alsoincluded at no extra cost 4 manuals and a Cassette withprogrammes. Requires +5V at 3A and a Video Monitoror TV with RF Convertor to be up and running (Datasheet supplied. We can also supply the RF Convertorand Power Supply in Kit form or ready -built)8K Microsoft BASIC in ROM 4K Static RAM - onBOARD expandable to 8K Full 53 Key Keyboard withUpper/Lower Case & User programmability and a lotmore. Seen for yourself. Continuous demonstration onat our retail shop.Specially designed attractive fibreglass case (VDU Unitcan be mounted on al E26.00Power Supply Kit with RF Modulator E21.76Extra 4K of RAM E35.00

*WITCHESTOGGLE 2A 250VSPST 28pDPST 34pDPDT 36p4 pole on / off 54p

SUS.MIN TOGGLESP changeover 59pSPST on/off 544:SPST based 85pOPDT 6 tags 709°PDT centre off 79pDPDT Biased 115p

SUDS 26011:IA DPDT 14pIA DPDT cioxer 15p1/24 DPDT 13p4 pole 2 -way 24p

PUSHBUTTONSadedSPST on: off 60pSPOT c/over 85pDPDT 6 Tag 85p

MINIATURENew lookingPuah to Make 15pPush Break 25p

ROTARY: Make your own multiway SwitchAckustable Stop Shafting Assembly. Accornmodete up to 6 Wafers 75pMeals Switch DPST to fa 34pBreak Before Make Wafers 1 pole/ 12 way2p/6 way 3p/4 way 4p/3 way. 6p/2 wax

47pSpacer and Screen 5pROTARY: (Adjustable Stop)

1 pole/2 to 12 way. 2p/2 to 6 way 3

pole /2 to 4 way. 4 pole/2 to 3 way 41pROTARY Mains 250V AC 4 Amp 45p

CRYSTALS100KH: 323455KHz 383

MHz 323008M 39528MH: 3926MH: 3238MH: 3238432MH: 362

2 4576MHz 3623.2768M 3233.57954M 1954 000MHz 2904 032Mhz 3234 433619M 1355 OMHz 3555.185M 3236 5536M 2007 680M 3238 86723M 3239 375M 32310 OMIlz 32310 7MH: 32312MHz 39214 3181MHz 30018MM: 32318 432M 32320 OMH: 32327 648M 32348 OMHz 323100 00MH: 323

TRANSFORMERS (Mains Prim 220 240V)6-66V, 9-0-9V. 12-0-12V 100mA 95p3VA: 0-6V 0-6V (PCB mounting) 150pSV& 6V- 5A 6V- 54: 9V- 4A 9V- 4A: 12./..3412V- 3A, 15V- 25A 15V- 25A 195p12V: 4 5V -1.3A 4.5V-1 3A, 6V -1.2A 6V -1.2A.12V. 54 12V -.5A. 15V -4A 15V - 44, 20V -3A20V. 3A 220p 120p p&p)24VA: 6V 1 5A 6V-1 5A. 9V-1 3A 9V -I 3A.12V-14 12V14, 15V. 8A 15V-.84, 20V 6A20V. 6A 290p (45p p&plBOVA: 6V -4A 6V-44. 9V-2 54 9V.2,54. 12V-2,412V24 15V1 54 15V-1 54: 20V-1,24 20V-1 2A. 25V14 25V -1A. 30V- 84 30V. BA

3150p (50p p&pl100VA: 12V-44 12V-44. 15V -3A 15V -3A20V-2.54 20V -2.5A. 30V -1.5A 30V- 5A.40V -1.25A 40V1,254, 50V.1A 50V -1A 650p(60p p&p) (N. B p&p charge to be added aboveour normal postal charge

ETI Proiects.Parts availablefor: ClickEliminatorDFM 2000FrequencyMeter,DM 900,AudiophileAmp, 60WAmplifierSystem. SendSAE plus 5pfor 5st.

VOLTAGE REGULATORS14 103 - n -xe5V 7805 145p 7905 220p

12V 7812 145p 7912 220p15V 7815 145p18V 7818 14Sp14 10220 Plastic Casing5V 7805 65p 7905 75p

12V 7812 Up 7912 7Sp15V 7815 65p 7915 75p18V 7818 Up 7918 75p24V 7824 66p

100mA T092 Plastic Casing5V 78105 30p 79L056V 78162 30p8V 78182 30p

12V 78112 30p 79112 65p' 15V 78115 30p 79115 6Sp

6Sp

144300H 170p LM327 270pLM305H 140p 1M723 38pLM309K 135p. TAA550 60pLM317K 350p TBA62 B 95pLM323K 5150p TDA14 2 150pLM325N 240p 78H05 +5'54595pL.M326N 240p 78HG 5 to +24

650p

ALUM.BOXESWITH LID

P35251" 5421/4551/4511/2"

7244:11/2" 72452'451'/" 704:5ff51l4" 884:Thx2" 725:42" II6:4:2" 108755021/2" 14513:6:3" 16510:70" 2101054'4x3" 17512:50" 215125853" 265

OPTOELECTRONICSLEDs with ClipsTIL209 Red 13TIL211 Grn 17711212 Tel 15T11220 2" Red 142" Green, Yellow

or Amber 18Square LEDs. Red, 7 Seprrient DiepleyGrit , Tel 36 TIL307 67511132 Infra Red 68 TIL312 3" CA

TIL313 .3" CCL5400 255 TI1321 5" CAOCP71 120 111322 5" CCORP12 63 D1704.3" CCORP6I 85 DL707 3" CA2N5777 45 DL747 6" CA

END357 Red3" Green CA6" Green CA

PANELMETERSFS060:46.35mm0-50,40-100KA0-500,4

Inak0.5rnA0-10m40-50mA0.100mA0-500m40-1A0-240-25V0-50V AC0-300V AC

VU475p each

41/4x3,41,11/2"0-50,40-100,A05000A65Sp each

ISOLATORS1174 48TILIII 2 55

4 95111117 110

LCD 3Y: DigitLCD 4 Digit

105105115115

9999

180120180225

875975

293 125295 165298 168324 240325 290326 294327 246347 148348 186352 228353 228365 65366 IS367 65368 so373 190374 180375 160377 212378 164379 215384 66390 230393 230395 216396 215398 276399 230445 150447 144490 180668 182669 182670 248

CMOS*4000 124001 134002 15

4006 68 4045 1454007 15 4046 664008 56 4047 874009 30 4048 584010 27 4049 284011 18 4050 334012 14 4051 454013 35 4052 454014 55 4053 454015 63 4054 1104016 25 4055 994017 60 4056 1104018 SO 4057 16504019 32 4059 4804020 70 4060 904021 52 4061 12004022 50 4062 9954023 14 4063 1104024 45 4066 304025 IS 4067 2804026 100 4068 IS4027 35 4069 154028 50 4070 154029 54 4071 154030 50 4072 154031 150 4073 154032 80 4075 154033 95 4076 574034 199 4077 164035 80 4078 164036 325 4081 164037 100 4082 154038 108 4085 624039 320 4086 524040 58 4089 1104041 60 4093 394042 50 4094 964043 46 4095 484044 52 4096 106

409740984099416041614162416341744175419444084409441044114412F4412V4415F4415V441944224433443544404450445144524490F4490V45014502450345064507450845104511451245134514

37299

14578767575d29090

670670670695

12501050

520350280426750540

1275260220

310240

1657424635

19555BO70

206150

4515 195 4549 3764516 52 4553 3984517 382 4554 1504518 63 4555 464519 56 4556 444520 63 4557 3654521 228 4558 1064522 145 4559 3764526 65 4560 2104527 53 4561 654528 52 4562 3754529 145 4566 1564530 65 4569 1804531 135 4572 264532 67 4580 511154534 575 0581 2974536 365 4582 1304538 142 4583 754539 106 4584 634541 135 4585 1054543 155

ILP MODULES

Full range of these fully guaranteedmodules available from stock at BeILP's advertised prices.

RE MODULATOR 250pWidened modulator for computers

470p

NEWS: Digest

PocketCompanionNot just an electronic dictio-nary or a translator or anappointments diary or an ency-clopedia, but something of allthese rolled into one, the'Brainbank' is hailed as theworld's first pocket informationcentre and languagelaboratory.

Brainbank is programmed viaa series of interchangeable,plug-in memory cells, so youhave virtually unlimited infor-mation storage possibilities(armed with a bucket full ofmemory cells).

Each language cell, whichcontains 32K of ROM holdsabout 1200 of the most common

The ThinkingMan's PlugGalatrek's 13 Amp SocketTester, introduced in 1978, hasbeen such a success that theyhave just introduced two newmodels. The first is a six func-tion socket tester for any typeof socket. Fit your own plugand see from a neon displayimmediately if the socket isalright or has a live fault, neu-tral fault, no earth, live earth

words, stored individually andin groups of up to fifty in cate-gories such as travelling andfood. The program also includesshort phrases, automaticallycorrects spelling errors and ex-plains words with doublemeanings (with its double en-tendre chip?).

The information centre'sheart is a Mostek 3870 micro-processor. Memory cells arecurrently available on diet andnutrition, first aid, taxation anda thesaurus. New cells will be-come available every month. Acustom cell service is alsoavailable.

Brainbank will cost around£150 plus £20 or less for eachadditional cell. We will tell youmore about this little marvel,when we can get hold of one toplay with.

reversed or reverse polarity.The second newcomer is a threephase tester which instantlyindicates if phases are functio-nal and if there is an earth.

Both testers are availablefrom the manufacturer. The sixfunction 13 ampSocketTester is£4.50 and the three phase modelis £8.95. Both prices includeVAT and UK mainland postage.

For further details contactGalatrek Engineering, ScotlandStreet, Llanrwst, GwyneddLUG OAL, North Wales.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 15

L9.1

TEA.NAM OPRODUCTSMPll

T E

TRITONSINGLE BOARDPERSONALCOMPUTER

THE CHOICE IS YOURS! ONE OF THE MOSTVERSATILE COMPUTERS AROUND TODAYUsing the Titon main PCBas a starting block, thesingle board holds CPU,VDU, 8K memory tape I/O,power supply and comescomplete with case, fullkeyboard, 64 graphics.The Triton system builds in many ways to suit yourbudget and requirements. All parts are availableseparately. The system is easy to expand and is wellsupported with comprehensive documentation.

NEW FIRMWARE OPTIONS14.1

L5.1

16.1 New

The Level 4.1 Triton consists of Triton main PCBwith 3K resident firmware. IK Monitor and 2K TinyBasic. Complete kit.

Triton kit with 4K Firmware in Eprom 1.5K Monitorand 2.5K extended tiny Basic.

Triton with 7K Scientific Basic, Complete withMotherboard and 8K Eprom Card and 2K Monitor.

Triton with 8K TCL extended Basic in Eprom. Fullstring handling and all the standard features of fullBasics.

18.1 NewTriton with Resident Pascal in Eprom new TCLPascal Compiler in 20k on board. Includes 4KMonitor/Editor. A total of 24K of Firmware.

New CP/M compatible disk interface for Triton.WAN drive up to 4 x 51/4 or 8" Shuggart drives.Single or double density or sided. Requires min. of16K Ram. The ultimate in flexibility and plenty ofCP/M based software available. Prices on request.

£286.

£294

£399

£409

£611

NOW ON TRITON!

* TCL* EXTENDED BK BASIC TCL* PASCAL COMPILER* CP/M* DISK INTERFACETCL Pascal also available to run under CP / M E92 - on 8" disk.CP/ M is the trademark of Digital Research.TCL is the Trademark of TCL Software Products

COMPONENTS 74LSXXS174130111 .18 9174105411 21 S0741.01380 75 51741.5199A .85 507410E91 2.56

11174191111 .18 511741.1591 .21 9045131111 75 01741.31991 120 0/1744532511 2.55

81414130211 .20 31743631 130 107411471 1.20 9174519711 121 97415327M 295NUNN .18 91741.179 35 5874.01191 1.75 0/041s120 125 917410352N 1.35

511741834e

3174-5 1743081

.2920

$174574151745759917442791

4046

0041.115111

5W744315311

51174015411

15so1.60

917E020191744024111

011741324211

2.201.99790

9174/L353N9174101691

917471365M

7500565

5174331:191

.2o

.22 3174.07811

.35

.35 5174131559 125 91741524311 795 9174111601 .65

51742109 .18 0074608341 1.15 9743159 1.25 007440244M 210 91741335E01 .65

0579311N .Z6 $1743851 710 011741315711 .to 5674152451 1.60 007413173N 1.75

511741.8120 .25 9745861 AO 9041315111 AS 1/1741.124711 1.25 917470374k 1.70

917178131 .55 9174.0901 65 00711.519311 1.15 51741.02919 1.99 067453791 .72

9174131411 89 91744091M 90 0104818111 1.15 91741524911 1.30 917410377M 1.75

0104101511 25 0117409211 90 517431621 1E5 3174132514 745 59743379 1.32

91141.5201 20 511741.393911 .to 9174101631 .to 00747125311 1.25 011741.03791 1.40

se 41.0210 26 51174659W1 1.20 917470164N 150 91741.125711 1.40 0/1741326111 3.65

511743220 26 91741036N 1.75 587451668 1.70 917402591 .95 5474171841 .57

011741.1260 .29 91741.01070 .33 05741118901 1.75 017(0259X 1.45 S074753300 1909174712711 35 9174131001 39 9174131681 195 WAVES 29 S117E53938 1.50

111741.12111 .35 01741.0112M 30 91/4/01691 1.95 007410261N 3.50 0104133991 1.90

11174751011

NUM2527

1074/S113a917415114N

4444

51743170101174101731

2-502.20

1074702691011741.02731

.331.65

91741339E01

51074.139101

1.702.75

WIN= 39 01041312211 79 011741.417411 1.15 91741.027011 .71 91741039911 1.60

8174133111 .29 904E01231 90 311741.3115/4 1.05 317410280/1 1.75 9174714248 4.50.29 011701291 190 0174.8111111 275 9041.120311 1.80 011744044.91 125ANON

NCO 25 S174411291 .65 007010 1.75 9174152989 100 917E1449 1258174134211 .79 91741125N .ss 91741319111 1.75 50747129111 5117411459 1.95

MUNN 95 S11741313211 75 917451991 1.45 5x7470295411 7_29 90471660 eS

MANI .95 917401531 .39 5974151931 1.75 0/1741.029131 2211 517411E6E 80

_MUM 1.09 9745135 44 91741.S194.10 199 01174113241 1.80 0E41167011 2.70

TRITON DOCUMENTATIONAvailable separately as follows. Prices include P&P.

Triton manual - detailed circuit description +constructionaldetails + user documentation on level 4-1 monitor. Basic £5.70

L4.1 Listing + listing of lk monitor + 2k tiny basic E4.20L5.1 user documentation on level 5-1 firmware ...... £1.2015.1 Listing + listing of 1.5k monitor and 2.5k basic £5.2018.1 User documentation on 7k basic interpreter E1.80Motherboard, 8k Ram and Bk Eprom constructional details . £5.00User Group Newsletter subscription, E4 per annum.Triton software. Send SAE for list of programs available from Triton.

TEA.NAM

EXPANSION MOTHERBOARDu8 S4-way

con.,iirt

LOTd

TRITON. Expand your Triton simply and easilywith our new 8 -slot motherboard complete with 84-sesits own PSU; takes 8 plug-in Euro cards. Plug-in8k RAM card and Eprom cards now available.Kit complete with PSU + 1 set connectors. From

Now ! - CP / M Disc Interface. £50+ VAT

8K RAMCARD

Triton 8k staticRam card kit uses21141 low power 4kstatic rams on boardregulation. Memorylump select.PCB only £15. Rams £5.50., Kit less Rams £35

,(includes all skts and components).

£97VAT

8K EPROMCARDTriton 8k Eprom cardkit, designed to take up to8 X2708 Eproms (1k X 8).PCB only £15Kit less Eproms E31Eproms (blank) E9Plus VATFOR TRAPOR 6.1 BASIC

S100 boards8k Static RAM board (46004) E123.758k Static RAM board (25Ons) E146.25280 cpu board (7Mlir) E131.25280 cpu board (4M Hz) E1 53.752708/27 16 EPROM board E83.75Prototype board (bare board) AvailableVideo display board (6406. 128U /7 Asc») £108.75Disk controller board E131.25K2 disk operating system E56.25Assemble /Z Macro Assrn E37.50

SHUGART DISK DRIVES INSTOCK

ITHACA DPS1Pascal /ZBold your ownPascal MicroDevelopmentsystem. IEEE -5100 bus systemusing DP51 main-frame. Supports K2.assemble/ Z andPascal/2 on 8" disk.We stock the full range of ITHACA products.

YOURLONDONDEALER1

PCB CONNECTORSgold contact. double-sded PCB connectors1" Price .156" Price

22/44 £3.21 6/12 E1.2525/50 E3.110 10/20 £1.6028/56 E3.90 12/24 E2.0030/00 E4.15 15/30 E2.211

35/70 E4.611 18/36 E2.3036/72 E4.75 22/44 E2.6540/68 £5.06 21/56 E3.3043/84 E5.50 31/77 E3.90MIN E5.90 43/82 E4.60

+VAT

Triton resident assemblyTRAP! language package.Links via the 76.1 monitor and new scientific basic to make Triton astand alone development system. Trap is an 8k package in EPROMand resides on our EPROM card. Set of 8x2708 only E.80 including.document EDITOR BREAKPOINT ASSEMBLER SINGLE STEP DISASSEMBLER TRACE SYMBOL TABLE PROGRAMME LOAD CREATE MONITOR

Development System

MEMORY AND SUPPORT CHIPS (PRICES EXCLUDE VAT)SUPPORT8212 2206216 2208224 2108226 2.2002Z8 4.208238 4208245 11.008246 11.008251 5.938240 11.008256 5.008257 11.008259 12588292 18.016820P 4.5093212 4.5068513' 4.60511527 sso4162376 11.901E14411 12.001457109 12.43057146 eto067151 10.00

900E011 5.0D817095 120111.396 IAD6I1397 1.801113% 1.80

RAMS2101

2102L-4

2111

2112

0310

8134

2114

21021.3

748920

740921

74C:929

4027

4044

404.5

4060

4050

2107

4116

4118

280010

280 Zit3801 P 10

2811046

2.321.292.322_46

4.068.185501.60

11.0011.00

11.0011.0014.709.15700

7507.00&DO

20.00

10.0010.0014.0014.00

Ef110MS1702

5204

2708

2516

7716

6258.009.00

28.002200

ROME740287 170740472 122574079 &007E473 12.48740474 12.48

713

2513 7.5096344 185514412 12.90

UNEARS411001 IA .3990101/4178

Mal 588 .3014031364 .99

L043091(

FO31 1.45dosiiti 1.290131811 2.25193232 6.03741112411 .7971339 .54

1A155511

0166011

tA1700101

147093I/07233N

1172391307330118173901

LA174113014

1.81741098

U174791741174101U1741E114

1974801

111451619116116018114880

AIMED1114940I/14960A1933029

00401015134035

1/0390011

71113841

11.011C:

11002CP

11083011108401

3075373650.43

1.33130

3325.79

1.I9.IS.46.72.41.9500

Los

40120.54

1.49.09

1291.65160

VOLTS PECS CRYSTALS7895 .90 1001

7512 .90 3117815 .90 IMIC7824 .90 10686

78058 750 18431(

78125 1.50 MHZ711150 1.50 24571

711240 1.50 32761(

7955 1.10 30112

7912 1.10 01141

7915 1.10 4.430

1924 1.10 SAW

112511 1.80 EMU79128 1.00 MC731511 1.56 7.1580

79240 110 0462OIL SOCKETS 104t2

.14 10.710

.15 IBM

.17 404

.147

141416 0118111.

20 M.24 01

moos30 034011 .25 tr!

C04016 700.371.

41105 .50

16 x 2114< only £798 x 4116 only £58

3.093.703.601502001.503.052.703052.101.002.702.702702.502.702702.70290290

MSC251311500111E14411/C1441296354

CPUs

0000

120

7006

2035

810ECMmoswoo

7.505.03

12.112.9010.115

62311006.00

15.0012.958.00

100013.45MAO

W/WINP NTS

NEIL .36

14 OE

16012

18211.

25

AO

.74

.95

HOME COMPUTING CATALOGUEIf you're in town, visit our showroom inChapel Street, next to Edgware Road tubestation. We have Tritons on display plus acomprehensive range of components andaccessories, specifically for personal com-puter users. Books, mags, tapes, data, cables,plus much more. Showroom open 6 days aweek (half day Thurs from 1.30).

'ataCame.se

Clog..

TRAVOAM

Ir iII

191.

NEWA4 size catalogue

filled with ourlatest products

40p +SAEALL

PRICESEXCLUDE

VAT

V T ALL PRICESEXCLUDE VAT

TR4NSAM COMPONENTS LTD12 CHAPEL STREETLONDON, NW1 TEL. 402 8137

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

II

II

If

IIIIIIII

IIII1IIIIIII

IIII

* ***** * * *Now, complete your system

The ultimaterange of speakers

We carry a good selection ofhigh quality chassis for the DIYWeaker constructor) 12" or 15"Bau speakers and Dual ConcentricsExponential horns from E13.80,or our fabulous Pismo Horns whichhandle a 6K -20K frequency rangein any PA system up to 100W (No 0over required) and cost only E632each

Ropellghts Great enact at discos. 7metres long Multiway connectors. 4 channelC4600 (Inc pack of spare bulbs)

Bulgln Octal plugs andsockets There's always hundreds olBulgin Octal multiwey plugs and sockets in stock

ROM Squire's. Each pin rated6A. Perfect for your Sound toLight System P552 SOCKET.E0.89P551 PLUG Cl 72

Muir !way Cables4 core MA) 630/metre5 core 16A) 78p/metre6 core (6/5) 92p/metre

PERSONALCALLERS

ONLY

Citronic MM313 MixerIdea for the DIY enthusiast building up acomplete dn. system 4/6 on mono. inc,LED indicators, connections via phonosockew at rut-. Bargain price, includingPSU E89,70.

Projectors Come and see our speciallYsetected protectors from £50.60 ISqua e Multi.feet 1501 to (83 37 (Tutor IIE DISUIplus the widest array of WOW..attachment and effects that you'lleve, see on continuous clemonst11011

TurntablesOur 9nsur passed Ownexperience has enabledus lea select the best turntablesfor your requirements Forexample the new BSR P20013/11i dove ONLY C28 75

Many disco accessories

4$110,

0IfII

IIIF

IIII

II

II

AU Roger Squire's shops have a service departmentwhich carries large stocks 01 DISCO SPARES &ACCESSORIES

ALL SHOPS OPEN TUE. SATLATE NIGHT WED,UP TO 8 PMI

021o1

M32

\ O.".tSt.Ll1rniO5

.1105

On?" .3. Ab

p0"6'' .0PA"-1106 ekas aassae2o.

.61 SSA w01,"'3Conl.,,s 2 brsce,j,A

SGONost'oe

G}%--

Random Electronic

EASY DICEBuild your own 'EASY DICE' from the 5 integratedcircuits and full components supplied, including box anddescriptive instructions.

CompleteP.C.B.

ofLayout

Kit

`."-" -11 - re:n

7-

0 rT.

All you need is a soldet mg ironTWO DICE FACES TOUCH CONTROL

a Self Assemble Diceb *Ready built Dice

£3.95 plus 25p p&p

£4.75 pi. 25P P&P

Ottipr iluvv how Fringewood Electronics Ltd1 Hatton Court, Ipswich, Suffolk. 0473 210151

Amount enclosed £NameAddress

please state amount I &lulled In appi opt late bo+l-b1

NEWS:Digest

Gloss in A BoxElcometer proudly presents theGardner Glossard II, a glossmeter to let you compareshiners with one hand-held in-strument, which holds theoptical system, digital display,circuitry and rechargeablebattery.

The Glossgaid-II is availablein the popular geometries -20°, 45°, 60°, 75°, and 85° - formatt to high gloass applica-tions. Testing is to internationalstandards. The meter has a hold

button, which, guess what,holds the last reading on theliquid crystal display until yourelease the button. There is alsoa battery recharge light to warnyou that the battery is somew-hat lacking in oomph.

The instrument comes in azip -up vinyl case, which alsoholds the new precision, self -locating gloss standard, andcomes complete with a smallplug-in mains charger.

For further details of theGardner Glossgard II, get intouch with Elcometer Instru-ments Ltd, Edge Lane, Droyls-den, Manchester M35 6BU.

Flip Flory

New from Perdix is the IEE"Flip" vacuum fluorescent dis-play. It has a single line of 40characters and needs only asingle five volt supply. The highbrightness, 7 x 5 dot matrixcharacter is 0.2 in high and hasan editing cursor.

The display is controlled byan on -board dedicated proces-sor and interfaced via an 8 -bitbi-directional data bus forparallel TTL ASCII. The unitwill also accept serial data.

A unique feature is theECMA 7 character font set that

supplements the standard 96character ASC11-7 set to in-clude European characters plusupper and lower case letters,numerals and symbols.

The use of an on -board pro-cessor allows useful controlfunctions such as backspacecursor, carriage return, linefeed, horizontal scroll, readdata at cursor, read data at aspecified address, etc.

The unit is designed forlimited -space, front panelapplications. In fact, the entireassembly is less than one inchdeep (by 3" high and 10.6-wide).

For further informationplease contact Perdix Com-ponents Ltd, 98 Crofton ParkRoad, London SE4.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 17

Quartz Melody Multi -Alarm ChronoFor 1980 Try this 34 Function

Count -down ( or,Timer :3.-0003),Can be used for a host of applica-tions from boiling an egg to warningyou your parking meter is expired.The timer is presettable to 23 hours59 mins. 00 secs. in 1 min. stepsand counts down in 1 sec. steps. Itoperates quite independently of theother counters and the watch can bein any other mode whilst it is beingused.At the preset time the musical tonewill sound for 1 minute.

=A:Alarm 8.5C

The alarm can be set at 1

minute intervals to any timewithin the 24 hour period.A clears firm musical tonesounds for 1 minute at theappointed time. An automaticroll-over to the normal time is afeature after the alarm hasbeen read. A clear indicatordisplays whether the alarm isset or not.

Time Zone ( ?.08 18

The time zone enables you totell the time in two places atonce. It can be useful onholiday or business trips. Justprogramme the second timezone and it will be per-manently recorded for youreasy reference.

Chronograph inn nnnn'tiu.uuuuThis watch incorporates a sophisticated and veryaccurate stop/start counter which has many appli-cations in sporting events and timing for recordingsetc.Mode 1: Is the normal stop -watch mode. Stop -Start -Zero.Mode 2: The lap timer enables first and second pastthe post times to be recorded. The display is frozenbut the counter continues to count.Mode 3: Longer timing intervals, such as journeytimes, can be recorded whilst the watch is reading itsnormal time, or the count -down is being used. Thecounter counts to 1 hour in 1/ 100 sec. steps in allits modes

for onl £26.95

Display Format

Count downalarm indicator

Press S3 -mode selectionHold S3 -

S3testalarm sound

444 .10.1

H H HjH

111111111111111111101

1.4 Irsi Yu*

....111111011.1111111111.

(NORMAL TIME DISPLAY)

2nd time -zone indicatorAlarm indicator Chronograph

indicator

Press S1-1 light

MODEL M30

5 independent workingmodesi) Normal watchii) Count down alarmiii) Alarmiv Dual time zonev) 1/100 sec. chrono-

graph

S2 Press S2 -SEC / DATEAlternative hold S2 -

HR MIN SEC Sec to zero

A very impressive new watch at a superbly low price fromMetac. This super slim watch is only 7mm thick (that'sthinner than most mechanical tick-tocks), but its micro-processor heart packs 34 different features.

In addition to those listed on the left the watch can displaythe day of the week in French or German or English (justselect the one that suits you).

It has fast and slow setting rates for the counter and thealarm as well as the normal time setting.

There are 7 display indicators, 6 digits and a back light fornight viewing. The 5 working modes are independent of eachother, and the watch can be operated in all 5 modes at once.

FOR ORDERING INFORMATION PLEASE SEE OVER

Display indicators(not all shown)

ffiEtar ELECTRONICS& TIME CENTRES

North & Midlands67 High Street, DAVENTRY

NorthamptonshireTelephone: 03272 76545

South of England327 Edgware Road

LONDON W.2Telephone: (01) 723 4753

18 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

QUARTZ LCD5 FunctionHours. mins, secsmonth, date, autocalendar, back light,fully adjustablebracelet to fit allWrists

£6.65Guaranteed sameday despatch.

Very slim, only6mm thick.

MULTI ALARM6 Digits10 Functions* Hours. mins . secs* Month, date, day* Basic alarm* Memory date

alarm* Timer alarm

with dual timeand 5 Countryzone

* Back light* 8mm thick

£18.65

, , - e

Sr

M5

SOLAR QUARTZ LCDChronographPowered fromsolar panel withbattery back-up6 digit, 11 functionsHours, mins secs daydate. day of week1.'100th, 1/10th secs10X secs . minsSplit and lap modesBacklight. Autocalendar Only 8mmthickStainless steel braceletand backAdjustable braceletMetac Price

Guaranteed same£13.65 day dispatch M9

HANIMEXElectronicLED Alarm Clock

Features and SpecificationHour'rninute dispiay. Large LED dnplav iintnam. and alarm on indicator. 24 Hours alarm withon.'off control. Display flashing for power lassindication. Repeatable 9.minute snooze. Displaybright,dim modes control Size 5.15" e 3 93"2.36" 1131rnm llmm 6OrnmlWeight- t 43 ibs 1065 kgI.

£10.20 Thousands sold!Mains operated,

Guaranteed sameday despatch.

M13

SOLAR QUARTZ LCD5 Function

Genuine solar panelwith battery back-up. /Hours. mins . secs.Day / dateFully adjustablebraceletBack -light.

Only 7mm thick

£8.65Guaranteed same daydispatch.

MUM

FRONT -BUTTON ALARMChrono Dual Time

6 digits. 5 flags.22 functions.Constant display ofhours and mins plusoptional secondsor date display.

AM / PM indicationMonth, date.

Continuous displayof day.Stop -watch to12 hours 59.9 Wsin 1/10 second steps Fully adjustableSplit and lap timing open bracelet.modesDual time zones £22.65Only 8mm thick Guaranteed sameBack -light day dispatch

LADIES DAY WATCHQUARTZ LCD

Ladies Day Watchonly 25x 20mmand 6mm thick.fidurs, minutes,seconds, day, date.backlight and autocalendar.Elegant metalbracelet in silver orgold fully adjust-able to suit veryslim wrists.State colour pre-ference.

£9.95 daysame

day despatch

EXECUTIVEALARM WATCH6 functions plus alarmConference signal, 5minute snooze alarm.Conference signalsounds 4 secs. beforemain alarm to give ad-vance warning andoption to cancel.Snooze sounds 5 mins.after main alarm and isalways preceded by theconference signal

£14.95 M60

QUARTZ LCD11 Function SLIM CHRONO6 digit. I 1 lunct:onsHours, mins., secs., day,date, day of week.1 '100th, 1 10th, secs..10X secs., mins.

. Split and lap modes.Back -light, autocalendar. Only 8mmthick.Stainless steel braceletand back.Adjustable bracelet.

Merac Price

£1 0.65 Thousands sold,

Guaranteed same day dispatch

SOLAR QUARTZ LCDChronograph with AlarmDual Time Zone Facility6 digits. 5 flags.22 functions.Solar panel withbattery back-up6 basic functionsstop -watch to12 hours 59 9 secsin 1 /10 sec steps.Split and lap timingmodesDual time zonesAlarm9mm thickBack -lightFully adjustablebracelet

£27.95

LADIES FASHION WATCHQUARTZ LCDLady's FashionWatch. Elegantbracelet in bronze/gold finish or silvercolour. Hours,minutes, seconds,day, date. backlightand auto calendar.Adjustable for theslimmest of wrists.

State colour pre-ference.

£14.95Guaranteed sameday despatch M17

MACY QUARTZANALOGUE

Automatic calendarday and date, infinitebracelet. This man'swatch has elegance aswell as the robustappearance providedby a watch withtraditional features.Accuracy is providedby a quartz crystalpowered by a long lifeminiature battery.

£24.95

Wflifffiffie

M21

HOW TO ORDERPayment can be made by sending cheque, postal order. Barclay. Access or American Expresscard numbers. Write your name, address and order details clearly, enclose 40 pence per singleitem for post and packing or the amount stated in the advert. All products carry 1 year writtenguarantee and full money -back 10 day reassurance. Battery fitting and electronic calibrationservice is available to customers at any Metac shop. All prices include VAT currently at 15%Metac Wholesale:Trade enquiries - send for a complete list of prices for all the goods advertised plus manymore not shown also minimum order details.Telephone orders Credit card customers can telephone orders direct to Daventry (03272)76545 or Edgware Road 01-723 4753 24 hours a day

Service Enquiries: 03272-77659CALLERS WELCOME. Shops open 9.30am-6.00pm.stW

=1=1

QUARTZ LCDALARM 7 FunctionAlarmHours. mins secsMonth. date, day6 digits. 3 flagsplus continuousdisplay of dayand dateor secondiBack -light.

Only 9mm thick

£12.65Guaranteed sameday dispatch

igistg

WmM4

ALARM CHRONOwith 9 WorldTime Zones* 6 digits. 5 flags.* 6 basic functions* 8 further time

zones* Count -down alarm* Stop -watch to

12 hours 59.9 secsin 1/10 sec steps

* Split and laptiming modes

* Alarm* 9mm thick* Back -light* Fully adjustable

bracelet

£29.65 M8

LADIES COCKTAIL WATCHQUARTZ LCDLady's Cocktail WatchHighly functionalwatch which also suitsthose special occa-sions. Beautifully de-signed with a very thinbracelet which retainsstrength as well aselegance. Hours,mins.. secs.. day. date.backlight andautocalendar.Bracelet fully adjust-able to sun slim wrists.State gold or silver fin-ish £19.95Guaranteed same daydespatch M18

Metac price break-through for anAlarm Chrono-graph withDual TimeOnly 16.95

OUTSTANDING FEATURES* DUAL TIME. Local time always visible

and you can set and recoil any othertime zone (such as GMT)Also has a light for night viewing

* CALENDAR FUNCTIONS includethe date and day in each time zone.

* CHRONOGRAPH/STOPWATCHdisplays up to 12 hours. 59 minutesand 59 9 seconds.On command. stopwatch displayfreezes to show intermediate (split / lap)time while stopwatch continues to run.Can also switch to and fromtimekeeping and stopwatch modeswithout affecting either's operation.

* ALARM can beset to any time within a24 -hour period At the designatedtime, a pleasant, but effective buzzersounds to remind or awaken you,

Guaranteed same day despatch M16

FIE IBC ELECTRONICS& TIME CENTRES

North & Midlands67 High Street, DAVENTRY

NorthamptonshireTelephone: 03272 76545

South of England327 Edgware Road

LONDON W.2Telephone: (011 723 4753

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 19

SEIKO MEMORYBANKCalendar watch M354Hours. mins., secs.Month, day, date in12 or 24 hour formatall indicated continuously.Monthly calendar displaymonth. year and all datesor any selected month over80 year period.Memory bank function.Any desired dates up to 11can be stored in advance.2 year battery life.Water resistant.

...111.11114.

"veraellaile

Metac Price £79.50 M11

CASIO CHRONO95QS-3LBStainless steel case.water resistant to 66feet. Hours, mins, secs. twin_am/pm, year, month,'date, day. Auto -calendarpre-programmed untilyear 2029. 12/24 hourstopwatch function.Range 7 hours. 1/100sec. (Mode), Nettime/tap-time/ 1st -2ndplace times. Dual timefunction. Accuracy15secs. per month.Battery life approk 4years

Price £23.95 M22

BELTIMECHRONOGRAPH

9 FunctionsHours, mins, secs,day, date, month,interchange feature,automatic calendar,backlight. net time / laptime. Stainless steelbracelet. Battery life 1year.

MELODYMULTI -ALARMCHRONOGRAPH

Hours, mins. secs, day date, countdownalarm, dual time zone, 1/ 100th secstopwatch. Lap/split time, 1st and 2ndplace times Melody test function

Pnce £26.95 M30

L

SEIKO ALARMCHRONOGRAPHWith WEEKLY Alarm.Hours, mins, Secs,month. date, day,am /pm.Weekly alarm - canbe set for every day atdesignated time, e.g.6 30am on Mon..Wed and Friday.Alarm set timedisplayed above timeof day.Full stopwatchfunctions, laptime.split, etc

Price £89.95 M10

CASIO LADIES86CL-23B-1

Elegant slim line stainlesssteel bracelet, fullyadjustable. Hours, mins,10 sec. symbol second byflash, am/pm. Month,date, day. Auto -calendarpre-programmed for 28thday in Feb Accuracy permonth 15 secs., battery lifeapprox. 15 months.

Price £37.95 M23

BELTIMEMULTI ALARM

29 FunctionsHours, mins, secs.date. day. Alarm,chronograph, lightWatch 8 functions,Alarm 4 functions,chronograph 17functions. Stainlesssteel bracelet.

Pnce£29.95 M35

DUALTIME -ALARMCHRONOGRAPH

f;i'011

Incorporating module of world-famousJapanese watch manufacture. Hours,mins. secs, day of week, month, day anddate. 24 hour alarm. 12 hour chrono-graph, 1 / 10th secs. lap time. backlight,stainless steel case and bracelet, mineralglass battery hatch, long life battery

Price £35.00 M12

SEIKO MELODYALARMCHRONOGRAPH

Chiming Alarm, pluschrono. Hours, mins.secs, date, day,24 -hour alarm, 12hour chronograph,1 / 10th secs, laptimeback light, stainlesssteel, mineral glass.

Meter Price £92.95

CASIO F-200SPORTS CHRONOAttractive man's watchin black resin withmineral glass. Hours,mins, secs. am/pm.Month, date,alpha -numeric day.Auto -calendar set 28thFeb. Stopwatchworking range 1 hourunits 1/100 sec.Mode, Net time /laptime / 1s1 -2nd placetimes. Accuracyapprox. 15 secs. permonth Battery 12months

Price £15.95 M24

CASIO F -8C3 Year Battery Life

Hours, mins, secs,am/pm, date, day.Auto calendar set.28th Feb Stopwatchfunction. Accuracy 15secs. per month.Battery life approx. 3years.

Pnce £10.95 M36

PICOQUARTZMICROPROCESSORALARMCHRONOGRAPH

Multi -language - day of the week can beset to English, French, German, Italian orSpanish. Chime - every full hour com-bined with a response signal. beebing atevery pressing of the functions. Can beswitched off 12-24 hour format, backlight, Chrono - 1 full-scale chrono withlap, counting hours, up to 24 hoursMinutes, secs, 1/ 100th secs Two Alarmsystems Two time zones

pace £37.95 M32

SEIKOCALCULATORWATCH

Full specificationcalculator withmemory. plus multifunction watch.Hours, mins, secs,day, date, backlight.

Automatic calendarLong -life battery

Pnce £96.20 M27

CASIO ALARMCHRONO 81CS-36B

Hours, mins, secs,day, and also day,month and yearperpetual automaticcalendar. 100th sec.chronograph to 7hours. Net time/laptime/ 1st and 2ndplace times. Useroptional 12/24 hrdisplay 24 Alarm.User optional, hourlychime. Backlight, Pricemineral glass. stainlesssteel. Water resistant £35.95to 100ft Battery lifeapprox 4 years. M25CASIOCALENDAR 200

47CS-2313-1BlockStainless steel. Hours,mins, 10 second symbol,second (by flash),am /pm. Month, day,date. Auto calendar setfrom1901 to 2009. Fullmonth calendar display,dual time function.Accuracy 10 secs. permonth. Battery lifeapprox. 15 months.

Pnce £59.95 M37

SEIKOCHRONOGRAPH

Hours, mins, secs and day of the week.Month, date and day of the week. Stop-watch display. Hours. mins. secs up to 12hours (minutes, secs. 1/100 secs up to20 minutes). Lap timing. continuous timemeasurement of two competitors. Stain-less steel mineral glass

Price E56.00 M33

illEtaC ELECTRONICS& TIME CENTRES

North & Midlands67 High Street, DAVENTRY

NorthamptonshireTelephone: 03272 76545

South of England327 Edgware Road

LONDON W.2Telephone: (01) 723 4753

20 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

DIGITALCLOCK RADIO

soliestoikp

Mains. AM/FM /LW radio Green digitaldisplay Snooze alarm Auto switch off.Clock dimmer External FM Aerial

£19.95plus El 30 Post & Packing

M40

Credit Card sizeMemory % ect plus auto power off

£7.95

TV GAMES

Affitigh.Black & White or Colour4 game. 2 ball speed, 2 ball angles, 2battery sizes. Tennis. Hockey. Football.Handball. Practice

£11.95 Colour£8.95 B/Wplus 54p Post & Packing

M48

RADIO/CASSETTE3-Band/LW-MW-FM

Auto stop. DC6V. AC Power 220V Built-,' condenser microphone High poweroutput

M52

RADIOCONTROLLEDCARFormula One Racer4 fumbon forward reverse steering left to ugh,No wires remote control

£19.95 M56

Portable LCDClock Radio

* Back -light* Batteries supplied free* Quartz crystal controlled

£17.95M41

Digital Clock/Alarm/Calculator/Stopwatch

Calculator with % and memory. Con-tinuous clock with hours, mins.. secsday. month, day of week. Alarm, Stop-watch, split -time 1 year battery. Leather-ette wallet

£17.95 M45

TV GAME WITH GUN

Colour. 6 games. Moving target. FootballTarget. Tennis, Squash, Practice. Batteryor main

£17.95plus 11 25 Post & Packing

M49

RADIO /CASSETTE1 -Band/ MW

Condensor microphone. Battery or ACPushbutton key operation. Auto levelcontrol Retractable handle Eject equipment

£17.95plus { 2 00 Post & Packing

M53

MODEL CARRADIOScale model car incorporatingsingle band radio. Excellentquality sound with clew-, de-sign of controls incorporated inthe car components

£5.95 M57

DIGITAL CLOCK LCDTravel

Hours. mins 24 hour time and AlarmSnooze timer. Large 12 5mm displayNight light Size 120mm x 74mm19mmWeight 120 grams

£17.65M42

LCD CALCULATORSCIENTIFIC

8 -digit mantissa 2

digit exponent elecIronic calculator on one

single chip.

111 FBI our111111111111111P

11111111,11011111111111

000001O 0000O 0000O 0000

Functions -SIN, COS. TAN. SIN -1 COSTan -1, SINN, COSH, TANH, ex, 10x LeLog, Vx, 1 /x.

Statistical functions£16.95 M46

AIR FRESHENERElectronic

Timer can be set to emit nice smells whenrequired or running permanently toremove really bad smells Batteryoperated

Price £4.95M50

I--MAINS/BATTERYPortable Radio

/11.1106.1116.6.

4 Bands. LVV/MW/SW,FM Teak fin,case

£19.95plus 85p Post & Packing

M 54

ELECTRICCAR AERIALSonlx automatic motorantenna. 5 sections. Onemeter in length. Excel-lent value at

£10.95

QUARTZ ANALOGUECLOCK TRAVEL

Mini Quartz Alarm clock Complete withtravel pouch. Features loud alarm andoperates from 11/2 volt battery

£9.95M43

LCD CALCULATORCASIO MELODY 80

Full calculator spec 3 independentmusical alarms time stop -watch, count-down timer

£23.95M47

DIGITALCLOCKLED Display.Features Hours/mins.Display Alarm with snooze.Mains operated excellent valuefor money. Compact size only 6in x 21/2in x 3 in

£6.95M51

AIRCRAFT RADIO

AM 'FM?,, es Police/Aircraft frequencies

;,'ration. Retractable aerial

£9.95M55

CAR RADIO/CASSETTE2 band car radio /stereo cassette player Long andMedium waveband coverage Rotary controls formuN/volume tone balance and tuning Pushbutton control for cassette curt and fast forwardwind Output 7 x 3 Watts (music) 17 volts

£34.95 M59

IlletaC ELECTRONICS& TIME CENTRES

North & Midlands67 High Street, DAVENTRY

NorthamptonshireTelephone: 03272 76545

South of England327 Edgware Road

LONDON W.2Telephone: 101) 723 4753

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1 980

KIRLIANPHOTOGRAPHYUnexplained phenomena on the fringe of established sciencehave attracted a great deal of interest this century, but there isstill no plausible theoretical framework to explain the observedevents.

Two groups of phenomena that have come closer toexplanation than most are first the observations andphotographic records of mysterious lights and radia-

tions around people and objects - called variously,radiation field photography, electrophotography, Kirlianeffect, Human aura, St. Elmo's fire plus other names - andsecond acupuncture.

The Kirlian effect and acupuncture would seem asrelated as monkeys to stones but, as will be shown, they doseem to be complementary concepts. Belief in the existenceof the human aura is very ancient. Medieval peopledistinguished four kinds of aura: 'Nimbus' and 'Halo' thatstream from the head, 'Aureola' that issues from the wholebody and 'Glory' which is both kinds combined. Thesewere often featured in paintings. Others divide the aura intohealth, vital, Kharmic, aura of character and aura ofspiritual nature.

Some people (clairvoyants particularly) claim to be ableto see these effects without aids. The colours of the auraindicate the person's emotional and physical state.

The Old Testament bible relates how Moses was in-volved with a burning bush. Similar flames appeared as the"tongues of fire" that came upon the twelve apostles onthe day of Pentecost.

Sharp ends of extended objects - ships masts, yard-arms, church steeples, airplane wingtips - in free air oftenexhibit this mysterious fire. This became known at St.Elmo's Fire after the martyred Italian bishop who becamepatron saint of sailors. Other names used include Castorand Pollux, Dioscuri, Corpusant and Fermie's Fire.

Recently this is said to be static electric discharge -corona discharge. A bluish glow was photographed aroundPete Conrad the astronaut, when he landed on the Moonfrom Apollo 12 in 1970.

We all have, no doubt, experienced being charged -up ondry days. There are recorded instances of people who havethe ability to deliver powerful electric charges who alsohave electro-magnetic properties enabling them to suspendmagnetic materials.

Electrical storms have been known to produce images,(a rainbow in one case and pictures of people in others)semi -permanently formed in glass window panes. This iscalled lightning photography.

In psychic photography, photographs of people,sometimes of people long departed, have appeared onplates. It is suggested that there exists another energy form

Kirlian photograph of an oleander flower. The flesh of the flowerin contact with the photographic film is indicated by the darkportions.to electro-magnetic radiation. It is usually called bio-energy, the name coined by Czechoslovakian para-psychologists.

Electro-photographyElectro-photography is as old as the availability of photo-graphic emulsions that could record the existence ofradiations. A case dated 1842 is the oldest. YakovNarkevich-Todko showed photographs taken using elec-trical discharges in 1898. A 1926 book by C. Hall"Triumphs of invention," contains "A photograph of theEiffel Tower taken during the dispatch of wireless time -

22 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

FEATURE

signals. The ultra -violet radiations, although invisible to thenaked eye, appear luminous on the photographic plate."

This kind of detection has become known as Kirlianphotography after release of the work, in 1958, of theRussians Semyon and Valentina Kirlian. At first, interest inthe Western World was minimal but it gained followersespecially from 1970 onward.

In the West, one man responsible for assisting thisinterest to flourish is Kendall Johnson, who, it seems, wasthe dominant person in the US to obtain Kirlian pictures ofobjects. ("The Living Aura" by K. Johnson, HawthornBooks, New York, 1975, is a must to read.) There weresome earlier accounts of success in the US - one waspublished it 1938.

Kendall Johnson's first radiation field photograph, taken in 1971using surplus electrical parts. The subject was a leaf.

Having accepted that there is little mysterious in Kirlianphotographs, researchers are now concentrating on tryingto resolve whether or not the pictures have recorded morethan mere electro-magnetic radiation effects. Do theycontain evidence of bio-energy? Does some new form ofenergy exist to be explained?

The Practice of Kirlian PhotographyIn the simplest form of electrophotography, an unexposedphotographic film is placed on top of an electrode plate withthe emulsion uppermost. Onto this is placed the subject tobe photographed - a coin, leaf or person's finger or hand.High voltage is applied to the top of the object anddischarged through the object and photo -emulsion to theother plate. Clearly the high voltage source must not be oflethal extrent if used directly on the body.

Body -part photographs can be made using the staticcharge built up on a person who shuffles around on asynthetic carpet in a dry room. The use of any other activevoltage source for bodypart pictures can be a most dange-rous practice. It is strongly advised that you experimentwith objects such as leaves, coins, flowers, metal shapesand liquid drops, unless you know about the safe use ofelectrical sensing equipment in electro-medical applica-tions.

OBJECT FOR IHICHKIRLIAN PHOTOGRAPH

IS DESIRED

I

°HAL 1 CHAHG11) 10HIGH HOL1/101 011

GROUNOI II

1Hit AHL A OFCONIACI WILLHI 1111:0RDI 0

ILM Me 1AL PLAT.

LSJOIII SIDE UP.11L/l,R0l1NO OR HIGH

VIR 'AGE POWl H SUPPLY.

ION

Fig. 1. A simple method for making Kirlian photographs of fingertipsusing static charge built up on the body.

Photographs can be obtained using DC charge, a burstof audio frequency high voltage or a single short pulse. Justabout every combination appears to have been tried.Finding the right combination of film type and speed andsource characteristics apparently can be time consuming aseach object will need different settings. Results have beenobtained using Tesla coils without and with spark -gaps (inwhich case RF is generated), Van de Graaf generators,charged capacitors and the charge of a person. Wei, in apaper in the Journal of Applied Physics, Volume 47, p.4437-4441 reported using a proprietry electric photo-graphy set made by Edmund Scientific. This providesvoltages up to a maximum of 20W in the frequency range3-50 kHz. The set allows the user to vary voltage,frequency, pulse width, pulse repetition frequency, andtime. He also found that a spring -release piezo-electricgenerator, which supplies a 10 uS pulse of 19 kV, wassuitable as a source for his work with metal grids. It is likelythat the larger style piezo-electric gas lighters might suffice.Wei used ASA 3000 film (Polaroid 87) in his work.

FILMCASETTE

OBJECT PLACEDIN HERE

PULLEY

FILMCASETTE

SIMPLE CAPACITORDEVICE

Fig. 2. Roll film can be used to record a Kirlian image. This methodrequires complete darkness to make the exposue.

Boyers and Tiller (J. Appl. Phys., Volume 44, 3102-3112, 1973) typically used 100 uS pulses of bipolar 1

MHz signal having amplitudes varying from 20 to 100 kV.They derived this by driving an Oudin resonator coil (detailsgiven in their book) from a modified radio transmitter. Theyfound that each pulse produced different streamer con-figurations, these tending to expose the film uniformlywhen a string of pulses was used as excitation. They alsoestablished that the surface composition, smoothness,topography, inter -electrode spacing and parallelism ofelectrodes were each important factors having bearing onthe results obtained. They also experimented with colourfilms, effects produced depending very much on themethod of use and the type of film used.

A description of how to build a simple set of equipmentis given in Johnson's book "The Living Aura." Anotherwork "High voltage photography" by H. S. Dakin,

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 23

published by Edmund Scientific Company, Barrington,New Jersey, USA in 1975 provides circuitry details.

Many different arrangements of film and object positionhave been used. The film speed number - the ASA or DINrating - is of little value as the energy exposing theemulsion is quite different from that for which the film-

speed rating is assessed. Different films produce differentresults.

METALELECTRODES

RF PULSEGENERATOR \

DIELECTRIC SHEET(EXPOSED PHOTOGRAPHIC OBJECTFILM)

EMULSIONSIDE DOWN

MECHANICAL SUPPORTSLID OVER SANDWICH

50t. SPACE

FILM (EMULSIONSIDE TO OBJECT)

ELECTRODE

FILM

NON OPTICALLYTRANSPARENT ENVELOPE

-OBJECT

ELECTRODE

Fig. 3. Two methods of enclosing film to produce Kirlian photo-graphs in a lighted room.

Defined EffectsMany variables exist to alter the characteristics of a Kirlianeffect photograph. Even so, certain effects appear to havebeen established, giving electrophotography an intriguingnature.

It is said that live leaves and small animals produce amuch clearer image, of higher contrast, than when they aredead - the energy image is said to reduce as the leaf loosesits life.

Another claim is that a piece torn from a leaf still showsas present in a photograph of the remainder. This is termedthe phantom or cut -leaf effect. (This is not be be lightlydismissed, for in the image storage method of holographythe hologram plate can be broken and any piece from anyposition will still produce the same complete 3-D image).

OBJECT

fi

200,1 THICKDIELECTRIC BLOCK

H T

FOCUSSINGELECTRODES

GENERATOR

LUMINESCENTSCREEN

Fig. 4. A cathode ray tube arrangement for displaying a picture ofthe field around the object being examined.

The Kirlian aura of a live scorpion. The live parts in the centre of theoutline are portions of the arachnid's abdomen in contact with thephotographic plate.

It is also said that psychic healers' finger pads produce amore brilliant image when healing is in process comparedwith when it is not. As Johnson states: "Do the imagesshow an energy transfer between healer and subject? Isthere some informational exchange going on, resulting inthe different energy representation of the finger pads."

This also is quite plausible for we accept that informationcan only be transferred in a physical system when anenergy (or mass) carrier exists to convey the data.

Evidence, in the form of Kirlian photographs, has beenobtained implying that people with "green -thumbs" haveproperties that assist repairing damaged plant tissue.

Electro-photographs are certainly artistic and oftenpleasing to behold. Perhaps they do demonstrate someform of energy unknown to man.

AcupunctureWhat in the world have electro-photography and acupunc-ture in common? Why stage an international conference onthis joint theme? The first Western Hemisphere Conferenceon "Kirlian Photography, Acupuncture and the HumanAura" was held in New York City in 1972. Papers wereread by authors from the Soviet Union, Canada, France,

24 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

FEATURE: Kirlian Photography

Japan, United Kingdom, Eire and the United States. Letterswere received from Czechoslovakia and other countries.

Kirlian photography is concerned with the properties ofobjects to modify and transmit energy fields - which arecertainly of electro-magnetic kind - but may also be ofsome other, yet unexplained, information -linking nature.

Acupuncture is a Chinese art of healing, using needlesinserted into the body at certain places called acupuncturepoints. It is a very ancient art and has been continuouslypractised, with effect, in the Asian regions.

The Western attitude to medicine and healing has, untilrecently, been sceptical towards acupuncture because itcannot be aciequately explained by Western science.Considerable evidence now proves that there is much aboutthe body that can be controlled. Yogis are able to performquite amazing variations of bodily function. Somehow theinsertion of needles, in various numbers, places and depthscan cure many ailments.

Bio-feedback is an apparently 'understandable' techno-logy. Brendan O'Regan, of the Design Science Institute,Washington DC., wrote in 1 973:

"Presumably, we in the West believe our senses only astheir impressions are verified by the machines we create."It is in this light that Kirlian photography relates toacupuncture as well as to many other subjects.

The Kirlian aura of a seafern.

Radiation field of a 'Jewel of the Ocean' starfish. Fine structure ofthe field is evident at the extremities of the creature.

Several workers have reported that Kirlian effects areespecially intense over known acupuncture points. Fur-thermore, some people have built probes - called tob-iscopes - that indicate their position.

It is claimed that acupuncture can be established bymoving electrodes over the body and observing the signalprocessed by an electro-physiological high -gain amplifier.The extent of the reading is said to also indicate the energylevel of that particular acupuncture energy circuit. A 1971Russian tobiscope, by Adamenko detects skin resistancechanges that are claimed to drop from around the normal1M down to 50-100 kilohm at an acupuncture point.

Related Reading"Psychic discoveries behind the Iron Curtain"' S. Ostranderand L. Schroeder, Prentice Hall, 1971."Galaxies of life - the Human Aura in Acupuncture andKirlian photography" S. Krippner, Interface, New York,1973."Photography records electrical phenomena." ElectricalConstruction and Maintenance" Volume 75, 86, 1967."Instant imaging of electric, radio and acoustic fields" W.G. Hyzer, Optical Engineering, Volume 17, SR -3, 1978."Handbook of Unusual Natural Phenomena" W. R. Cor-liss, Sourcebook Project, Glen Arm, USA, 1977. E" T1

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 25

electronics todayWhat to look for in the February issue: on sale January 2nd

CMOS 555Now you all know about the CMOS version of the 555 timer chip - because we told youabout it last month in Designers Notebook, so no excuses in the back row please.

Only thing to do now was to get Tim Orr, the country's leading circuit man, to spend afew eons playing with the device and produce one of his superb circuit filled features allacross ETIs pages next month. This is good stuff of the highest quality. Be there with yoursoldering irons, there are circuits for just about everything under the sun - and if we canfind a heater element big enough we'll see you with a design for one of them next year.

ONE FIVE THREE SEVENWhatdeyer mean that you've never heard of this? Of courseyou have. It's a brilliant Voltage Controlled Attenuatorthingy for which Keith Brindley will explain at least a million

\ applications and designs next month. Well, not actually amillion but quite a few. He also gives you a breadboarddesign to go away and do your own things with. What morecould you possibly want? Stand up the boy in the back whosaid "Felicity Kendal".

CASIO FX502P/FA1The best thing since sliced bread. Honest. If you don'tbelieve us read our comprehensive report on this tenprogram 256 step, 100 label, cassette jumping calculatorand music adaptor in next month's ETI.

The abacus will never again.

MODULAR SYNTHESISERNext month ETI presents a new series of syn-thesiser circuit modules which represent theforefront of modern music technology. Not onlythat but they're a bit new as well. And somewhatof a departure for us. The complete design will bea sophisticated machine comparable to the verybest available today at any price and with morefacilities than the Playboy Club.

However we are aware that not everyone has ause for such a machine, and that there are a largenumber of you out there who wish to experimentwith sound effects circuits, without the require-ment for a fully fledged synthesiser system. AndSo . . .

Our latest machine will be presented inmodular form, with each separate unit mountedon a 'front panel' assembly, and housed in acommon box. As the PSU requirements will bestandardised, you can build as many - or as few- of these superb designs as you need when youneed them.

CASSETTE HEADDEMAGNETISER

Sometimes we're so ingenious we amaze ourselves! Andsometimes we're so dumb we amaze everyone else.

Apart from that though this is a good idea - demagnet-ising your cassette player heads reduces all the nasty thingsthat you don't really wanna hear anyway and makes thosethat you do sound even better.

Ours naturally has something a bit special about it -something that makes it both easy to use and moreeffective. But we're not gonna tell you what cos we wantyer to buy next month's magazine instead!

VMOS 2M PAOne for all the hams of this world. Put some POWER in yourwords with our VFET Power Amp. Based on the latestcircuit techniques this is a design to burn out the receiversof the universe. Don't just broadcast - BROADCAST withETI!

SIGNAL TRACERThis is instead the only way to find that sinewave that wentinto that phono socket half an hour ago and hasn't comeout yet.

For the sake of all lost waveforms everywhere build thisone.

26 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

B.K. ELECTRONICS

Stereo Cassette Tape Deck Assembly.Comprising of a moulded lop panel assembly andtape deck mechanism coupled to a record/playback printed board assembly. for installation intocabinet of own choice (separate power amplifierrequired(.

Spetilication Pause control, solenoid assistedauto slop. 3 digit tape counter. DC motor withelectronic speed control. twin to meters.normal/chrome tape switch. twin Mic inputsockets. AC erase system.Tape Speed 4.8 ems, sec.Input Sensitivity For OdB rel. level0.25mv t 3013

Input Impedence 2.26 Ohms.Output level To both lilt and right handchannels 160 my 2dB

Output Impedence - 6.8K Ohms.

Signal/Noise ratio 45 dB (Nominal).Harmonic Distortion 2°. !Nominal}Note Power supply requirements 9 volt ACand 24 volt AC transformer fir,r supplied.Size Tape Mechanism 4',m x 6'.m x II hin

Approx. Top Panel 13 x 9 fin Approx

Price - E25.00+E2.50 P&P.

Mail Order Only

AM/FM Stereo Tuner Amplifier chassis[originally designed for installation inio a music tends]Beady built. comprising of a tuner pre -amp. board and

separate power supply/power amp. board.Note Interconnection wiring diagram supplied.Rotary Controls Tuning. on/elf volume. balance. treble.bass.

Push-button Controls Mono. Tape. Disc. A.F.C.. F.M.

[VHF(. LW. MW. SW

Power Output 7 walls AMS per channel. al better than 2°.TN into 8 ohms. 10 watts speech and music.Frequency Response 60Hz-20KHz within 346

Tape Sensitivity Output - typically 150 my. Input - 300my for rated output.Disc Sensitivity 100 my (ceramic cartridge)Radio FM 61119 8T.5MHz-108MHz.Long Wave 1451thz-265101z.Medium Wave 520KHz-1620KHz.Short Wave 5.8MHz-I6MHz.Size Tuner - 2afin. x I5in. x 7 in Approx. Power Amp -

2m. a 7 fin. a 4' dn. Approx.240 volt AC operation. Complete with circuit diagramPrice - E22.00 + E2.50 P&P.

B.K. ELECTRONICS37 Whitehouse Meadows, Eastwood, Leigh -on -Sea, Essex

LINES FROM OUR VAST STOCKS - IMMEDIATE DELIVERYNEW STOCKS BELOW MANUFACTURERS'PRICES. Postage & packing add 50p per order.CALCULATOR CHIPS General InstrumentGIMT4 on anti -static foam 24 pm D I. L socket forWe web 8owrnar display E1.50 se Pack of 25Mau E26. 100 for ESO. 500 for £350.DISPLAYS by Hewlen-Packard. Seven segmentC4.707 (5082.77501 95p. Common anode halfinch red &Way brand new in maker's cartons 6for E5. 50 for 70p ea. 1000 for 115p eeeh.TBA 120A TV IC amplifier Siemens 55p. 10for E13, 100 for E80, 1.000 for E360.B ECKMAN 500 ke Triggerable clockingocelot°, for use with calculator chips 5v supplywith circuit C1, 10 for fit. 100 for OHLB URROUGHS S DIGIT Pommies calculatordeploy 7 segment 0.25" diens. Neon type withred bevel socket end date. E1.95 ea. 10 for E17,100 for E140.HONEYWELL PROXIMITY DETECTOR inte-gral amplifier 8v D.C. E3.50 se 10 for 30.MULLARD 11A800. LC audio amplifier 1113pesoh, 10 for ES, 100 for E70. 500 for £300.RCA CA30119. F.M. IF CI SO, 10 for C12.RCA CA3090A0. F.M decoder 2.50, 10 forE20, 100 for E175.BU 205 MULLARD, E1.50 se, 10 for E12, 100for E100.2N3065 80V version T03 power IC for £3.50,100 for E21, 500 for 125, 1.003 for E200.BU208 003 Texas T V power transistors E1.75.10,10 for £15, 100 for E120, 1.000 for C1 se.MC1310P-11N76115N F M stereo decoderE1.20 sech, 10 for El es, 100 for 85p es.MULLARD A01111AD182 Matched pairs 1

par 80p, 10 parrs ES, 100 pairs LSO.Canons of 600 parts E250 EX -STOCKRADIATION DETECTORS Guam FibreDosimeters Pen type with clip with lens and scale0-50R. Originally over E5 OUR PRICE 96pEACH. 10 for £1. 100 for CIO. 1.000 for E600.CLOCKING OSCILLATOR (PysDynamics),thick film 1mHZ supply 5v 192548mm 86p. 10for £7, 100 for NO. 500 for E250.TV TUNERS by Mullerd U.H.F. 38 ones site'33/4,12,4)0 1/4 E2.50 es. 10 for E20. 100 forE175. 500 for E710. 1.000 for E1,250.M D TUNER MODULES with dataLP1171 combined AM /FM IF strip E3.60. LP1179 FM front end with AM tuning gang, usedwith LP1171 E3.50. LP1171 and 79 pair E5.75,10 pars for EfilL 100 parrs for 400.CA30115 RCA POSITIVE VARIABLE REG.5volt 100m amp variable 1.8-24v 55p es. 10 forE5. 100 for E35. 1,000 for E300.MULLARD lllll 7 AM tuner modules withcloud 2.50 es, 10 for E20, 100 for E175.LUSTRAPHONE RIBBON MIKE E1.50, preamp on chess's 3x2x lm 10 for £12.150.TAA116111 (14 pin DIL) IC TV sound and FMamplifier -detector by ATES on to circuit board with

KENNEXPORT ORDERS add lO'r for carriage

other parts. Complete with data & connections60p. 10 for E5. 100 for 40p es. 500 for 35peedl.AVO-8 METER MOVEMENTS for milltaryversion Precision 37.6 micro -amp (50sa withintegral shunt) movement E10.50.

TV SOUNDHigh guilty IV sound horn your Hi-Fi Simplyplug into aerial socket of your FM tuner. 01.150(UK P&P 50p)As reviewed by "Popular Hi-Fi". July '79.

PHOTO CONDUCTIVE CELL E1.25. Highpower Cds cell 600 mw for control Circuit,.Reststance 800 ohm to 4K. Max volts 240. Sint

1/2in. 10 for C11, 100 for E100.DYNAMIC MICROPHONE. tow imp. Fosterinsert. 0.45, 10 for E11, 100 for E100.UHF TUNER SY GEC. 38mc/s with slow motiontuning Site 5 x 3 x 2m. £3 N. 10 for E25. 100for E220, 500 for E1,000.TWO GANG MINIATURE VARICAP TUNER500pf with tuning knob, sue 3 x 11/2 x 1 Vein,£1.25...10 for 10, 100 for ES5.ATES U14552 AUDIO LC. AMPLIFIER 14PIN D.I.L 300m wens lip seek 10 for 14.50.100 for I215.

13 ELECTRIC 2+2 watt I.C. afore°audio chips with circuit & data E1.115 moth.RCA CD402PAE 16 pin D I.L presenage updown counter 85p wish, 25 for 1E15, 100 forESO, 1.000 for E355 In anti static tubes of 251U.H.F. TV TUNER (preamp) with 6E180 Sipeach. Built on P C board 2 X 2in (sold withoutdata) 10 for E4.50, 100 for E35, 1,000 for E250.MARCONI LC. Oscillator Dahl (7099 can) 30psash, 10 for E2, 100 for £15, 1.000 for E126.PLESSEY 5L432A I.C. IF &moldier (T099 can)116p seek 10 for ES, 100 for E311, 500 for 0160.V.H.F. MODULATORS for TV games 55p each.2 transistor -on built P C sixes 242411/4in 10for E4, 100 for E35, 500 for E150.R.F. Filters for above modulators 20p sash withcomponents and cods on built p circuit. sue2 x 2 x 11/4in 10 for 03.50,100 for C30, 500 forE125.HIGH VOLTAGE TV TRIPLER DIODES BYI.T.T. stick type per 10 £1.60, per 100 E18, per1.000 £S5.TRACES ATES coinage regulators Sip sash, 5volts 100 m /amps (7099) per 1014.50, per 100E39, per 1.000 E280. 12v TBA625A also16 PIN low profile D I .L sockets 12p, 10 for El,100 for CB, 1.000 for Sp each.THYRISTORI Motorola 2145061 0.8 amp 60volt 16p, 10 for 115p, 100 for 13p, 1.000 for 1 1pmesh.IN 914 TYPE DIODES tested. uncoded in boxesof 1,000 E10, r0 000 for E75, 100.000 forE500.

11/ All mail to:5 404 Edgware Road r-,.4c_c.7London W2 England or=iejPhone 01-723 1008 li

TELEX 262284. REF 1400

All theseadvantages...

Instant all-weather starting Smoother running Continual peak performance Longer battery & plug life Improved fuel consumption Improved acceleration/top speed Extended energy storage

..in kit formSPARKRITE X5 is a high perforimil iductivedischarge electronic ignition system designed I 111 1.181:110111CS

D I Y. world. It has been tried. tested and proven to be utterlyreliable. Assembly only takes 1 2 hours and installationeven less due to the patented 'clip o i easy fit 1 iii

The superb technical design of theSparkritecircuit eliminates problems of thecontact breaker There is no mtsiin due ti i

contact breaker bounce which isellininati.i Ielectronically by a, pulse suppressR ncircuit which prevents the unit firing if Owpoints bounce open at high R P MContact breaker burn is eliminated tyreducing the current by 95^,, of the fun nt

There is also a 1,1111(1111)4)XIINHIf 41 dwellcircuit which allows the coil a Honda rperiod of time to store its energy lwfordischarging to the plugs The 'Ind IIbuilt cat static: timing light system,, tunctiulllight, and security changeovi,i switchWillwork all rev counter s

Fits all 12 v negative -earth vehicleswith coil/distributor ignition up. to 8 cylinders.I HE KIT COMPRISESEVERYT HINGNEEDEDDie pressed case Ready drilled itlismiliniMextrucledbase and heat sink, coil mounting clips and accessories All kitcomponents are guaranteed for a period of 2 years from date ofpurchase Fully illust rated assembly and installatiolinstructions eraincluded

Roger Clark the world famous rally driversays "Sparkrote electronic ignition systemsare the best you can buy-

ift all'UMWHIGH PERFORMANCE

t z.er ELECTRONIC IGNITION

roElectnics Design Associates, Dept. ETI /182 Bath Street, Walsall, WS1 3DE. Phone: 109221614791

Name

Phone your Order with Access or Barclaycard

Inc VAT and PP OUANTITY ROT

X5 KIT £16.95ACCESS OR BARCLAY CARD No.

I endow chequelPEFt 40,

Creque No.

Send SAE if brochure only required.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 27

The professionalscopesyou've always needed.

Super 6

When it comes to oscilloscopes, you'll have to go a long way toequal the reliability and performance of Calscope.

Calscope set new standards in their products, as you'll discoverwhen you compare specification and price against the competition.

The Calscope Super 1 0, dual trace 1 0 MHz has probably thehighest standard anywhere for a low cost general purposeoscilloscope. A 3% accuracy is obtained by the use of stabilisedpower supplies which cope with mains fluctuations

The price 21 9 plus 1 7.52 VAT.The Super 6 is a portable 6MHz single beam model with easy

to use controls and has a time base range of 1ps to 100ms/cmwith 1 OmV sensitivity. Price 1 62 plus El 2.96 VAT.

CALSCOPE DISTRIBUTED BYMaplin Electronics Supplies LtdP.O. Box 3Rayleigh, Essex.Tel: 0702 715 155Mail Order

Watford Electronics,33-35 Cardiff Road,Watford, Herts.Tel: 0923 40588

Audio Electronics,301 Edgware Road, London W.2.Tel: 01-724 3564Access and Barclay card facilities(Personal Shoppers)

CALSCOPESuper 10

'Now Converted to 50H2 forUK TV'

SUPERBOARD II£188÷w

Full 8K basic and 4K user RAMBuilt and tested

Features Uses the ultra powerful 6502 microprocessor 8K Microsoft BASIC -in -ROM Full feature BASIC runs faster than currently available

personal computers and all 8080 -based businesscomputers

4K static RAM on board expendable to 8K Full 53 -key keyboard with upper -lower case and user

programmability Kansas City standard audio cassette interface for high

reliability Full machine code monitor and I/O utilities in ROM Ditect access video display has 1K of dedicated memory

(besides 4K user memory), features uppercase, lowercase, graphics and gaming characters for an effectivescreen resolution of up to 256 by 256 points. NormalTV's with overscan display about 24 rows of 24 charac-ters, without overscan up to 30 x 30 charactersExtras

Power Supply & modulator £29.50 + VAT 610 Expansion board with 8K ram and dual

drive miniflopp chip £188 + VAT IP CD3P minifloppy disk, cased and with

power supply £312 + VAT Injection moulded case within 6 weeks 4K Ram upgrade kits £35 + VAT

TusUs unD

We are dealers for the rest of Ohioscientific range of computers. Thewidest range produced by any micro-computer manufacturer, thisincludes:-

C2 - 4P A professional 4K basic in -ROM computer cased and withpower supply

C2 8P DF A 32K basic in ROMcomputer with dual 8" floppydiskdrives for serious personal andsmall business use

C3 - OEM A 32K computer with3 micro -processors (6502, 6800,Z80) and dual 8" floppy disk drives

Full business, word sprocessing andcate base management is availablefor all disk based systems.

Write for catalogue for further details

4 MORGAN STREETLONDON E3 5AB

Software

Tapes at £5.50 + VATHomonyms*, Counter', TrigTutor, Bar Graph, DefiniteIntegral, Basic Math, Presidents',Powers, Electronics Equations,Spelling Quiz, Solar System,Continents, Add Game, MathIntro, Base Ten Converter, MathBlitz`, Inventory Demo, RatioAnalysis, Advertisement,Statistics I, Salary Demo',Annuity 1, Annuity II, Intereston Loans, Loan Finance,Uneven Cash Flows, PersonalDestroyer, Hide & Seek, StarWars, Black Jack, New YorkTaxi, 23 Matches, Lander',Etch -a -Sketch, Space War ' ,

Battleship*, Crytography.Tapes at £7.30 + VAT:-Hangman, Mathink, Trend Line,Straight & Constant Depreciation,Address Book', CheckingAccount, Savings Account, Bio-rhythm, Hectic.Tapes at £11.00 + VAT:-Word Processor**, ProgrammableCalculator, Tiger TankBasic Tutor Tape:- £26.40+VATAssembler editor with Manual

£25 + VATExtended monitor with Manual

£10 + VAT

TELEPHONE:01-981 3993

TELEX:261426 ATN. LOTUS SOUND

29 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

PROJECT

MOVING COILPREAMPLIFIER

A design of the highest fidelity, styled to match ouramp, which is capable of bringing the best from those mobilewindings.

Over the last several years therehas been a dramatic increasein the number of moving

coil cartridges released. The design ofthis type of cartridge results in anumber of advantages which workson a moving magnet princple.

The pick-up coils are reduceddrastically in size and weightcompared to the coils used in movingmagnet cartridges. This results in atotal cantilever weight that is muchsmaller than in the typical movingmagnet cartridge. Since the weight isgreatly reduced the ability of thestylus to react to transients is in-creased and an overall improvementin signal accuracy results. Moving coilcartridges generally have superiorfrequency response characteristicsand improved phase response at highfrequencies. But they also have dis-advantages.

The small pick-up coils have a verylow impedance resulting in much

lower signal levels than available fromnormal phono cartridges. In fact, thevoltages present on the typicalmoving -coil cartridge at a recordingvelocity of 10 cm /sec can be in theorder of 1 50p V! This is generallyinsufficient to drive an amplifier toanything like full power. Furthermore,since the output level is some 30 dBbelow that expected by the amplifierthen a great reduction in the signal-to-noise ratio will result. An amplifierwith a short circuit signal to noise ratioof 80 dB for example, which is quite agood figure, will end up with a signalto noise ratio of about 50 dB - whichis distinctly bad.

The internal impedance ofmoving -coil cartridges is around 5ohms and to achieve the low recom-mended load impedance required it isclearly not satisfactory to simply loaddown the input of the average phonoinput with a resistor since this doesnothing to overcome the signal -to -

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

noise ratio problems.The solution to these problems is to

insert some voltage gain between theoutput of the cartridge and the phonoinput. This can be done in two ways.Firstly, it is possible to use a trans-former to boost the voltages up to thedesired level and they are capable ofvery good results. But, transformersare still limited to transient perfor-mance and noise. To obtain thenecessary voltage gain the turns ratiomust be relatively high. Since theimpedance ratio is related to thesquare of the turns ratio, the outputimpedance must, of necessity, behigh also - usually around 30 k for a500 input impedance. This is sub-stantially higher than the outputimpedance of normal phono car-tridges and degrades the noise figureof the phono input stage. A solution tothis is to use a pre -amplifier instead ofa transformer to achieve thenecessary voltage gain.

29

INPUT

Cl3n3

R21OR

Fig 1. Full circuit diagram ofmoving and pre -amp. PSUshown below.

R19108

A4 C122100

R271k

013

e8131390c

R21 R25= 56OR 2208

015 4-AAAA-4BC549

-04BC559

b

C3470p

C4470p

05-08BC549

eb

NOTEONLY ONE CHANNEL IS SHOWN.

COMPONENT NUMBERING ON 2nd CHANNELSTARTS AT 101 e.g. R101,R102, C101,C102

R23330R

R24330R

R20IOR

C13it 100

C

C14

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LED

5 PIN DINPOWERSOCKET

LED2REDLED

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411111ac01480140

Above right: Internal view ofone of our prototype units.

30

SKI+ 0 2I Po 0

3

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:C151000

R41k

R52k2

C522

C622

R62k2

R8108

R9270R

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R112k2

C910

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2200p

R10 R12270R 2k2

R1718R

R1818R

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SPECIFICATION

R15390R

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H46390R

Gain 28dB ,x25 approxj.Frequency response 29Hz to 48kHz± 1dB.Input impedance Adjustable 3.3 to 100 ohms.Noise Total equivalent input noise 0.3nV y. Hz.

Over a 20kHz noise bandwidth -42nV.Signal-to-noise ratio, with respect to aninput level of 1500V: -71dB.

Total Harmonic distortion With respect to an input level of 0.2mV,unmeasurable;below noise) Calculated tobe 0 001 5% see text). Rising to 0.015%for a 3OmV input signal at 1 kHz.

Channel separation Better than 61dBInput overload margin Better than 80dB.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

PROJECT: Moving Coil Preamplifier

HOW IT WORKSThe input stage consists of Q1 to Q8 plusassociated circuitry. Q1 to Q4 and Q5 to Q8are in parallel to reduce the current densityproviding a low input impedance stagehaving very low noise.

The required low input impedance canbe achieved in several ways. Firstly, we canmake the input stage a common base con-figuration. In this type of circuit the inputis connected to the emitter of the transistorso that the input impedance is determinedby the emitter resistor in parallel with thebase -emitter junction of the input tran-sistor, which can be quite low. However,this does not solve the problem of inputstage noise.

The other possibility, and the one weelected to use in this design, is commonemitter configuration. The impedance of thebase -emitter junction of a bipolar transistoris a function of the amount of current flow-ing in the emitter of the transistor. This willbe largely determined by the collectorcurrent and not by the base current, whichwill contribute only a small amount of thetotal emitter current. A study of base -emitter junction is approximately equal to:

263

le (mA)

where 'j3' is the small signal current gain ofthe transistor, and 'le' is the current in theemitter of the transistor in mA.

So, to reduce the input impedance of thefirst stage it is simply necessary to increasethe emitter current. But this increases thecurrent density in the input transistors,increasing the noise generated by the inputstage.

To understand why this happens it isnecessary to look more closely at the causesof noise.

NoiseThere are two main sources of noise in tran-sistors: shot noise and I/F noise. Shot noiseis the main cause of noise at middle andhigh frequencies and is generated when anelectron attempts to cross a potentialbarrier. It is therefore directly related to theamount of charge flowing in the device.More specifically, it is given by the equa-tion:

1s2 = 2qidcB (amps)2

(mean shot noise current)where 'q' is the charge of an electron, incoulombs, 'ide' is the DC current in amps,and 'B' is the noise bandwidth in Hz.

I/f noise has a random amplitude likeshot noise but its spectral density has a I/fcharacteristic. This means that the noiseamplitude increases as frequency decreasesand becomes the dominant source of noiseat low frequencies. As with shot noise, itsequation reveals that it is directly relatedto the current flowing in the transistor.

2 ic_jgadda=

where 'Idc' is the DC current in amps 'K'and a are constants that are a function ofthe particular device. 'f is the frequency inHz, and 'B' is the noise bandwidth. Noticethat as Itic is increased, so too is the 1/fnoise (1f2).

It is clear from this that, in order to keepnoise generated by shot and I/f noise to aminimum, it is necessary to keep the currentdensity in the input stage low. But, as wesaw earlier, to obtain the necessary lowinput impedance we have to increase theemitter current. The solution to this is touse several transistors in parallel to form theinput device. This decreases the currentdensity in each of the transistors since thenecessary emitter current can be shared byall of the input devices. It also places theimpedances of the base -emitter junctionsin parallel, further decreasing the inputimpedance of the first stage. Furthermore,since each transistor is a completely inde-pendent noise generator their noise voltagewill tend to reduce each other (a processtoo complex to examine in detail here).

This configuration works very well andthe noise levels of this preamplifier rival anyof the commercially available units.

To see just how difficult it is to obtaina satisfactory signal to noise ratio at thesesignal levels it is necessary to look' at ano-ther form of noise called 'thermal noise'.This is caused by the agitation of chargedparticles in any conductor due to theirtemperature. Every passive componentwill generate thermal noise and short ofdunking the whole thing in liquid heliumto cool it off, there is simply no way of get-ting rid of it. Thermal noise is given by theequation:

eR2 = 4kTRB volts2

where 'T' is the temperature in degreesKelvin (K).'R' is the value of the resistance.'B' is the noise bandwidth'k' is Boltzmans constant, equal to 1.38 x10'23 W-sec/K.

From this equation we can calculate thetheoretical noise that will be generated bythe moving coil cartridge itself. This clearlyis the absolute lowest noise figure that ispossible with the input stage generating nonoise of its own (which is very unlikely!).

If we let the temperature of the tran-sistor be 300 Kelvin (i.e.: mean atmospherictemperature) and the noise bandwidth be20 kHz (the hi-fi audio band), then since theDC resistance of the cartridge is about 5ohms the equation becomes:

eR2 = 4 x (1.38 x 1043)x300x5x(20x103)

Therefore eR = 4.07 x 104 volts or 41 nV.

So, the thermal noise of the cartridge itselfis 41 nV.

Actually, this calculation is not quiteright since the noise bandwidth is defined ashaving a 'brick wall' response. An amplifierwith 3 dB point of 20 kHz that is falling ata rate of 6 dB per octave will actually havea noise bandwidth much greater than 20kHz. Furthermore, if we want to be able toquote noise figures to enable comparisonbetween different input stages, it is valuableto quote noise voltages independently ofnoise bandwidth. This can be done quiteeasily by dividing the noise voltage by the

square root of the bandwidth. The dimen-sions of this new figure will be "volts perroot Hz", and our result for the thermalnoise of a moving coil cartridge becomes:

41nV/VHz

N/20 000or 0.29 nV/VHz

Now, if we are aiming at a signal to noiseratio of 70 dB with respect to a signal vol-tage of 150 nV (0.15 mV), which is theexpected signal level at a recording velocityof 10 cm/sec., then the equivalent inputnoise of the amplifier will be given by theequation:

N-70 = 20log(

0.15x104

and is equal to 0.33 nV/./Hz.The necessary equivalent input noise is in

the same order of magnitude as the noisebeing generated by the cartridge itself!

The total equivalent input noise of thisunit was measured at 0.3 nV/ x/1 -1z. Withrespect to a noise bandwidth of 20 kHz, thiscorresponds to an input noise of 42 nV,giving a signal to noise ratio with respect toan input signal of 150 nV (0.15 mV) of 71dB. At this level, the noise generated by thecartridge itself will be one of the dominantnoise sources.

Capacitor Cl and C2 fix the upper fre-quency roll -off characteristics as well asshunting the input with the desired loadcapacitance for the moving -coil cartridge.The configuration of RI and R2, Cl and C2was found to give the best loading for avariety of moving -coil cartridges.

The potentiometer RVI allows the inputimpedance to be varied over the range mostcommonly recommended by cartridge man-ufacturers.

Negative feedback is applied via the net-work consisting of R28, capacitors C5 andC6 and resistors R5 and R6. Some degen-erative feedback for the input stage isapplied to the first stage by the emitterresistors R7 and R8. Capacitors C9 and CIOare coupling capacitors to the second stagewhile bias for this stage is determined byR11, R12, R13 and R14.

The power supply consists of a seriesregulator Q13 and Q14. The potentialdividers R21/R23 and R22/R24 divide thevoltage present at the output of the regu-lator and drive the transistors Q15 and Q16,and the LEDs. The transistor base -emitterjunction in series with the LED will dropOV6 + I V65. Therefore, whenever thevoltage present at the centre of the poten-tial divider tries to increase above 2V3the transistor incteasingly, conducts de-creasing drive to the pass transistors Q13and Q14.

This is a relatively low no:se regulatorsince the voltage reference is LED and nota zener diode which is a noisy device. Resi-stors R19 and R20, together with capacitorsC12 and C13 form 6 dB per octave low-passfilters on the supply rails to further reducenoise that may be generated by the regu-lated supply...

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 31

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PROJECT: Moving Coil Preamplifier

Preamp RequirementsPreamplifiers have their disadvan-tages also. The biggest problem by faris the design of an extremely low noiseinput stage with the correct inputimpedance to load the cartridgeaccording to the manufacturers'recommendations. The distortionmust be kept to a minimum and thefrequency response should be as flatas possible. These design goals arenot unique to a moving coil cartridgepreamplifier but they are difficult toachieve owing to the very low outputvoltage of the moving coil cartridge.

The required low input impedancecan be achieved in several ways.Firstly, we can make the input stage acommon base configuration. In thistype of circuit the input is connectedto the emitter of the transistor so thatthe input impedance is determined bythe emitter resistor in parallel with thebase -emitter junction of the inputtransistor, which can be quite low.However, this does not solve the pro-blem of input stage noise.

The other possibility, and the onewe elected to use in this design, iscommon emitter configuration. Theimpedance of the base -emitter junc-tion of bipolar transistor is a functionof the amount of current flowing in theemitter of the transistor. This will belargely determined by the collectorcurrent and not by the base current,which will contribute only a smallamount of the total emitter current. Astudy of base -emitter turn -on charac-teristics shows that the impedance ofthe base -emitter junction isapproximately equal to:

2613

le (mA)

where '13' is the small signal currentgain of the transistor and 'le' is thecurrent in the emitter of the transistorin mA.

Performance FeaturesThe total equivalent input noise of thisunit was measured at 0.3nV/ 1/ Hz.With respect to a noise bandwidth of20kHz, this corresponds to an inputnoise of 42nV, giving a signal to noiseratio with respect to an input signal of1 50nV (0.1 5mV) of 71 dB. At thislevel, the noise generated by the car-tridge itself will be one of thedominant noise sources.

The circuit uses a symmetricalconfiguration with NPN and PNPtransistors set up in such a way thatasymmetrical distortions tend to can-cel. Normally distortion products aregenerated differently for positive andnegative signal excursions and thistends to produce second harmonicdistortion products. The configurationused in this circuit results in very lowsecond and third harmonic distortion.This has enabled a total harmonicdistortion figure of around 0.0015%to be obtained.

The problem with quoting distor-tion figures of this order is that theyare too low to be measured directly,being well hidden under the noiselevel. The only way a figure can beobtained is to remove the overallnegative feedback, measure thedistortion and then divide by the gaindifference when the feedback is reap-plied. Unfortunately, feedback doesnot affect all the distortion productsequally, but the figure is still mean-ingful.

Another advantage of the symme-trical design of the input stage is thatit does away with the need for aninput capacitor. This is a definite ad-vantage when dealing with low inputimpedances since the value of thecapacitor would have had to be verylarge to obtain a flat frequency res-ponse at low frequencies.

The signal voltages present in thepreamplifier are naturally extremelylow and for this reason the powersupply has been kept as a separateunit to reduce the possibility of 50Hzinduction from the power trans-former.

A voltage regulator supplies thenecessary ±6V. As it is critical toachieve low noise it is important thatthe regulator does not put noise ontothe supply rails which would degradethe noise performance of the unit.Normally the voltage reference usedfor regulators of this type is a zenerdiode but, as the zener is reversebiased, it generates a comparativelylarge amount of noise. In this designan LED was used as the voltage

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

reference. A red LED operated in theforward -biased mode drops a con-stant 1V65 and generates very littlenoise.

ConstructionConstruction is relatively straightfor-ward since most components aremounted on the board. Other con-struction methods are possible butperformance will not match that of ourprototype.

Mount the resistors and capacitorsfirst, followed by the transistors. Cutthe necessary lengths of shieldedcables and solder them onto the boardkeeping the ends as short as possible.Solder the necessary lengths of hook-up cable to the board and afterchecking all components mount theboard in the chassis.

Use a steel box if you can, if not,just be careful where it is placed.

Once the board is mounted in thechassis, the pots and rear panel hard-ware can be mounted and the wiringcompleted according to the wiringlayout diagram shown. The shieldedcables coming from the outputs onthe board have only one of theirshields connected to the outputsockets which are wired together andconnected to the chassis at theground terminal.

It is important that the sockets beinsulated from the case and that theground connection made to them isaccording to the wiring diagram. If theunit is going to be used with therecommended power supply thereshould be no hum problems. It iswired so that the 0 volt line is notconnected to the chassis of the powersupply. This is important, otherwise ahum loop around the units' mainsgrounds will result. Do not 'cure' theproblem by disconnecting the groundwire at the 240 volt plug as this willremove any ground connection fromthe power supply chassis. This isdangerous.

Powering UpBefore turning the unit on make a finalcheck of the board. Check the orien-tation of the transistors, electrolyticand tantalum capacitors and theLEDs. If all is right, turn down thevolume control completely and switchthe power supply on. The LEDs in thepreamp's regulator should come onimmediately.

Perhaps we are biased, but thesound quality of this preamp is ex-tremely good! Eli

33

THREE FOR FREEFROM CSC4/

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For the full detailed instructions, including-Electronics by Numbers- circuit diagrams, simply

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If you missed Free project No's 1, 2 and 3, please tickthe appropriate box in the coupon.

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Expiry date

If you missed project No's 1, 2 and 3.

PBS 63C

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inn INN 1=1 MN =II =I En ...... JTel: Saffron Walden 10799) 211382. Telex: 817477

Project 1: Two -Transistor Radio. Pro -

111

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34 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

BACK IN BUSINESSDORAM ELECTRONICS LTD, a name well known in the home electronics market, areback in business under new management. We aim to combine our many years experiencesupplying components worldwide with personal service to our new customers.

NEW PROJECT PACKS:

Universal Digital - This versatile unit can replaceanalogue meters with an fsd from 1 to 100 V or10mA to 1 Amp. Three 7 -segment LED display.

£14.65+ Touch Tuning - Can be used with most varicap

tuned front ends to select up to 9 pre-setchannels. Digital channel display. £17.80

+ DJ Killer - Detects the sound of a voice on theradio and cuts off the audio until music is

transmitted. £7.65

VAT inclusive prices. Postage add 40p

COMPONENTS We stock a large range of TTL. CMOS,Linear and Microprocessor IC's, plus Transistors, Diodes,Resistors and Capacitors etc.

PROJECT PACKS We can supply 'Project Packs'

containing all the electronic components, PCB andinstructions for over 100 different magazine projects. Theserange from simple circuits suitable for the beginner to veryadvanced designs, like our user -programmable TV GAMESCOMPUTER system.

PRICE LIST For our new Price List senc a large SAE to :

Doram Electronics Ltd., Dept ET, Fitzroy House, MarketMarket Place, Swaffham, Norfolk. PE37 7QH.Tel: Swaffham (0760) 21627. Telex: 817912

A DE BOER COMPANY

PORTABLEPRECISIO

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The LMM-200 is a compact handheld multimeter with0.5% basic accuracy and 15 different ranges. It measuresAC/DC voltage from 0.1mV to 500V, AC/DC current from0.1,u.A to 2 Amps and resistance from 0.111 to 2W /. 200hour battery life.

The LMM-2001 is an identical instrument but with a0.1% basic accuracy.

The LMM-100 is suitable for field or bench use. It has abasic accuracy of 0.1% and 25 different ranges. Itmeasures AC/DC voltage from 0.1mV to 1KV, AC/DCcurrent from 0.1µA to 2 Amps and resistance from 0.112 to20Mi2. Battery life is over 2,000 hours. It also features aunique 'digital hold' facility and adjustable carrying handle.

Lascar Electronics Ltd., Unit 1, Thomasin Road, Basildon, Essex.Telephone No: Basildon (0268) 727383.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

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LMM-2001 44.95 1.00 6.89 52.84

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JEST LEADS 1.95 0.25 0.33 2.53,

To: Lascar Electronics, Unit 1, Thomasin Road, Basildon, Essex.

Please send me Data ElLMM-100 £82.17 'Li LMM-200 £41.34 1-1 LMM-2001 £52.84 n TEST LEADS £2.53

Name

Address

I enclose cheque/P.O. value--------- MCII#3

NASCOM-2+FREE16K RAMHere's an offer you can't refuse:

Because of the lack of availability of MK 4118RAMs, Nascom Microcomputers is supplying itsNascom 2 without the 8 spare 4118s but with a FREE

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So, for £295 plus VATthis is what you get:

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Z80A which will run at 4MHz but is selectable between1/2/4 MHz.HARDWARE Industrial standard 12" x 8" PCB, through hole plated, masked

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REVOLUTIONARY TOUCHOther features keyboard TRULY SOLID STATE Built-in electronic shift lock. Two -key rollover to prevent accidental two -key operation

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EXPANSION NASCOM-1*Expansion buffer board £32.50MEMORY KITS (inclusive allhardware)

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36 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

FEATURE

DESIGNER'SNOTEBOOK

In this month's 'Notebook' Ray Marston looks atapplications of the ubiquitous CD4093B CMOS IC.

Regular readers of ETI and our sister magazine HobbyElectronics will have noticed that the project designteam have a special affection for the CD4093B

CMOS IC. This device is a quad 2 -input NAND Schmitttrigger. It is a highly versatile package that can be used in awide variety of wave -shaping, timing, logic and waveformgenerating applications. This month's 'Notebook' is de-voted exclusively to describing applications of this uni-quitous device.

Schmitt ApplicationsFigure 1 shows the functional diagram and truth table ofthe CD4093B. Each of the four gates is individuallyaccessible and can be used as either a normal NAND gate or

4

A

- 14 Odd OUT13 TO 18V .Vel

0--13

12 A B OUT

110

10 0

0

vs&01/1

Fig 1. Functional diagram and truth table.

an inverting Schmitt trigger by using the connectionsshown in Fig. 2. All unused inputs of the package must betied to the positive or negative supply rails, as appropriate.

Vdd

L409313

'N 0-la}rj7 2-

go

= IN

Fig 2. Method of connecting a NOR gate for inverting Schmitt use.

Fig 3. Simple Schmitt trigger with DC input.

!cid

OUT

OUT

Fig 4. Simple Schmitt sine/square converter.

dd

R V110k OUT

SENSITIVITY

IN

V

Fig 5. Improved sine/square converter.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 37

ADO

IN

IN

A -

OUT

Fig 6. Connecting the 4093 as a rising edge detector.

IN

VDD

OUT00938

DV OUT

Fig 7. Rewiring Figure 6 to produce falling edge detection.

VDD

IN

A

IN -

OUT

Fig 8. Pulse delay using a 4093.

Figs. 3 to 5 show basic ways of using a CD4093B gateas a Schmitt trigger. Each gate has a typical hysteresisvoltage ,difference between the upper and lower triggerthreshold voltages) of 2 V when powered from a 10 voltsupply. In Fig. 3 the input signal is direct coupled to thegate input. In the Fig. 4 sine/square converter circuit theinput signal is AC coupled and the input pin is biased athalf -supply via R1 and R2. In the improved sine/ squareconverter circuit of Fig. 5, the input pin bias can beadjusted to mid -way between the upper and lowerthreshold values, to give maximum sensitivity.

Edge DetectionFigs. 6 to 9 show a variety of ways of using the 4093 todetect or delay the edges of input pulse waveforms. TheFig. 6 circuit gives an output pulse on the arrival of therising or 'leading' edge of an input pulse. The duration of

VDD

OUT

IN

OUT

Fig 9. Leading edge delay circuit for the 4093.

Fig 10. A basic astable multivibrator circuit.

GATEOUT

GATE -I I-OUT -11111/1i-

Fig 11. A variation giving gated astable multivibrator operation.

the output pulse is determined by the C-R values. The Fig.7 circuit produces an output pulse on the arrival of thefalling or 'trailing' edge of an input pulse. The Fig. 8 circuitdelays the entire input pulse by a period determined by theC-R values. The Fig. 9 circuit delays the leading edgeonly.

Clock CircuitsFigure 10 shows how a single CD4093B gate can be usedas an astable multivibrator or 'clock' generator. This circuitgives excellent performance with very clean output edgesthat are unaffected by supply line ripple and other nasties.The operating frequency is determined by the C-R valuesand can be varied from a few cycles per minute to 1 MHz orso. The circuit action is such that Cl alternately chargesand discharges via R 1. Cl can be a polarized component.

38 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

FEATURE: Designer's Notebook

Fig 12. An astable with a non -symmetrical mark -to -space ratio.

OUT

CONTROLVOLTAGE

INPUT

Fig 13. A special purpose astable. The voltage Vin has to rise aboveSchmitt (upper) threshold for operation. Frequency increases with

RI100

/c

PRESS RELEASE

Fig 14. Using a 4093 to obtain a 'noiseless' push button switch.

Figure 11 shows how the basic astable can be gated onand off via an external signal. Note that the circuit is gatedON by a high input, but gives a high output when it is in theOFF state.

The basic astable circuit of Fig. 10 produces an in-herently symmetrical output waveform. The circuit can bemade to produce a non -symmetrical output by providingthe timing capacitor with alternate charge and dischargepaths, as shown in the circuits of Fig. 12. The Fig. 12circuit produces a fixed M /S (mark -space) ratio output.

Figure 13 shows a special-purpose voltage -controlledastable which operates only when V,0 rises above the upperSchmitt threshold: the operating frequency then rises as V,,is further increased.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

Vdd

OUT

Fig 15. Touch switch giving output HIGH on operation. ReversingR1 and SW gives output LOW on operation.

SE I

Fig 16. A latching or bistable touch switch circuit using twoCD40939 ICs.

MiscellaneousFig. 14 is the circuit of a 'noiseless' push button switch,which produces a clean output pulse each time PB1 isoperated. C1 charges up rapidly when PB1 is closed butdischarges slowly .,with a period that is long relative tonormal noise spikes) via R1 when PB1 is released.

The output of the Fig. 15 circuit goes high when theinput contacts are touched. Fig. 16 shows the circuit of alatching or bistable touch -activated switch. ET1

39

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Resistors - 'OW 5% carbon film, thesevalues only: 220R, 470R. 1k. 3k9, 4k7.33k, 47k. 220k. 18R Allot E4 per 1.000(min qty of one value) or £35 per 10.000any mixAll other values from 1R to 1 OM @£11100. £7.10/1000 per value.INVERTERPrepare for the Power Cuts! Ready builtinverter. 24V DC 290x55x37mm In. willpower 6x8W fluorescent tubes. Circuitsupplied Only £2.90.

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POWER DARLINGTON PAIRPlastic power (TOP66 case) transistorstype BD695A/BD696A. Just look at thespec!! 70W BA 45V - Hfe 750 @ 4A!!Special low price - £1.20 per pair.

TMS48110 RAM4096 bit dynamic RAM with 300nsaccess time: 470ns cycle time; single lowcapacitance high level clock i /p; fully TTLcompatible; low power dissipation. Sup-plied with data £2.75.

BUZZERS. MOTORS & RELAYSZ401 Powerful 6V DC. all metal construc-tion. 50mm dia x 20mm 70p.Z402 Miniature type. 3-9V. only 22-150 16mm. Very neat 65p.Z450 Miniature 6V DC motor, highquality type 32mm dia X 25mm high, with1 2mm spindle. Only El.Z451 12V high torque motor 30mmdia x40mm high, with 10mm spindle,65p-2452 6V DC motor with gearbox givingfinal shaft speed 700 rpm. Spindle isthreaded OBA. Ex -equip El.Z453 As above but 300 rpm and un-threaded spindle £1.A372 Audible Warning device - solidstate circuit drives high efficiency trans-ducer to give high output. Voltage reqd4-18V. Can also be driven direct from TTLor CMOS. Module size 45 x 21 x 12mm.Comprehensive data supplied £1.50.

W892 Heavy Duty 12V relay, ideal for caruse -single 15A make contact. Coil 25RIn sealed metal can with mounting bracket85p.

BUY A COMPLETE RANGE OFCOMPONENTS AND THESE

PACKS WILL HELP YOUALL PACKS CONTAIN FULL SPEC. BRAND NEW.MARKED DEVICES - SENT BY RETURN OFPOST. VAT INCLUSIVE PRICES

COOL 50V ceramic plate capacitors 5% 10 ofeach value 22pF to 1000pF. Total 210 E3.51.1(002 Extended range. 22pF to 0.10F 330values 13.53.1(003. Polyester capacitors 10 each of thesevalues 0 01 n 015 0.022, 0.033, 0.047.0 068. 0 1, 0 15, 0.22, 0 33, 0.47xF. 110altogether for E5.07.KOOS Mdar capacitors min 100V type. 10 eachall values from 1000pF to 10.000pF Total 130for E4.013.1(007. Elenrolyt. capacitors 25V working. smallphysical sue 10 each of these popular values 1.2 2, 4.7, 10. 22. 47. 1000F Total 70 for E3.55.1(008. Extended range. as above, also including220 470 and 1000,F Total of 1041 for E6.06.1(021 Miniature carbon film 5% resistors C112bor similar 10 of each value from lOR to 1M E12series Total 610 resistors E5.15.1(022 Extended range. Total 850 resistors from1R to IOM E5.50-1(041 Zener diodes 40OrnW 5% 8Z1'88. etc 10of each value from 2.7V to 36V E24 series. Total280 for E16.37.

VU METERSVoo2 Twin type 2 metres 40x 40mmand driver board, supplied with circuit andconnection data, £3.50.Voo3 New type, just in. Twin typemoulded in one piece, 80 X 40mm (nodriver board but suitable circuit supplied)£2.50.

40

. ,DE Of Design of -.."ior

a .Di V Dt9ital p, ti, 04 019. Digital Compute

ViS1

i 041 Eli Electronicsand94 8 Book tt,, to Lo Logic

904: : 1,1,

.., ,.

Microcomputers are coming - ride thewave! Learn to programMillions of jobs are threatened, but millions morewill be created through the microcomputerrevolution. Will YOU sink or swim? Be one of thepeople who welcomes computers and the end ofboring jobs.Learn BASIC - the language of the small computer and themost easy -to -learn computer language in widespread use. Teachyourself with a course which takes you from completeignorance step-by-step to real proficiency - all you need to startwith is a knowledge of simple arithmetic and the use ofdecimals. And you don't need a computer.This unique course comes as four A4 books, written by threeauthors well-known in the fields of microcomputing, self -instruction and writing clear English. In 60 straightforwardlessons you learn the five essentials: problem definition,flowcharting, coding the program, debugging, and preparingclear documentation.Every lesson has thought -provoking questions and we never askfor mindless drudgery. You will know that you are mastering thematerial and feel a rare satisfaction. Harder problems areprovided with a series of graded hints, a unique and reallyhelpful approach. So you never sit glassy -eyed with your mind ablank. First time through, you may need to read most of thehints, but you will soon learn to tackle tough programmingtasks - such as writing programs for computer games, preparinggraphs on an output printer, calculating compound interesttables and estimating costs.

COMPUTER PROGRAMMING INBASIC £7.50Book 1 Computers and what they do well; READ, DATA, PRINT; powers, brackets,variable names; LET; errors; coding simple programs.Book 2 High and low level languages; flowcharting; functions; REM anddocumentation; INPUT, IF...THEN, GO TO; limitations of computers, problemdefinition.Book 3 Compilers and interpreters; loops, FOR...NEXT; RESTORE; debugging;arrays; bubble sorting; TAB.Book 4 Advanced BASIC; subroutines; string variables; files; complex programming;examples; glossary.

THE BASIC HANDBOOK £11.50This best-selling American title usefully supplements our BASICcourse with an alphabetical guide to the many variations thatoccur in BASIC terminology. The dozens of BASIC 'dialects' inuse today mean programmers often need to translateinstructions so that they can be RUN on their system. TheBASIC Handbook is clear, easy to use and should save hours ofyour time and computer time. A must for all users of BASICthroughout the world.

FORTRAN COLORING BOOK £5.40"It you have to learn Fortran land no one actually wants toassimilate it for the good of the soul) buy this book. Forget theothers -this one is so good it will even help you understand thestandard, dense, boring, unintelligible texts." New Scientist.

A.N.S. COBOL £4.40Covers the most widely used computer language in businesstoday. It teaches how to write a COBOL program and compile iteffectively, paying proper attention to spelling, punctuation, andformat.

%

THE ALGORITHM WRITER'SGUIDE £3.75FLOW CHARTS Er ALGORITHMS help you present: safetyprocedures, government legislation, office procedures, teachingmaterials and computer programs by means of YES and NOanswers to questions.The Algorithm Writer's Guideexplains how to: define the questions, put them in the bestorder and draw the flow chart, with numerous examples shown.All that students require is an aptitude for logical thought. Size:A5, 130 pages. This book is a MUST for those with things tosay.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

Cambridge LUnderstand Digital ElectronicsIn the years ahead the products of digital electronics technologywill play an important part in your life. Calculators and digitalwatches are already commonplace. Tomorrow a digital displaycould show your vehicle speed and fuel consumption; you couldbe 'phoning people by entering their name into a telephonewhich would automatically look up their number and dial it foryou.

These courses were written by experts in electronics andlearning systems so that you could teach yourself the theoryand application of digital logic. Learning by self -instruction hasthe advantages of being faster and more thorough thanclassroom learning. You work at your own pace and mustrespond by answering questions on each new piece ofinformation before proceeding.

After completing these courses you will have broadened yourcareer prospects and increased your fundamental understandingof the rapidly changing technological world around you.

earning EnterprisesSELF -INSTRUCTION COURSES

DIGITAL COMPUTER LOG ICAND ELECTRONICS £7.00Digital Computer Logic and Electronics is designed for thebeginner. No mathematical knowledge other than simplearithmetic is assumed, though the student should have anaptitude for logical thought. It consists of four volumes - eachA4 size - and serves as an introduction to the subject of digitalelectronics. Everyone can learn from it - designer, executive,scientist, student, engineer.Book 1 Binary, octal and decimal number systems; conversion between numbersystems.Book 2 AND, OR, NOR and NAND gates and inverters; Boolean algebra and truthtables.Book 3 Positive ECL; De Morgans Laws; designing logic circuits using NOR gates.Book 4 R -S and J -K flip flops; binary counters, shift registers and half adders.

DESIGN OF DIGITAL SYSTEMS£11.50Design of Digital Systems is written for the engineer seekingto learn more about digital electronics. Its six volumes - each A4size are packed with information, diagrams and questionsdesigned to lead you step-by-step through number systems andBoolean algebra to memories, counters and simple arithmeticcircuits, and finally to a complete understanding of the designand operation of calculators and computers. Contents include:

Book 1 Octal, hexadecimal and binary number systems; conversion between numbersystems; representation of negative numbers; complementary systems; binarymultiplication and division.Book 2 OR and AND functions; logic gates; NOT. exclusive -OR NAND. NOR andexclusive -NOR functions; multiple input gates; truth tables; De Morgans Laws;canonical forms; logic conventions; Karnaugh mapping; three -state and wired logic.Book 3 Half adders and full adders; subtractors; serial and parallel adders; processorsand arithmetic logic units IALUsI; multiplication and division systems.Book 4 Flip flops; shift registers; asynchronous and synchronous counters; ring,Johnson and exclusive -OR feedback counters: random access memories I RAMs) andread only memories IROMs).Book 5 Structure of calculators; keyboard encodirg; decoding display data; registersystems; control unit; program ROM; address decoding; instruction sets; instructiondecoding; control programme structure.Book 5 Central processing unit (CPU); memory organization; characterrepresentation; program storage; address modes; input/output systems; programinterrupts; interrupt priorities; programming; assemblers; computers; executiveprograms; operating systems and time sharing.

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1

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CAMBRIDGE LEARNING ENTERPRISES, UNIT 16.RIVERMILL SITE, FREEPOST, ST.IVES, HUNTINGDON,CAMBS PE17 4BR, ENGLAND.TELEPHONE: ST.IVES (0480) 67446All prices include worldwide postage (airmail extra)If order comes to £15 or more, deduct £2Please allow 21 days for deliveryGUARANTEE No risk to you.If you are not completely satisfied your money will be

refunded when books are returned in good order.

Please send me the following books:Computer Programming in BASIC (4 books) at £7.50The BASIC Handbook at £11.50FORTRAN Coloring Book at £5.40A.N.S. COBOL at £4.40Algorithm Writer's Guide at £3.75Digital Computer Logic & Electronics (4 books) at

£7.00Design of Digital Systems (6 books) at £11.500 -Level English Language (3 books) at £7.00

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ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 41

EPROMPROGRAMMEROnce you've developed and debugged a program foryour trusty Triton, transfer it to tape or into EPROMusing the latest addition to Triton's hardware - anEPROM Programmer.

THE EPROM programmer is con-structed on a single sided PCB.As there are not many com-

ponents on the board construction isquite straightforward. Start by insert-ing the wire links into their respectiveholes. There are five of these. Baretinned copper wire can be used. Theninsert pins for all of the connections toTriton and for the transformer out-puts. Now solder the normal ICsockets into position (leave the zeroinsertion force socket for now). Solderone socket to the board at a time inorder to ensure that all of the pins areconnected. As usual, start with thelargest socket and work down to thesmallest. You can now solder theresistors, capacitors, diodes and tran-sistors into position. Take care toinsert the correct value componentinto each position and to ensure thatthe transistors, diodes and electrolytic'capacitors are the right way round.Lastly insert the socket for the EPROMand solder it. The control lever isadjacent to pin 1.

It is now time to make up the con-necting cable for the board. The pro-grammer is intended to be pluggedinto the end of the Triton motherboardand derives most of its power fromhere. However, it could be run directlyfrom the extender socket on the mainboard with some care. More on thislater. Using the wiring diagram cffigure 5, attach the wires to the 64way socket and to the PCB. If you areusing a cover on the socket,remember to pass the wire through itbefore soldering both ends! Take care,when connecting the wires to ensurethat none of them become crossed ontheir journey from the socket to thecircuit board or you will end up with adata encrypted When the job is com-plete and checked, insert all of the ICsinto their relevant sockets and checktheir orientation.

The unit can now be mounted intoa box and the transformer connected.Firstly, cut a hole in the lid of the boxfor the zero insertion force socket.Also cut a slot at the join of the lid andbase of the box for the cable entry.The board should be mounted withstand-off pillars to the box lid so thatthe programming socket is flush withthe front panel. The connecting cableemerges via the slot cut between thelid and base of the box.

Firm CommitmentThe programmer is now ready for use.Connect the 64 way socket to the endof your motherboard and switch theTriton system on. Now apply 240V tothe programmer. If you are using theLevel Six firmware, you are ready togo. Otherwise it is necessary to key inthe program given. Having keyed itin, save it on tape. Now enter theprogram that you want to burn intoEPROM. This can either be doneusing the monitor or TRAP. Normally

the program is loaded from a cassettetape having been previously deve-loped and debugged in RAM. Whenan object code form of the program isready in RAM, you can start to pro-gram the EPROM with Level Six typeZ. With other monitors, load the tapewhich you dumped earlier into RAMand type G1600. In response to theSTART: prompt type the address inRAM where the 1K byte block of datafor the EPROM starts. After typing thecarriage return, the program will startto load the data into the EPROM.Before each programming pulse oc-curs, the data is read from the EPROMand checked against the new data forthe location to ensure that a 0 bit isnot trying to be programmed to a 1. Ifthis test fails a PROGRAM ERROR isreported on the VDU and program-ming is halted. On the last program-ming cycle, the data in the EPROM isread again and tested to see if it is thesame as the data being programmedinto that location. This test is used toverify that the data has been correctly

42 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

PROJECT

24VAC

+11V -5V

Fig 1. Component overlay for the TritonEPROM prograrrener

transferred and if it fails, a READERROR is reported. When an EPROMis successfully programmed, typicallyafter about 100 seconds, the FUNC-TION prompt reappears. Using theLevel Six monitor and the toneoscillator facility will cause a bleep tobe sounded.

Banishing The BugHaving successfully programmed anEPROM and plugged it into the Triton,some new bug in your program maywell decide to rear its head! Fortun-ately with EPROMS this is no prob-lem. Having traced the bug anddecided how to correct it, turn yourTriton off and remove the offendingEPROM. Place it in an eraser for about30 minutes. The eraser is just a sourceof ultraviolet light so if you do notown one of these (relatively expens-ive) machines do not worry. If youhave a sun lamp, it is a goodsource of UV light. Put the EPROM ona piece of conductive foam oraluminium foil and place it under thelamp. Remember - DO NOT LOOKDIRECTLY AT THE SOURCE OFULTRAVIOLET LIGHT - IT WILLDAMAGE YOUR EYES. If you do notpossess a sun lamp, a UV tube can be

.19V

Fr lOR 2-7

VVTI RESET

8255

PARTS LIST

AO

AllOR

RESISTORS all %W 5% SEMICONDUCTORSAl 22k IC1 8255R2,8 4k7 IC2 74LS123R3,4 10k IC3 74 LS30R5 33k IC4 74 LS33R6 47R IC5 7805R7 180R Q1,3,4 BC548R9 560R Q2 BC558R10 100R D1-4,6 1N4001R11 130R D5 27V 1W zener

D7 12V 400 mW zenerD8 5V1 400 mW zener

CAPACITORSC1 100n ceramicC2 10n ceramicC3 220u 63V electrolyticC4 47u 25V electrolyticC5 470n ceramic

purchased for a few pounds. Connectit up with a choke and fit it into the lidof a small lightproof box. Place theEPROM in the box about one inchfrom the tube, close the lid and switchon. After about half an hour you havean erased EPROM. While waiting forthe EPROM to clear, load the programback into RAM from tape and modifyit. When the EPROM and program areready, reprogram the EPROM.

If you do not have a motherboard itwill be necessary to wire up the 64

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

MISCELLANEOUS12-0-12 V 50 mA transformer,100 mA fuse and holder, 64 pinEuro Socket (straight), 40 pin ICsocket, 16 pin IC socket, 14 pin ICsocket (2 off), 24 pin zero insertionforce socket, case to suit, PCB(Transam Components Ltd).

way connector to suit the expansionsocket on the Triton main board. Thishas different connections and thesecan be obtained from the Tritonmanual. It is also necessary to providethe power supply voltages. This canbe done with a small transformer orfrom the existing Triton power supplyrails. In the latter case do not use the-5V rail directly. Instead use the-12V rail and a Zener diode andresistor so as not to overload theexisting circuit.

43

I +5V

26

RESET 35 40

1OR 39

leIN 36

DO 34 37

33 18

32 19

IC131 8255 20

30 21

29 22

28 23

D7 27 24

AO 25

Al 14

15

18

17

A2

f7

+5V +12V Q -5V

24 19 21

9

10

13

14

15

16

17

EPROMSOCKET

23 22 20

18

12

+5V

A7

1014 0

IC3

R24k7

5V

R1Cl 22k100n

11e12

74LS30

i R8MO

DINE1 4

3

IC4i/2 74 L S33

Fig 2. (Above) Main current diagramfor the EPROM programmer.

Fig 3. (Right) Connection table forhooking into Triton.

44

14,8 15 3,16

IC22 74LS123

13

R310k +12V

6-/V\A"--0

01

AMPRI31k0

26V

R4105

R533k

03

R1210k

02

R647R

04

C2 .I.

R718OR

Motherboard EPROM ProgrammerConnector

A20 Reset A5 AO

A21 10R C5 AlAlb 10W A6 A2A22 DINE C6 A3A23 DO A7 A4C23 D1 C7 A5A24 D2 A8 A6C24 D3 C8 A7A25 D4 A1,2, C1,2 OV

C25 D5 A32, C32 +11VA26 D6 A31, C31 -11VC26 D7 A3, C3 +19V

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

PROIECT: Eprom Programmer

When an EPROM is fully erased all of thebits are set to a one so that each locationreads FFH. Programming the EPROM setsselected bits to a zero level. To programthe device, the address has to be set up onthe address pins and the data for thatlocation has to be set up on the data out-put pins. Then a 20 V pulse is appliedto the program pin. Each location has tobe programmed for 100 mS. As there are1024 locations, the programming oper-ation should take about 103 seconds.However life is not as simple as applyingone 100 mS pulse for each location to beprogrammed. The programming pulseduration must be between 0.1 mS and1 mS. In this design a pulse of 1 mS isused. Hence each byte must be program-med 100 times. We are using Triton tocarry out all of the work so this is not acause of concern.

The main work in the programmer isdone by ICI and IC2. IC2 is a TTL mono -stable producing pulses with a 1 mSduration. This pulse could have beengenerated directly on one of the outputport pins using a software timing loop.However, this approach has two disad-vantages. Firstly, if the Triton's clockspeed is altered, the software must bechanged to compensate for this. Secondly,

+19V

-11V

R10100R

1057805

D7BZY88C12V

D8132Y88C5V1

12V

-5V

5V

Fig 4. (Above) PSU circuits for the TRI-TON EPROM card.

BUYLINESTransam Components are producing akit for the Triton EPROM programmerfor £29.50 excluding the case. Ano-ther £2.50 brings you the case as well.Transam Components Ltd,12 Chapel Street,London NW1 5DH.

HOW IT WORKSand more importantly, if an interupt orreset occurred whilst the programmingpulse is in an active state, it will remainactive for longer than the maximumpermissable time, 1 mS and damage theEPROM. The Q and Q outputs are used todrive Q2-4 which generate the 20 V pulseat pin 18 of the EPROM. Q4 is used toprovide an active pull down, since theEPROM sources a few mA of currentwhen the program pulse is low. If a resi-stive pull down were used then the pulsewould not reach OV. R8 and C2 providethe necessary shaping of the pulse. Thecommunication between the Triton andthe EPROM is provided by an 8255. Thisis a device with three programmable eightbit I/O ports. Pin 6 is the CS and this isenabled by IC3 for port addresses FC-FFH. The C5 signal is NANDed withIOR to provide the DINE signal requiredby the motherboard during port readoperations. The 8255 contains fourregisters which are selected by AO and Al.Three of these are the port data registersand the other is a control register. The8255 is used in mode 1. In this mode itprovides three simple I/O ports and portC can be used as two four bit ports. Forcircuit port A is used as the data bus to

10OrnA

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

read data from the EPROM or to senddata to it. Port B is used as an outputport for the lower eight address bits. Thelower half of port C is used as an outputport. The bottom two bits are used forthe remainder of the address bus andthe upper two bits are used to controlthe generation of the program pulse. Theupper half of port C is used as an inputport to monitor the state of the programpulse so that Triton can keep a track ofthe programmer's operations.

While the data and address informa-tion is being set up, po7t C bits 2 and 3are -set to I and 0 respectively. Thisinhibits the monostable and holds the CSof the EPROM active (at OV). When thebusses are ready, bits 2 and 3 of port Care toggled. Now the CS is set to +I2Vto enable programming and the mono -stable is triggered to generate the programpulse. This sequence of events is repeatedfor each program cycle.

No buffering was provided on thebusses as it is felt that the programmer willnot be connected to the bus for much ofthe time and it does not present a load ofmore than one gate on any of the addressor data lines. This has allowed the cost tobe reduced.

R9 D6560R 1N4001

45

ODE 511111CLHow to order: Make cheques etc payable to ETI Book Service. Payment in sterling on y please. Orders

should be sent to: ETI Book Service, PO Box 79, Maidenhead, Berks. All prices include P&P.

-BEGINNERSBeginners Guide to Electronics Squires £3.35Beginners Guide to Transistors Reddihough £3.35Electronics Self Taught Ashe £4.40Beginners Guide to Integrated Circuits Sinclair £3.35Understanding Electronic Circuits Sinclair £4.10Understanding Electronic Components Sinclair £4.10Beginners Guide to Radio King £3.35Beginners Guide to Audio Sinclair £3.35

=COOKBOOKSTV Typewriters Cookbook £7.75CMOS Cookbook £8.20Active Filters £11.30IC Timer Cookbook £7.50IC Op -Amp Cookbook £10.00Video Cookbook £7.00TFL Cookbook £7.55The Basic Cook £4.00 inc. p/pIC Converter Cookbook £9.50

=APPLICATIONSFire and Theft Security Systems B. Weis E2.00How To Build Electronic Kits Capel £2.10110 Electronic Alarm Projects R. M. Marston £3.95110 Semiconductor Projects for the Home Constructor R. M. Marston£3.95110 Integrated Circuit Projects for the Home Constructor R. M.Marston £3.95110 Thyristor Projects Using SCRs R. M. Marston £3.95110 Wave Form Generator Projects R. M. Marston £3.95

-COMPUTING & MICROPROCESSORSWhat is a Microprocessor? 2 cassette tapes plus a 72 -page book£12.00Beginners Guide to Computers and Microprocessors with Projects C.Adams £5.70Basic Computer Games Ahl £5.25Basic for Home Computers A self teaching guide B. Albrecht £4.95Illustrating Basic D. Alcock £2.60Intro to Microprocessors Aspinall £6.50Z-80 Microcomputer Handbook W. Barden £7.75How to Program Microcomputers W. Barden E7.25Introduction to Microcomputers and Microprocessors A. Barns £8.60Microprocessors in Instruments and Control R. J. Bibbero £12.60Basic Basic J. S. Coan £7.80Advanced Basic J. S. Coan £7.30Getting Acquainted with Microprocessors L. Frenzel £7.10Beginners Guide to Microprocessors C. M. Gilmore £4.85Beginners Guide to Home Computers Grossworth £4.50Beginning Basic R. E. Gosling £4.75Microprocessor Programming for Computer Hobbyists N. Graham£7.10Miniprocessors from Calculators to Computers Heiserman £5.00Microcomputers, Microprocessors, Hardware, Software and Appli-cations J. L. Hilburn £17.00Basic Programming J. G. Kemeny £6.55Microprocessor Systems Design E. Klingman £17.00Intro to Microprocessors Leventhal £16.70Microprocessors - Technology. Architecture & Applications D. R.McGlynn £9.00Programming Microprocessors McMurran £5.50Interactive Computing with Basic Monro £3.65Basic with Style P. Nagin £4.25Software Design for Microcomputers Ogdin £7.00Microcomputer Design Ogdin £7.00Microcomputer Base Design Peatman £7.00Hands on Basic with a PET Peckham £8.70Basic -A hands on method Peckham £6.956800 Software Gourmet Guide and Cookbook Scelbi £8.008080 Software Gourmet Guide and Cookbook £8.00The 8080A Bugbook: Microcomputer Interfacing & ProgrammingP. H. Rony £8.20

8080/8085 Software Design Titus £7.6057 Practical Programs & Games in Basic Tracton £6.60

Microcomputer Primer M. Waite £6.50Your Own Compqer Waite £1.50

Microprocessor/Microprogramming Handbook Ward E6.20

LOGICLogic Design Projects Using Standard ICs J. Wakerly £5.10Practical Digital Design Using ICs J. Greenfield £12.70Designing With TTL Integrated Circuits Texas Instruments £9.05How To Use IC Circuit Logic Elements J. Streater £3.65110 COSMOS Digital IC Projects for the Home ConstructorR. M. Marston £3.95Understanding CMOS Integrated Circuits R. Melen £4.00Digital Electronic Circuits and Systems R. M. Morris £3.50MOS Digital ICs G. Flynn £5.10

=TEST INSTRUMENTSThe Oscilloscope In Use Sinclair £3.10Working with the Oscilloscope A. Saunders £4.10Servicing with the Oscilloscope A. King £6.50Radio Television and Audio Test Instruments King £6.80

= OP -AMPSApplications of Operational Amplifiers Graeme (Burr Brown )£8.30110 Operational Amplifier Projects for the Home Constructor R. M.Marston £3.95Designing With Operational Amplifiers Burr Brown £16.65Operational Amplifiers Design and Applications G. Tobery (Burr Brown)£7.40Op -Amp Circuit Design & Applications J. Carr £4.00

=COMMUNICATIONSCommunication Systems Intro To Signals & Noise B. Carlson £7.50Digital Signal Processing Theory & Applications L. R. Rabiner £23.80Electronic Communication Systems G. Kennedy £8.50Frequency Synthesis. Theory & Design Mannassewitsch E23.40Principles of Communication Systems H. Taub £8.10

=THEORYIntroduction to Digital Filtering Bogner £10.20Transistor Circuit Design Texas Instruments £9.35Modern Electronic Maths Clifford £6.70Foundations of Wireless Electronics M. G. Scroggie £5.00

=REFERENCEElectronic Engineers Reference Book (Ed. 4) L. W. Turner £34.00Electronic Components M. A. Colwell £2.60Electronic Diagrams M A. Colwell £2.60International Transistor Selector T. D. Towers New update £8.70International FET Selector T. D. Towers £4.35International Op -Amp Linear IC Selector Towers £7.50Radio Valve and Semiconductor Data A. M. Bell E3.45Radio, TV and Audio Technical Reference Amos £24.85

=MISCELLANEOUSElectronic Fault Diagnosis Sinclair £3.20Integrated Electronics J. Milman £7.90Practical Solid State DC Supplies T. D. Towers £6.20Practical Triac/SCR Projects for the Experimenter RPrinted Circuit Assembly Hughes & Colwell £2.60

Fox £2.25

Fallen behind recent advances?Just starting out?Need a decent reference book?Ell Book Service provides an easyway of getting your handson the right title.

46 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1 980

co°910A-svtos LB ELECTRONICS s..0,00pS

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SY' UXBRIDGE 55399

PCB OFFERS(1A) Video Store PCB 115mm x94mm containing 10x TMS 3409(4 x 80 Dyn. Shift Reg.) + Dis-metes, etc. £2 each, p & p 30p(limited stocks).(1B) PCB 280 x 210mm con-taining TR 1602-A (DART), XTAL19.2 KHZ, 8 DIL Switch, + 64 74 -series ICs + LM 301 + Discretes.FANTASTIC VALUE E3.60 + 50pp & p (limited stocks).(1C) PCB 215mm x 290mm: 12xTMS 3112) (or sim,), Hex 32 -bitShift Reg. + 39 ICs E2 + 50pp & p limited stocks).

MPU CORNER2112 (200ns) £3. 2114 (450ns)£4.50-1702 £2.50; 2708 (400ns)E7.252716 (Single Rail) £28.50.74125 4 for CI + p & p 25pMK 1002P (dual 128 bit Shift Reg)35p.LM711CH (Voltage Comparator)30p.MM5240 Character Generator +Data 2560 Bit (64 x 8 x 5) £3.50,p&p 25p.

(All Full Spec)

D TYPE CONNECTORS9 Way: plg 40p; skt 40p.15 Way: pig 40p; skt 50p.25 Way: pig £1.00;. skt £1.00(RS232).37 Way: plg £1.40; skt £1.40.50 Way: skt (wirewrap) £1.55.50 Way: skt £1.45.

COVERS37 Way: 80o.25 Way. 65p .Plastic) p & p 25p

DISPLAYSMAN 72 7 seg CC £1.25, p/p25p.,Burroughs Panaplex 9 Dig. + sktand bezel £1.00, p/p 25p.LED 3 Digit DIL 55p, p/p 25p.LED 4 Digit DIL HP 5082 CC0.11" (RED), E1.50, p/p 25p.

SUPERSAVERRibbon Cable Headers 16 DILJermyn, gold plated, with cover,45p, p&p 25p.

SUPERSAVER 2Tantalum Capacitors 25 volt, 4.7uF, 14 for £1.00, p & p 25p.

SUPERSAVER 3Mercury Batteries 1.35v 1AH. Die.15mm. height 18mm, 35p, p & p25p.

SUPERSAVER 4HYBRID SYSTEMS DAC 371-8 8Bit, Oil packaged, ideal MPU userswith data, £2.95, p & p 25p.

SUPERSAVER 5LM 323K Voltage Regulator, 5 volt3A. £4.50, p & p 25p.

SUPERSAVER 8RS 338-383 Miniature DecadeThumbwheel Switch, £1.85, p & p25p.

SUPERSAVER 7SN74114 Dual 4 Bit latch, 75p,p & p 25pSN74181 Arithmetic Logic Unit,80, p & p 25p.SN74194 4 Bit Shift Register,50p, p & p 25p.SN74198 8 Bit Shift Register,715p,p&p 25p.

SUPERSAVER 8BC108b Sp each or 100 forE7.00, p & p 25p.

SUPERSAVER 94 Digit 7 segment LED BubbleDisplay, NSA 1540A Ex equip-ment, 5 for £1. p & p 25p.

SUPERSAVER 109 way male/female connector,ELCO 8129, 0.1 inch pitch, gold-plated PCB mounting, ideal forbussing two PCBs together.Superb value, 35p, p & p 25p.

SUPERSAVER 11500 ohm multiturn trimpots PCBmounting, 30p, p & p 25p.

SUPERSAVER 12TMS 3128NC Static shift register,£1.50, p &p 25p.

SUPERSAVER 13PL529 (UHF) Elbow Connectors,50p each, p & p 25p.

SUPERSAVER 141 S423 Stud mounting rectifiers,400v 10A, giveaway pride, 10 for£2, p&p 25p.

SUPERSAVER 1520K Painton multiturn trimpots,PCB mounting, per box of 14E2.50, p &p 25p.

LEDsTIL209, red, 10p; 0.2". red, 12p;0.2". green, 28p; 0.2", yellow,

RL54 red Axial lead, 15p.P & p on all above 25p.

VERNITRON Ceramic filters, typeFM4, 10.7 MHz, 45p, p & p 25p.

TRANSISTORS, 80236 40p,BC183L 10p, BF195 10p, SGS2N3055 30p; p & p on all 25p.TBA 810S, with data, 85p; 4 -wayOIL switches, 75p; MC1303 DualStereo preamp with data, E1.215;7" Nylon cable ties, 100 for£1.50. All p & p 25p.

NEW SN78477 (Yes, back instock). Sound Generator IC (Train,plane, explosion, laser gun, etc.),with data, £3.25, p & p 25p.

PCB 'KEYBOARD 6 5mm x82mm, 18 Key Clickers less Key -tops, ideal Hexadecimal use, 35p,p & p 25p

PACKAGED 10 -WAY REEDrelay, 12v coil, terrific value, 50p,p&p 25p.

IR12T2OT BRIDGE RECTIFIER,12A 200v, single or 3 -phase, 95p,p & p 25p.

NEW PERANCEA CASES:These superb cases now stocked inthe DIN range incorporating thefollowing features, Matt black fin-ished bezels snap fitting onto casefront, firmly retaining either of thefront panes provided, onealuminium, one RED anti -reflective. Each case has two sets ofguides with rear panel slots for PCBmounting.

Types available:DIN 1458 £3.75DIN 2368 £3.00DIN 1466 E3.80

P & p 25p. S.A.E. for leaflet

WE STOCK PETS

8K version £599. S.A.E. for PET/SORCERER software lists at dis-count pricesWe can also offer a 48 -hour repairservice for out of warranty PETS.Telephone for details.

IC HOLDERS8 Dil 12p. 14 Dil 15p.

16 Dil 17p. 18 Dil 32p.

24 Oil 48p. 28 Dil 85p.

All p & p 25p.

WE STOCK a vast range of TTL,CMOS, some 74LS, MINIATURETOGGLES. etc.PSUs. We have a large stock ofpower supplies at very realisticprices (callers).

RELAYSITT 700 ohm Single polechangeover, 45p; BANOR reset -table double pole changeover. £1;both p & p 25p.

CIRCUIT BREAKERS450v AC 65v DC 0.5A 50p: ditto7A SOp: p & p 25pALLEN KEYS, 7/ 16" 5p: 12 for50p; p & p 20p.

FOR CALLERS ONLY(or carriage at cost)

1 ONLY Viatron 21 Data manage-ment system comprising proces-sor, video monitor, cassette tapedrive, keyboard, modem interface.4 lines of 80 characters per tape filrecord. Autosearch /list facilities.To clear £185 + VAT (withmanual).

1 ONLY MOORE REED miniponDT106 portable data terminal.110 baud keyboard /printer withinternal modem and ACOUSTICCOUPLER for connection totelephone. Standard ASCII code,Full / Half duplex, 80 char. per line.£300 + VAT.1 ONLY GEC 9000 Visual DisplayUnit Green phosphor, cursivecharacter gen. 600/ 1200 baudasynchronous serial. £125.1 ONLY CALCOMP 142 DiscDrive with manual. Fully tested onExorciser. £185 + VAT.

Terms: Cash with order (officialtraders welcomed from colleges,etc.). All enquiries s.a.e. please.All prices inclusive of VAT, unlessotherwise stated. Postage asshown per item.

LB ELECTRONICS11 HERCIES ROAD

HILLINGDON, MIDDLESEXUB10 9LS, ENGLAND

New retail premises now openMon., Thur., Fri. and Sat., 9.30-6.00. We are situated just off theA40.

UXBRIDGE553993

All components fullspec

STRATHAND SECURITYWE HAVE EXPANDED TO NEW PREMISES AT 32 ST.ANDREW'S SQUARE, GLASGOW, WHERE WE CANNOW OFFER AN EVEN BETTER SERVICE, WITH A

LARGER RANGE OF PRODUCTS AT BETTER PRICES

Our Telephone Number and Telex No. remainunchanged

Solfan Microwave - 1 5M Range - neat and unobtrusive -ideal for home and office. Requires 12V DC at 130 MA.Normally closed contacts open under attack condition. Walktest lamp built in.This month's price inclusive of V.A.T. and P. and P £74.75Flush Reed Switch and Magnet £1.00Surface Reed Switch and Magnet £1.00Pressure Pad, large £2.50Pressure Pad, stair size £1.75Bell 12V DC 6 -inch Heavy Duty, very loud £11.50Horn Sounder 110 DBA 12V DC 0.6A . . . £22.00All prices include V.A.T. at 1 5%, postage and packing.

Many other items too numerous to detail. Price List free withs.a.e. Catalogue, giving wiring details, etc., only £.1 .00refunded on orders over £10.00.

THIS MONTH'S BARGAIN OFFERBell Cover - plastic coated steel - normally £8.50 - thismonth ONLY £6.50

Special discounts for orders over £250.00

All goods are held in stock and are despatched normally within24 hours. For prompt service Phone Nancy on 041-552 6731.

Callers Welcome

STRATHAND alk==.432 St. Andrew's Square, Glasgow, G1 5PL

Tel: 041-552 6731 or 2Telex: 777268 (24 hours' service)

MasterElectronics

The practical wayNo maths needed -

No dull theory-Step by step vve take you through all the fundamentals ofelectronics and show you how easily the subject can bemastered.1) BUILD AN OSCILLOSCOPE2) READ, DRAW AND UNDERSTAND CIRCUIT DIAGRAMS3) CARRY OUT OVER 40 EXPERIMENTS ON BASIC

ELECTRONIC CIRCUITS AND SEE HOW THEY WORK.

We provide practical tuition for:- 3) Digital Electronics1) Radio amateurs licence. 4) Computer Technology 2) City and Guilds certificates.E 5) Test instrument kits CI

Mark your interest(s) with an x in box provided.British National Radio & Electronics School,NAME P.O. Box 156, Jersey, Channel Islands

ADDRESS FT01

IL(block caps please)j

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 47

VT10Same daydespatch

VT208mm thick

MUSICALALARM

Chrono-playsmelody on alarms6 digit II functionscountdown alarm,Dual time zone,1/100th secchrono, 2 pieces/s bracelet

£24.95inc. VAT P&P

aond,t1)LCDSNOOZEALARM24 -hr. alarmHours, Mins.,Secs., date,month, back -light,auto. calendar.Adjustablestainless steelbracelet,

- 12 -monthguarantee.

ONLY£10.95(inc. VAT. P&P)

BELTIMECHRONOGRAPH9 FunctionsHours, mins,secs, day, date,month,interchangefeature,automaticcalendar,backlight, nettime/lap time.Stainless steelbracelet, 8mmthick£10.95(inc. VAT P&P)

VT07Sone dory despatch

1141 LADY'S5 FUNCTIONWATCH

Hours, minutes, secsday, date, month,backlight, gilt or silver

£10.95;inc VAT P&P)

READY BUILT RADOFIN TELETEXNO INTERNAL TV CONNECTIONS!

Double height character facility Resolution doubled for easier viewing True PAL colour for 'Able! reproduction Meets latest broadcast specifications by BBC and IBA Push button channel change Unnecessary to remove the unit to watch normal Pd

programmes Silent keys on remote controller - distinctive tone tells

you a new entry is being made Gold plated circuit board for long life and high reliability Stylish cabinet to suit all decors

Dimensions:Main Cabinet - 400mm length. 205mm depth. 105mm height.Remote controller - I 12mm depth. 53mm width. 20mm height

Input voltage: 240 volts AC 50Hz.

Get more out ofyour television

ONLY £212.75 inc. VAT

ATARI VCS System- Most popular top rangemicro -video game

Current cartridges - Air Sea Battle (27),Space War (1 7). Outlaw (16). VideoOlympics (50). Breakout )12). Basketball(2) Surround (14). Blackjack (7) BasicMaths (8). Codebreaker (20). Hunt & Score(8) Miniature Golf k2) Skydiver 151, StreetRacer (27), Chess (8), Levels Backgammon(8) Brain Games, Bowling.

VCS Unit - £159.95 inc.Cartridges mostly - £14.95 inc.CHESS (8 levels) - £45.00 inc.BACKGAMMON - £34.50 inc.SUPERMAN - £23.25 inc.INDY 500 - £34.50 inc.

details on request.Same day despatch.

TELENG TELEVISION COMPUTER SYSTEM- low cost micro -video game - British made

Details onrequest

Comescompletewith Sportsworld

Sportsworld, Combat, Horse Racing,Maze Maths Two, Far in Raw,

Mastermind, Air -Sea Battle,Boxing, Black Jack,Sporting Shotgun,

Motor Racing,Maths One Circus

Console - £89.95 inc.Cartridges - £12.95 inc.

PHILIPS G7000 - HOME VIDEO COMPUTER GAME

-a new dimension to video gam11 exciting VIDEOPACSPAC 1 - Motor Race,Spin -out, Cryptogram, PAC2 - Paris, Space Rendez-vous, Logic, PAC 3 -American Football, PAC 4- Air -Sea and Tank BattlePAC 5 - Blackjack, PAC 6- Ten Pin Bowling, Basket-ball. PAC 7 - Maths, Echo.PAC 8 - Baseball, PAC 9 -Computer (Assembler andMachine code). PAC 10 -Golf . PAC 11 - SpaceConflict.

G7000 - £149.95 inc.VIDEOPACSmost each - £12.95 inc.

es fulldetailson request

Samedaydespatch

G7000 includescontrols, adaptor,VIDEOPAC 1

50 HZSUPERBOARD II

£216.20 inc. VAT

CASE - £29.95 inc.4k RAM - £40.25 inc.(8 x 2114)COLOUR - £59 inc.BUILTADD ON

SOLAR LCD ALARMCHRONO

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7

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Same day despatchSame as ETI spec.

VT06

SOLARLCD ALARMCHRONOGRAPH24 -hr alarm withon/off indication1 / 10 secondchronographmeasuring net,lap and first andsecond placetimes.Dual time zonefacility.Night light.

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VT12

1 -month guarantee. 15% VAT included. Cheques or P.O.s or telephone Card No. toAllow 7 days delivery unless specified

VIDEOTIME PRODUCTS, 56 QUEENS ROADBASINGSTOKE, HANTS RG21 1 REA. Tel: (0256) 56417 or 26620 TLX: 858747

FACTORY AGENTS \A ANTED MONEY BACK GUARANTEE OFFERS SUBJECT TO AVAILABILITY. TRADE ENQUIRIES WELCOME

48 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

FEATURE

ELECTRONICS INTHE STUDIOTim Orr - the man of a thousand circuits - takes us on a touraround the cables of a recording studio.

the last decade has seen an enormous growth in thequantity of electronic hardware that is used inrecording studios. The list of equipment now avail-

able includes 24 track tape recorders, 48 channel mixers,computer assisted mixing, spectrum analysers and a wholehost of electronics effects gadgetry. These high technologysolutions have made the job of producing recordings mucheasier but the tasks now demanded of the studio engineerhave increased.

It is sobering to remember that the early Beatles'albums were produced in one day on a four track recorder.No matter how hard we try, technology cannot producemusic; it can only provide the 'tools for the job'. In facttechnology has in some ways, had a detrimental effect onmusic production with the idea that if you have sufficientrecording tracks to spare you can get it right on the final mixdown.

A Typical StudioA typical recording studio is split up into two working areas:the performance area and the control room - containing allthe electronics and associated hardware. The performancearea is soundproofed to provide about 80dB's of acousticisolation from the outside world. The walls, floor and ceilingare all made from very dense materials to absorb sound.The room itself is usually acoustically flat, having little orno reverberance or resonances. Often there are mobileacoustic baffles, (vertical sheets of board), that can bepositioned in between musicians to provide some amountof acoustic isolation between them. These are often usedfor drums. There is a studio talk back system so that thecontrol room can talk to the musicians or play themrecordings. The microphones plug into floor or wall socketsand are connected directly to microphone amplifiers in thecontrol room. A large double glass window separates thetwo halves of the studio.

The control room houses all the electronic equipmentneeded to produce the recording. All signals pass through amulti -channel mixer which is used to provide control overthe volume, tone and any special treatments that need to beperformed on a particular sound. The usual approach forproducing a recording is to build it up track by track so thatthe music is broken down into its basic ingredients, (i.e.bass line, melody, vocals, strings, drums), which are stored

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

on a multi -track tape. This can then be mixed down by theproducer to get the required overall balance. The mixer canbe used to fade in and out various tracks and to provideequalisation.

Graphic EqualiserA Graphic equaliser is a very flexible tone control operatingover the audio spectrum. This spectrum is broken up intosegments, each being controlled by a slider which canprovide up to 1 2dB of cut or lift. Thus it is possible to drawout, using the sliders, an overall frequency response which

49

will be imposed upon the audio signal. The position of thesliders graphically display the frequency response curve.

STUb10TALI( BACA

DOUBLE GL ASS

"VVIVD' "

JACNFIELD

ELECTRONICEFFECTS

UNITS

MOBILE ACOUSTIC BAFFLES

vARiOu OPHONES DRUM KIT

/ MIXER

TAPE DECKS RECORD12 INCH TAPE DECK

DOOR

Fig 1. A typical studio layout.

SOUNDPROOFED

PERFORMANCEAREA

--- SOUNDPROOF-- DOORS

a- STUDIOMONITORS

ECORDING LAMP

Compressor/ExpanderTwo problems that are ever present are noise and over-loading. To prevent overloading of equipment you cansimply operate at a low signal level but this results in a poorsignal to noise ratio. To obtain a good signal to noise ratioyou should operate at a higher signal level but this willprobably result in overloading and distortion!

An enormous amount of programme material is listenedto on radio sets which typically have a reception signal tonoise ratio of between 40 to 55dB and which are used innoisy environments. Thus the programme sound level mustbe very tightly controlled. If the signal level is too large thenthe radio transmitter will be over modulated causing grossdistortion; if it is too small the signal will be lost in noise.Generally broadcasting companies try to limit their pro-gramme material to a range of about 16dB. Also whenrecords are cut the dynamic range must be tightly control-led as a disc can only provide 60dB (usually less) signal tonoise ratio.

SLIDERKNOBS

vol

.i1'Iis20HZ

441OHZ

Fig 2. A graphic equaliser and response.

12dB

12dB

50

LIFT

FLAT

CUT

20HZ 20K HZFREQUENCY RESPONSE

If the signal level is too large the cutting will breakthrough into its neighbouring grooves. Even if it doesn'tactually break through it can cause a material deformationof the master disc that produces a noticeable pre and postecho. When a disc is cut the general brief for the disc cutteris to get as large a cut as is possible without producing anycross talk and to do this the recorded material should nothave any nasty signal peaks.

OUTPUT

dBm.10

10

-20

-30

-40

-50

-60

-60 -50 \\-40 -30 -20

2 T01 EXPANSION NOISEGATE

-50dB THRESHOLD

2 -1 COMPRESSION

LIMITING-10dB THRESHOLD

-10 0 0dBm

INPUT

COMPRESSOR/EXPANDER

Fig 3. Compander limits and response

Level ControlThere is a large selection of equipment available to controlthe signal level of programme material and these are knownas compressors, limiters and expanders.

A typical device will have controls that set the thresholdpoints, the compression and expansion ratios and theresponse times.

A limiter is a device that prevents the output signal fromrising above a set threshold. As the input signal attempts todo this, a voltage controlled attenuator turns the signallevel down. The effects of limiting are rather harsh and areusually only used to prevent overloading in some other piceof equipment. Compression is also used to reduce over-loading but it is more subtle.

If say, a two to one ratio has been selected then as thesignal level exceeds the threshold the output will increaseby only 3dB for every 6dB increase of the input. By usingboth a compressor and a limiter at once it is possible to runat 6dB below the maximum operating signal level for asystem and still handle signal excursions of a further 1 8dBwithout noticeable distortion.

When the input signal is very noisy as for example, atelephone news report, or an old film sound track, anexpander can be used to clean up the sound quality. Anexpander is a device that attenuates the signal when it fallsbelow a pre-set threshold. A two to one expansion ratioreduces the output signal by 1 2dB when the input signalfalls by 6dB. A more dramatic effect is a noise gate whichhas an expansion ratio of about 20:1 or even more.

The speed with which compression or expansion occursis controlled with switchable attack and decay times. Thisallows the user to select the best time constants for the jobin hand.

Another but more specialised type of signal level con-troller is the voice over or ducking unit. This enables a DJ toautomatically fade the music down to a preset level everytime he speaks. When he stops the music rises back to its

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

FEATURE: Electronics In The Studio

original level. The attack and decay times for the duckingare adjustable.

Above: an Audio Design compander.

Above: an Audio Design voice over unit.

Noise ReductionThe signal to noise ratio of a professional tape recorder isabout 60dB, which is mainly due to the limitations of thetape. This is not good enough for professional recordings,particularly when many sound tracks have to be mixedtogether. What is needed is a system for improving theperceived signal to noise ratio. An expander does this but itdistorts the natural dynamics of the signal in that the signaldies away abruptly after it falls below the threshold. Asystem that overcomes this problem and which is widelyused in studios is the Dolby A system. The signal to berecorded is pre-processed with a low level compression.That is, low level signals are selectively made larger whilstthe high level signals are unaffected. The signal is thenrecorded on tape and in doing so tape noise is added.

When the tape is replayed a low level of expansionexactly complimentary to the compression previouslymentioned is performed. This reduces the effect of the tapenoise in the periods of silence but does not corrupt thesignal dynamics because of the complimentary compres-sion and expansion.

Also, the process is performed in four independentfrequency bands so that "breathing" effects are reduced.The advantage of using low level compansion is that thedistortion caused by it appears only on low level signals andis thus not very noticeable. Also low level compressionmakes very little difference to the maximum signal level. Animprovement of 10dB is obtainable using the Dolby Asystem.

Echo And A D TElectronic delay lines are often used to produce a widerange of effects such as flanging, chorus, automatic double

tracking and echoes. There are two methods of implemen-ting time delays, one is with bucket brigade delay lineswhich are useful for short delay (1 to 40 mS.) low costunits, and the second is with digital delay lines. These arebest used for 10 mS to 1 S. delay times in high qualityunits, (usually costing £500 upwards).

INPUT

Fig 4. (Above) Block diagram of an echo unit.

(Below) The resulting outputs.

INK, 4 vv- Ann. DUE-DELAYING ECHOS

011T,JT

Automatic double tracking (ADT) simulates the sound ofa second instrument playing along with the original. A timedelay of 10 to 40 mS is generally used and the delayedvoice is mixed in with the original so you effectively get twomusicians or singers for the price of one. To improve thenaturalness of ADT the time delay is slowly modulatedthus generating very slight timing errors. Another effectsimilar to ADT is 'chorus' where one or more delays linesare used with a slightly shorterdelay time, (5 to 10 mS) thuscreating a richer, more complex sound structure.

Echo is often obtained using a digital delay line. Theinput sound is converted into a binary word with an ADC,stored in a large RAM and then converted back sometimelater into an analogue voltage using a DAC. The memorysize is often very large. Take, for example, an echo unitwhich has to have a 60 dB dynamic range, a 10 kHzbandwidth and an echo length of 1 second. The systemmust be 10 bits wide and have a clock speed of 25 kHz,thus the number of bits of memory needed is 25K x 10 =250,000 bits, which would be 250 1K RAMs costingabout £1 each!

FlangingFlanging is a popular effect that is implemented using acomb filter. The comb filter response is produced with ashort delay line, (1 to 10 mS) where the original anddelayed signal are mixed together. This generates afrequency response which has a series of linearly spacednotches, the spacing of these being inversely proportional

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 51

DEPTH

TIME DELAY MODULATION

INPUT

SPEED

OUTPUT

Fig 5. (Above): Flanging and how it is obtained. Below is shown thefrequency response of a comb filter.

OUTPUTINPUT

EFFECT OFREGENERATION

LINEARFREQUENCY

to the delay time. By applying feedback around the delayline, the comb becomes more peaky and so provides morecolouration of the sound. The delay time is slowlymodulated and this produces an interesting mobile colou-ration of the sound. Flanging and phasing are oftenconfused as they are both produced by comb filtering.Flanging uses a time delay and generally has lots ofnotches, sometimes as many as 50, whereas phasing usesphase delay and usually has only 2 or 3 notches.

INPUT WAVEFOR

OUTPUT SHIFTED DOWIONE OCTAVE. READIN(SPEED IS ONE HALF OFWRITING SPEED. NOTETHAT C AND D HAVEBEEN DISCARDED

OUTPUT IS SHIFTED UPONE OCTAVE. READINGSPEED IS TWICE OFWRITING SPEED. NOTETHAT ABCD HAVE TOBE REPEATED TO FILL INTHE TIME GAP

UIDIO

ANALOGUETO DIGITALCONVERTER

RANDOMACCESSMEMORY

DIGITAL TOANALOGUECONVERTER

AUDIOADC RAM DACNPUTDATA DATA OUTPUT

1

FIXED WRITING SPEED

A B E

DISCONTINUITY

A B C+ D A B C .1, 12

ktlififV17

..1..

f\i'krifDISCONTINUITY DISCONTINUITY

Fig 7. Pitch shifting in practise.

the melody should be the same, but the pitch transposed.To satisfy these conditions the memory size should berelatively small (20 to 40 mS). Take the case of the uptransposition of one octave. If the reading speed is twice asfast as the writing speed then each segment of sound willhave to be played twice, otherwise gaps would appear.However, when the transposition is down by one octave,

SPEECHINPUT

ANALYSING 2 QUADRANTFILTER BANK MULTIPLIERS

SYNTHESIZINGFILTER BANK

L OUTPUT

- EXCITATION INPUT

BROADSPECTRUMOBTAINEDBY ANALYSINGSPEECH

EFFECTIVELY THE VOCAL TRACTFREQUENCY RESPONSE

VARIABLE READING SPEEDCLOCK

Fig 6. Digital pitch shifting techniques.

Pitch Shiftingit is now possible to transport the pitch of an instrumentusing a pitch shifting device. The shifting is not perfect, butit is good enough to produce useable harmonies. Theoperation is as follows. The input signal is converted into abinary code and written into memory. At the same time thememory is read, but at a different speed and this data isconverted into the audio output using a DAC. If, say, thereading speed is twice that of the writing speed then theoutput will be transposed up an octave in pitch. There aremany problems to be overcome. First, the output must notbe significantly delayed. Second, the time varying infor-mation of the output must rapidly track the input, that is,

TYPICALLINESPECTRUMOFEXCITATION

VOCODEROUTPUTSPECTRUM

11;11

; 1111

!!!!!

FREQUENCY

11111111111111 FREQUENCY

FREQUENCY

Fig 8. A representation of the Vocoder principle and waveformsexpected.

UITY

52 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

FEATURE: Electronics In The Studio

then half of the information cannot be read in time and sohas to be discarded. Pitch shifting units are usuallycontinuously variable over the range of plus or minus oneoctave.

VocodersA vocoder is a device for producing a cross product of twosounds. If the two sounds are speech and an electric organ,then the resultant sound output is a talking organ. Whenwe speak we produce a buzz in our vocal chords that isacoustically filtered by our vocal tract. The buzz becomesarticulate, it speaks. The vocoder uses a filter bank toanalyse the speech so it can determine the time varyingfrequency response of the vocal tract. It then synthesises amodel of this frequency response using a second filter bankplus some multipliers. The excitation signal (the electricorgan), is then filtered by this model and so becomesarticulate. The vocoder output has the melody and har-nonics of the excitation signal, but the time varying broadspectrum (the articulation) of the speech.

Above: a typical portable mixing unit. This one is produced byStudiomaster and will mix sixteen channels into eight.

MixersThere is a wide variety of mixers on the market today,ranging in price from £20 to £20,000. Basically, the moreyou pay, the better the product. A mixer is composed ofinput and output channels; for example a 16 into 8 devicehas 16 inputs and 8 outputs. A typical input channel hasthe following controls. An input gain switch so that lowlevel signals from microphone sources up to high levelstudio signals can be accomodated. An overload lamp or aVU or PPM is usually provided so that the signal level maybe monitored. Next is a tone control section, perhapsconsisting of Bass, Middle, Treble and sometimes a fewparametric control functions. Many mixers also have anecho send control so that reverb may be added to thatchannel. A foldback control is often included. This is aninternal mixing system so that a few tracks can be groupedtogether and fed back via head phones to the musicians.

A pan control enables that channel to be sent to either ofthe left and right output groups. Routing switches are usedto connect a particular channel to any output group. A levelslider, always at the bottom of the channel allows theoperator to fade in and out the sound from that channel?

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

Above: the EMS Vocoder 2000, a very popular unit and one whichthe author helped to design in his days at EMS.

Fig 9. The frequency response of a chorus unti which employs threeflanging units without regeneration. The scope picture wasobtained using a swept sine wave oscillator set to run the audioband.

You might get a nasty surprise! You won't if you have got aprefade listen switch. This connects the signal at the top ofthe slider to some monitoring device, so that the operatorcan have a sneak listen to a channel before fading it up andperhaps ruining the output.

To produce a controlled mix down the operator will needto be very skilled and possibly he will need ten pairs ofhands!

Computer MixdownTo ease the burden of mixing down 32 channels, NeveElectronics has produced the NECAM computer assistedmixdown system. The computer can remember severalmixdowns and replay them. The sliders are servo drivenand so they provide a visual indication of what is actuallyhappening. The slider knobs have promity switches so thatthe operator merely has to touch them to regain control.

This system is however, 'slightly expensive'! ET1

53

ETIPRINTS are a fast new aid for pro-ducing high quality printed circuitboards. Each ETIPRINTS sheet con-tains a set of etch resistant rub downtransfers of the printed circuit boarddesigns for several of our projects.

ETIPRINTS are made from our originalartwork ensuring a neat and accurateboard. We thought ETIPRINTS weresuch a good idea that we havepatented the system (patent numbers1445171 and 1445172).

PARTS LISTShown below is the listing forthe last year's ETIPRINTS.

013 Amplifier ModuleAmplifier PSUEqualiserEqualiser PSU

014 Skeet GameSweep OscillatorBurglar AlarmGSR Monitor

015 UFO DetectorTorch Finder (twice)Etiwet (twice)

016 Stac TimerXhatch GenWheel of Fortune

017 Complex Sound GenTele Bell ExtenderPower Bulge

018 RF Power MeterProximity SwitchAudio Oscillator (2)

019 Car Alarm (2)Wine Temp (2)Curve Tracer

BookSix

ProjectBook

Six

July 78July 78Aug 78

Sept 78

Oct 78

Oct 78Oct 78Nov 78

Dec 78Dec 78Dec 78

020

021

022

023

Earlier sheets are available,ring Tim Salmon for details.

Digital TachoModuleDigital Dial

Tape Slide SynchTape Noise LimiterLight Tacho

Logic TriggerPower MeterHeadlight Delay (x2)

Click EliminatorGuitar Effects Unit(2 boards)

023A Wind Speed Indicator

024A Ambush (Boards 2 & 3)Car Immobiliser

024B Ambush (Board 1)Headphone AmplifierDouble Die

025 MetronomeMains SeekerTriton 8K Eprom Card

026 Motor Speed Controller(2 Boards For Controller)Battery Indicator

Jan /9Jan 79Jan 79

027 CCD PhaserRev. Monitor

Feb 79 028 Race Track, Spirit LevelEgg Timer, BongosBench Supply, Oscillator

ProjectBookSeven

ProjectBookSeven

Mar 79029 Bass Enhancer Project

Digital Freq. Meter (4 boards) BookSeven

April 79

April 79May 79

May 79

June 79

July 79

030 ETIWET, Continuity TesterMetal Locater, Light DimmerUltrasonic Switch (2 boards)

031 Tone ControlHouse Alarm (2 boards)Torch Finder

ProjectBookSeven

ProjectBookSeven

LED Audio Display (2 boards) Aug 79(underside pattern)

033 LED Audio Display (2 boards) Aug 79(topside pattern)Bench AmpNICD Charger

HOW IT WORKSLay down the ET/PR/NT andrub over with a soft penciluntil the pattern istransferred to the board. Peeloff the backing sheetcarefully making sure thatthe resist has transferred. Ifyou've been a bit carelessthere's even a 'repair kit' onthe sheet to correct anybreaks!

BUY LINESORDER TODAY

Send a cheque or P 0 (payable to ETI Magazine) to

ETI PRINT, ETI MAGAZINE145 Charing Cross Road, London WC2H OEE

8054

pINC P & PELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

(-10 (.1 04).20 x 20 WATT STEREO AMPLIFIERViscount IV unit in leak simulate cabinet Silver finish rotary controls andpushbuttons with matching lama, red mains indicator and stern jack socketFunctions switch for mic magnetic and crystal pickups. tape tuner and auxiliaryRear panel cairns fuse holder, DIN speaker and input sockets 20 x 20 wartsRMS 40 x 40 watts peak for use with 8 to 15 ohm speakers.

Sae 14kk" x 3" x 10" approx NEW feature -until row f j I yuincludes a bush in four channel stereo sound facility f 3 00 p&p

30x30 WAIT AMPLIFIERIN KIT FORMFor the experienced constructor cornplete in every detail same facilitiesas Viscount IV but with 30x30 output6060 watts peak For use with 4 tolSohms speakers

R840

f31.50 f300

SPECIAL OFFER30 x 30 WATT AMPLIFIER KITwith BSR P200 belt drivedeck and ShureM75 cartridge.

f57.00+ p&p 16.00

EMI SPEAKER BARGAINStereo pair 350 kit System consists of13" x 8" approx woofer with rolledsurround. 21/2" wpm, Audas tweeter,crossont components and circuitdiagram. Freouency response 20 Kato 20 KHz Rower handling 15 waits RMS20 wens max8 ohm impedance

£18.25Per stereo pair

(3.65 p&p

BSR P200Belt drive chassis turntable unit f25.50semi -automatic. cueing device p&p f 2 60

A 0.0 01.M 30 Mk Ill Magnenc Cartridgeto suit f7.95

GARRARD DECKMODEL CC 10ARecord changer with cueing devicetilted with stereo ceramic cartridgeready to fit pito your own plinth

f8.15 p&p f2 05 Size 12" x 8'/1

4

Manual single play

record desk wily auto

return and cueing lever lined with stereoceramic c &nudge 2 speeds with 45 r p

spindle adaptor ideally coded for homeOr disco use E P&POUR PRICE £11.23 f2 75

BSR

UNIT AUDIO STAND.--Can be used with TV too Finish

in chrome with decorative woodspacer fitted with 4 KenrickMini Meteor castors

f3.95 62.25 p&p

24" x 121/2" x 111/2"approx.

BARGAIN FORPERSONALSHOPPERS ONLY

.414-112 Kt. Altone UA4ICI Stereo System

Features 8 watt total output. Full size BSR manual turntablewith cueing and auto return Socket for tape in and out andstereo headphones

complete with speakers

Micro Cassette RecorderPocket size -home or office use orwhen travelling

Battery operated fluorescentcamping lamp.Runs off 8 U2 batteries

f35.75

f14.25

14.80

MullardAUDIO MODULES INBARGAIN PACKSCURRENT CATALOGUE

PRICE Ensue '1AT OVER MK' IA '

PER PACK rj.000°.\\\SEE OUR PRICES

1PACK I 2 a 11,1173 lOw RMS output power audioamp modules, e 1 LP1182 /2 Stereo pre amp forceramic and auxiliary input

OUR PRICE

pop (I 00 f5.00

2 PACK 2 2 101173 lOw RMS output power audioamp modules 1 01184/2 Stereo pre amp formagnetic, ceramic and auxiliary inputs

illus OUR PRICE

pup 1 00 f7.65

10 + 10 AMPLIFIER KITAn opportunity to buy a 10 watts per channel stereoamplifier kit winch is suitable for use with a ceramiccartridge The amplifier utilises proven Mullard modules andis available at a very competittve price The amplifier kitcomes complete with instructiors and includes a MullardLP1183 stereo preamplifier module, two LPI 173 poweramplifiers with integral heatsinks. a power supply,Zobel networks, front and back mounting panels, a finishedfascia panel, all control potentiometers (bass, treble.volume and balancel, switches, input, output and headphonesockets, wire, and an easily assembled wrap around cabinet

to house the finished unitSize approximately

x WY" x4"p,pf12.25

LCD Solar 5 function with badditestemless steel finish case and strap

LCD Solar Chrono 9 function with backlitestainless steel finish case and strap

Mon stop watch 9 function with back Icestemless steel finish case and strap

Solar Alarm LCDstainless steel case and strap.

AM/EM DIGITAL CLOCKRADIO Accurate 4 DigitElectronic Clock with LED

display Buzzer andsnooze timer £12.20

100 Watt Power Amp Module

Mains power supply for above unit

DECCA 70%v Stereo speaker kit comprising2 8" approx bass units 2 36' appro.tweeter Inc crossovers'VIDEOMASTER Super Score TV Gamewith pistol mains operation

PORTABLE RADIO/CASSETTE RECORDER.AM, FM with dock LW MW SW, VHFmains battery operation

ISP Radio Cassette recorder Mains/Battery AM/FMbuds m rrac auto stop

f7.40

19.55

f8.95f21.95

allialm 11114 50DWISACTTO AMMOPN 0

Wig ii" f3f14.25

13.60

f20.45

f15.95

f42.90

f24.50

0.60p&p f 2. 70

Size approx. 13-14" x 5Y4" x VA"50 watts rms. 100 watts peak output Big features includetwo disc inputs, both for :Ararnic cartridges, tape inputand microphone input. Level mixing controls fitted withintegral push-pull switches. Independent bass and treblecontrols and master volume.

ACCESSORIESSuitable mains power supply parts,consisting of mains transformer, bridgerectifier, smoothing capacitor and setof rotary stereo controls for treble.bass volume and balance L3 00

plus f 1 50 p&p

ACCESSORIES ARE ONLYAVAILABLE TO THOSECUSTOMERS WHEN BUYINGOUR BARGAIN PACKS

100 WATTMONO DISCO AMPSire applesIC's 4-x 10'r -Brushed aluminiumlama and rotary controlsFive venmal slide controls. master volume. rape lever nor level, deck level.PLUS INTER DECK FADER for paelect graduated change loom record deck No I to

No 2. or me area Pie lade level concur (Pat lets YOU heal next Aso beforelading it in VU meter monitors output level Output I CC wars RMS 200 watts peak

p00(405 f66.45

Two Way Speaker KitComprising of two 8's 5" *pros4 ohm bass Ad two 31/2" 15 ohm endrange tweeter with two 4.4.05MSS over capacitors

teBrLeigApisaolf ToplpuusntH1

PURCHASERS

THE IO 10 thAPLIFIER LOT

R C323 EDGWARE ROAD, LONDON W2

21E HIGH STREET ACTON W3 6NGACTON Mail Order only, No callers

ALL PRICES INCLUDE VAT AT 15%Al Hems laabloct to availability. Pries came at Ia.t 1.71

and subtect to change tett/tout notice.

NOTE Persons under 16 years not served without parent's authorisation

fARGAIN OFFERAriston pick-up armmanufactured in Japan.

j.Complete with headshell.Listed price over f.30.00.,

LOUR PRICE £11.95

P E2 50

Personal Shoppers EDGWARE ROAD LONDON W2 Tel: 01-723 432. 9.30am-5.30pm. Closed all day Thursdey ACTON Mail Order only No callers GOODS DESPATCHED TO MAINLAND AND II IRELAND 0010

ELECTRONICS TODAY INTERNATIONAL - J RY 1980 55

DIGITALFREQUENCY METER

This 0-150 MHz DFM design from Watford Electronics featuresfrequency, period, unit counter and time interval functions.A highly stable crystal timebase ensures accurate measurement.

The heart of this instrument is theIntersil ICM 7 2 1 6A, which con-tains all the timing, timebase

oscillator and control circuitry. InputA is the main signal input. Input B isused with the time interval functionand has a five volt TTL input charac-teristic. Pressing the ÷ 1 00 buttonswitches in a prescaler. To obtain thecorrect result the display readingshould be multiplied by 100.A double -sided PCB is used. To savethe cost of plated through holes, pinsare used to connect the two sides.Start by soldering in the pins, resistorsand capacitors, but do not insert thepower supply test link yet. The PCB isfixed to the rear panel with right angle

56

brackets. When all the componentsare mounted on the board, clean itwith meths or thinners. Check that

Input A

Input BSample RateSupplyAccuracyOverflow indicator

diodes, electrolytics, etc, are the rightway round and that there are nosolder bridges between tracks.

SPECIFICATION

0.3 to 20 Volts0-10 MHz (20-150 MHz

100 in)5 V TTL.5 Hz (all ranges)240 V AC.t 1 digitLeft hand digit decimal point.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 198a

PROJECT

B

PB1-100

+5V

R64M7

pin 2 IC1

R74k7

+ Q1BC108

C8 022u235V

BC108

R582k

T170n

TO R11

+5V

IC4c

R121k0

1 C610n

(CI does most of the work. The two dis-plays are driven directly by ICI, so theyrequire no additional drive circuitry. Thetimebase is formed by the crystal with C8,9 using the onboard oscillator.

When the +100 switch is pressed, inputA is connected to the input of IC6 via C7.IC6 is a Plessey emitter coupled logic(ECL) frequency divider with an onboardpre -amp. RS is used to reduce the inputsensitivity in order to increase stability.

Fig. 2. Range selection, using a CMOSswitch with enables controlled by IC2.

5V

R1410k

+5VRANGE

PB4 R1310k

IC5a

6

IC68629

IC4d

HOW IT WORKSWhen PB1 is in the 0-10 MHz posi-

tion, input A is connected to the pre -ampformed by QI,2 with C8, R6 and R7.Input B is a Schmitt TTL gate. Why TIT?TTL is used in preference to CMOSbecause the maximum input frequency forthe CMOS equivalent is around 2 MHz.

The range selection pin (pin 14) of ICIis switched to the appropriate strobe tine(D0-D3) by the CMOS switch, IC3, withthe enables controlled by IC2. PB4 is

!C5 IS A 74LSOO

AS10 K

+5V

C9100n D1

1N914

IC5c

NOTES:IC1 IS 7216A1C2 IS 4017IC3 IS 4066IC4 IS 74LS32IC5 IS 74LSOOIC6 IS 8629

IC5d

Cl1 pin 28

Fig. 1. Input A is the main signal input. Useinput B with the time interval function.

debounced by ICS and cycles the fourposition ring counter IC2. C9 resets thecounter when power is applied.

For function selection, pin 3 of ICI isconnected to the appropriate strobe line(DO,D3,D4,D7) by switches 6,9. R9, 10are used to increase noise immunity in themultiplexed inputs, pins 3 and 14.

The Hold switch 'freezes' the displayto make it easier to take a reading from arapidly changing input.

15

10

21

R1010k

1C34066

ICI pin 14

03

131

IC24017

114 0 11 02

121 1-0

13 9 18DI

61 1-1

3I 0 0

4 051

DO

L___ --J

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1 980 57

HOLD

+5V

RESET

Ae PB2°..

R3100k

P83

`.**.°.°

C439p

11/ 10MHz

R1+ R2

0 +5V

C556p

26

25

27

RANGE 0

FUNCTION0

INPUT A 0

INPUT B 0

13

14

28

Fig. 3. The brain of the DFM, theICM7216A chip. It even drives the dis-PloYs

DISPLAY

SOLDER

PCFig.

4. Fixing the display board to the mainB.

Fig. 5. Switch wiring for the time interval,unit, period and frequency functions.

TestingFit a 1 A fuse in the holder and applypower. Check for grey smoke. If all iswell, attach a multimeter (on the 10 VDC range) across C2. Take care -remember, parts of the PCB are live. Ifthe reading is about 5 V, switch off,discharge C1 and solder in the testlink. If the reading is wrong, switch

58

A

B

E

IC1ICM7216A

DP

D7

D6

D5

D4

D3

D2D1

DO

DISP 2 DISP 1

11-11-1001-100Lii

7 I-15

1920212223

5 0071

vtolc° s

off, check the mains switch, Cl, C2,C3 and IC7. Have a look at the trans-former and check the fuse.

With the link in place and thepower on, a zero should appear on theright hand digit (unless unit countermode has been selected, when theright hand decimal point will light).With the =100 button out, connect asignal of known frequency to input A.Note: to obtain a reliable reading thesignal should be at least 300 mV. Totest the prescaler, a frequency of atleast 10 MHz is needed.

Final AssemblyThe plastic mounting pillars in thebottom of the case should be removedwith a hot knife blade or cutters. Slotthe PCB with panel into the case bot-tom and drill out the fixing holes(6 BA clearance). Bolt the board into

Fig. 6. Make sure you get the polarity of thefrequency switch LED right.

place. The red perspex display filter(1 13 x 281/2 mm) is held in place bythe two halves of the case whenclosed.

In UseWith the time interval mode selected,input A starts the count and B stops it.A must go low before B to stop thecount. On repetitious signals this oc-curs automatically.

The instrument can be used tocount items on a moving conveyorbelt or to measure the speed of amodel plane prop. The prop can bemade to interrupt a beam of light.

The speed is then given by:

No of pulses (Hz) x 60 = RPMNo of blades

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

PROJECT Digital Frequency Meter

E 0

10

6

J6V

BR1

IN

1000u

IC7805

COM

OUT

C2 C3220u 10n

0TEST +5VLINK

Fig. 7. Now all you need is the powersupply to start DFMing. See text for detailsof the test link.

D=

Fig. 8. Component overlay.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

BR1 IS A TL005/7M

OV

0

PARTS LISTRESISTORS all YaW 5%R1,2 10MR3 100kR4,12 1k0R5 82kR6 4M7R7 4k7

14 10kR11 330R

CAPACITORSCl 1000u 16V PC

electrolyticC2 220u 25V PC electrolytic '

C3,8,9 100n polycarbonateC4 560p polystyreneC5 56p trimmerC6,7 10n ceramicC8 2u2 10V tantalumC9,10 100n polycarbonateC11,12 10u 35V electrolytic

SEMICONDUCTORSIC1 ICM7216AIC2 4017IC3 4066IC4 74 LS32IC5 74 LSOOIC6 SP8629IC7 78M05Q1,2 BC108DI 1N914D2 TIL211BR1 TL005Disp 1,2 4 digit common anode

display

MISCELLANEOUSDPDT push button switches (PCmounting) and buttons (8 off), 6waymounting bracket, one way moun-ting bracket, SPST toggle switch,BNC sockets (2 off), 1 A fuse (20mm) and PC clips, 6-0-6 3VA PCBmains transformer, 10 MHz crystal,case, cable clip, PCB.

59

PROJECT: Digital Frequency Meter

PHOTOTRANSISTOR

60

+5V

10k

LIGHTBEAM

Fig. 9. If you have a conveyor belt handy,you can count things running along it(gremlins, etc.) with this arnangement.

... And when you put it all together, this iswhat you get. Nice innit!This photo shows the completed prototypePCB, installed in the case.

.BUYLINESWatford Electronics are producing acomplete kit of parts for this project,with everything you need down tothe last nut bolt and knob.

Your Watford Electronics DigitalFrequency Meter kit will cost £64.50+ VAT.

The bsck panel, which carries the inputs,input attenuator and hold and reset buttons... and power switch, of course.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

NEW FROM MAGNUMDIGITAL INDICATION of RADIO FREQUENCY using a uniquecombination of FUTABA FLUORESCENT DISPLAY (the 'GreenOne') and OKI COUNTER/DRIVER.

Combination 1OKI MSM 5524RSOLI MSL 2318FUTABA 6 -LT -09Crystal

Special Price Offer £21.38

AM, FM, SWPre -Scaler5 digits + MHz, KHz3.2768 MHz

Combination 2 Special Price Offer £18.32OKI MSM 5525RS AM, FMOKI MSL 2318 Pre -ScalerFUTABA 6 -LT -06 31/2 digits + MHz, KHz + AM,

FM

Crystal 6.5536 MHz

Combination 3 Special Price Offer £24.57OKI MSM 55271 AM, FM, SWOKI MSL 2318 Pre -ScalerFUTABA 7 -LT -02 5 digits + MHz, KHz + AM,

FMCrystal 6.5536 MHz

Send today for your Combination (suggested circuit details andFREE I /C Socket are included) and enjoy "spot on" visualtuning.

OUR NEW CATALOGUE IS NOW READY Send S A E

iT166111JITI fiLJOID Ltd.DEPT. E.T.I. 1, 13 HAZELBURY CRESCENT

LUTON, BEDS. LU1 1DFTEL. 0582 2887

r TRANSFORMERSPanel Meters, Bridge Rectifiers, Power Supply UnitsMultimeters - Semi Conductors - Timers - Safebloc

Minimum & Sub Miniature 50 VOLT (Pr: 220-240V)

Milli- Ref. Price Sec: 0-19-25-33-40-50V

amps No. E P&P Ref. PriceVolts Amps No. E P&P3-0-3 200 238 2.35 .60 0.5 102 3.36 .800.6,0.6 IA 1 A 212 2.75 .65 1 .0 103 4.35 .959-0-9 100 13 2.05 .60 2.0 104 7.05 1.100.9, 0.9 330 330 235 1.90 .60 3.0 105 8.35 1.100-8-9, 0.8-9 500 500 207 2.50 .65 4.0 106 10.60 1.200.8-9, 0-8-9 lA 1A 208 3.60 .65 6.0 107 14.85 1.400-15, 0-15 200 200 236 1.80 .60 8.0 118 19.95 1.60620. 0-20 300 300 214 2.50 .80 10.0 119 23.85 2.1020-12-0.12-20 700(DC) 221 3.25 .80 60 VOLT (Pri. 220-240)0-15-20, 0-15-20 IA 1A 206 4.35 .95 Sec: 0.24-30-40-48-600-15-27, 0-15-27 500 500 203 3.80 .80 Ref. Price0-15-27,0-15-27 1A 1A 2045.85 .95 Amps No. f P&P

12 AND/OR 24 VOLTPry 220-240 Volts

0.5 124 3.60 .801

0 126 5.35 .952.0 127 7.30 1.10

Amps Price 3.0 125 10.85 1.2012v 24V Ref. E P&P 4.0 123 12.10 1.400.5 0.25 111 2.05 .65 5.0 40 13.90 1.501.0 0.5 213 2.50 .80 6.0 120 17.35 1.502 1 71 3.00 .80 AUTO TRANSFORMERS4 2 18 3.80 .80 Input/Output Tapped 0-115-210-240V6 3 70 5.35 .858 4 108 7.20 1.10 VA Ref. Price

10 5 72 8.00 1.1012 6 116 1.10

16 8 17 1080 .60 1.2020 10 115 13.60 1.40

(Wens) No. £ P&P20 113 2.40 8075 64 3.85 .80

150 4 5.35 .95

30 15 187 16.60 1.4060 30 226 33.10 1 70

Input/Output Tapped0-115-210-220-240V300 53 8.95 1.10

30 VOLT (Pn 220-240V) 500 67 10.60 1.40Sec. 0-12-15-20-24-30V 1000 84 18.35 1.50

Ref. Price Also 1500/2000/ 3000VA

Amps No. E P&P MAINS ISOLATING (Centre Tapped &

0.5 1 1 2 2.60 80Screened)

10 79 3.35 .80Pri. 120/240V Sec: 120/240V

2.0 3 5.35 .95 VA Ref. Price

3.0 20 6.05 1.10 (watts) No. £ P&P

4.0 21 6.35 1.10 60 149 6.35 .95

5.0 51 9.35 1.10 100 150 7.35 1.20

6.0 117 10.85 1.10 200 151 10.85 1.20

8.0 88 14.10 1 40 250 152 13.05 1.40

10.0 89 16.35 1 40 350 153 16.05 1 501000 156 36.85 3 10

Please add VAT at 1 5%card and Access facilitiesBarclaycard and

7a William StreetBAYDIS Herne Bay. Kent

Herne Bay 64586ti,.., Trade and Education Welcome -

.0)

The NEW/Marshall's 79/80 catalogueis just full of componentsand that's not all . . .

.our new catalogue is bigger and better than ever. Within its60 pages are details and prices of the complete range ofcomponents and accessories available horn Marshall's.These include Audio Amps, Connectors, Boxes, Cases, BridgeRectifiers, Cables. Capacitors, Crystals, Diacs, Diodes. Dis-plays, Heatsinks. I.Cs, Knobs, LEDs, Multimeters, Plugs,Sockets, Pots, Publications, Relays. Resistors. SolderingEquipment. Thyristors. Transistors, Transformers, VoltageRegulators, etc., etcPlus details of the NEW Marshall's 'budget Credit Card Weare the first UK component retailer to offer our customers ourown credit card facilityPlus Twin postage paid order forms to facilitate speedyordering.Plus - Many new products and data.Plus 100's of prices cut on our popular lines including I.Cs.Transistors, Resistors and many moreIf you need components you need the new Marshall sCatalogue.Available by post 65p post paid from Marshall's, KingsgateHouse, Kingsgate Place, London NW6 4TA. Also availablefrom any branch to callers 50p.

Retail Sales: London: 40 Cricklewood Broadway, NW2 3ET. Tel: 01452 0181/2. Also 325 Edgware Road, W2. Tel: 01-723 4242. Glasgow: 85 WestRegent Street, G2 2QD, Tel: 041-332 4133. And Bristol: 108A Stokes Croft, Bristol. Tel: 0272 426801/2

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 Eli

INDEX 79THIS month's alphabetical extravaganza brings youup to date with the past year of excellent ETI projectsand features. Index 79 follows roughly the samegame plan as Index 78. All articles except Tech -Tipsand News Digest are included.

Projects are listed in alphabetical order. Featureshave been divided into categories for ease ofreference. For simplicity's sake each project or

Projects

AAIR BAND CONVERTER DEC p.76AMBUSH

Pt 1 APR p.61Pt 2 MAY p.48

AUDIO AMPLIFIER OCT p.55AUDIO DISPLAY AUG p.87

B

BATTERY INDICATOR JULBENCH AMPLIFIER AUG

CCABLE TESTERCAR IMMOBILISERCLICK ELIMINATORCLICK SUPPRESSOR

DDIEDIGITAL DIALDIGITAL MODULEDIGITAL TACHODISCO AMPLIFIER 100 W)DOUBLE DIEDYNAMIC NOISE REDUCER

F

FAILURE MONITOR /INDICATORFLASH TRIGGERFUEL LEVEL MONITORFUNCTION GENERATOR

OCTMAYAPRJAN

DECJANJANJANFEBMAYSEP

SEPDECSEPDEC

p.92p.67

p.23p.89p.41p.73

p.32p.49p.35p.23p.64p.26p.35

p.23p.97p.53p.20

feature has only been entered once, in the mostrelevant category. Although Readers' Designs areconstructional articles, they are listed under Fea-tures, because they are not ETI projects.

Computing Today is now a separate publicationand is no longer featured as an ETI supplement. Itscontents have, therefore, not been included here.

See you next year for Index 80.

GGUITAR EFFECTS UNIT

HHEADLAMP DELAYHEADPHONE AMPLIFIERHUM FILTER

L

LIGHT ACTIVATED TACHOLOG CONVERTORLOGIC PROBELOGIC TRIGGER

MMAINS SEEKERMETRONOMEMICROWAVE OVEN LEAKAGE

DETECTORMOTOR SPEED CONTROLLER

APR p.97

MARMAYDEC

FEBJANDECMAR

p.27p.77p.46

p.50p.62p.101p.39

JUN p.46JUN p.21

NOV p.85JUL p.47

NNi-Cd CHARGER AUG p.29

0OVERSPEED ALARM

PPINBALL WIZARD

SEP p.80

NOV p.24

62 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

INDEX

POLYPHONIC KEYBOARDPOWER METER

R

RADIO CONTROLPt 1Pt 1

RAIN ALARMREACTION TIMER

S

SCREEN HEATER CONTROLLERSOIL MOISTURE INDICATORSPEECH COMPRESSORSTAGE DIMMERSTRING THING

Pt 1Pt 2Pt 3Pt 4

T

JULMAR

MAYJUNEDECOCT

SEPJULOCTMAR

AUGSEPOCTNOV

TAPE NOISE LIMITER FEBTAPE SLIDE SYNCHRONISER FEBTELETEXT

Pt 1Pt 2

TIMERTOUCH SWITCHTRAIN CONTROLLER

Pt 1Pt 2

TRANSCENDENT DPX ,,see String Thing)TRITON 8K EPROMTUNER/AMPLIFIER

Pt 1Pt 2

TWONKY

VVIDEOGRAPH

wWHITE NOISE GENERATORWIND SPEED INDICATOR

Features

GeneralA HISTORY OF IGNITIONANALOGUE TO DIGITAL

CONVERSIONEARTH SATELLITESELECTRONICS IN MEDICINE

JULAUGDECDEC

NOVDEC

JUN

JUNJULFEB

APR

DECAPR

FEB

MAROCTJAN

p.36 ELECTRONIC WARFAREp.67 Gm REVISITED

IMPEDANCE AND PHASELIFE OUT THEREMAGNETIC AMPLIFIERSPARIS IN SPRINGTIMERADIO, HOW IT WORKS

p.61 RADIO IN CONTROLp.87 STANDING WAVESp.35 SURFACE ACOUSTIC WAVEp.75 FILTERS

RAF AIR TATTOOWHO NEEDS ELECTRONICS

p.89p.67p.47p.50

p.18p.62p.35p.64

p.41p.27

p.20p.41p.55p.93

p.42p.86

p.73

p 30p 79p.79

p.27

p.67p.85

p.45

Reviews

JUN p.62APR p.37AUG p.58JUL p.72MAR p.45JUL p.44MAY p.35NOV p.18MAY p.83

MAY p.19SEP p.50MAR p.45

BORIS IN CHECK JAN p.81CELESTION DITTON 662

LOUDSPEAKER NOV p.37CHESS MACHINES DEC p.61.CHESS MACHINESATARI CHESS CARTRIDGE DEC p.64BORIS DEC p.61BORIS DIPLOMAT DEC p.62CHESS CHALLENGERS 7, 10 DEC p.63CHESS CHAMPION DEC p.63CHESS MATE DEC p.62COMMODORE CHESSMATE DEC p.62VOICE CHESS CHALLENGER DEC p.63SHURE V1 5 Mk4 MAGNETIC

CARTRIDGESONY HA55 HEAD AMP

TAE88 PREAMPXL25 CARTRIDGEXL35 CARTRIDGEXL45 CARTRIDGE

STAR CHESSSUPEREX CLASSIC HEADPHONESTECHNICS SL 150 Mk2

Readers DesignsSAILING CLUB RACING CLOCKTELEPHONE CALL TIMERULTRASONIC LIGHT DIMMER

Circuit DesignANALOGUE DELAY LINES

p.19. BUILD A VCTp.16 CHEAP TRICKp.40 FORTY CMOS CIRCUITS

JAN p.87SEP p.28MAR p.75SEP p.28SEP p.28SEP p.28MAY p.54NOV p.36NOV p.38

AUGAPRJUN

NOVJANAUGJUL

p.79p.54p.55

p.29p.32p.34p.531

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 63

INDEX

LM 10 - APPLICATIONS OCT p.68 POWER AMP SURVEY APR p.19LM10 - BASIC CIRCUITS SEP p.16OP AMPS AND INTEGRATORS NOV p.91POWER SUPPLIES JAN p.27TEN 3080 CIRCUITS APR p.70TRANSISTOR OPERATING POINT JUN p.25

ComputingCELLULAR LOGIC IMAGE

PROCESSOR MAR p.33

Data Sheets COMPUTER SPEECH FEB p.15MICROSENSE

AY -5-1317 CHORD GENERATORDATA SHEET EXPLAINED

FEBJAN

p.55p.57

Pt 1Pt 2

AUGSEP

p.47p.43

IC SURVEY APR p.52 Pt 3 OCT p.27MCM 6810A 128X8 RAM JUN p.84 Pt 4 NOV p.80TDA 1008 DIVIDER /GATING

SUBSYSTEM MAY p.70

Audio ComponentsCAPACITORS JUN p.80

AUDIO MAGNETIC AMPLIFIERS JUL p.26 ODD ODES (diodes) AUG p.73LOUDSPEAKER PRINCIPLES JAN p.14 VFETs DEC p.25

BACK

NUMBERSTime to fill a few spaces on your bookshelf!The following issues of ETI are still available as backissues:1974 February, May, June, July1975 February1976 July, August, September, October1977 February, April, June1978 February, March, July, September, October,

November, December1979 All except February

If your binder is suffering from a severe case of missingETI-itis, you can get hold of any of the above backnumbers for £1 each, including post and packing. Markyour envelope Back Numbers.

BACK NUMBERSETI EDITORIAL OFFICES

145 CHARING CROSS ROADLONDON W1R 1RF

WHAT'SMISSING ?

and cost a mere £3.00 all Inc

145 CHARING CROSS ROADLONDON W1 R 1 RF

64 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

EC

TOP

PROJECTSi

1 + 2

TOP PROJECTSBook 1+2: £2.50 + 25p P&PMaster mixer, 100W guitar amp., lowpower laser, printmeter, transistor testermixer preamp., logic probe, Ni-Cadcharger, loudhailer. !scope calibrator,electronic Ignition, car theft alarm, turnindicator canceller, brake light warning.LM3800 circuits, temperature alarm, aerialmatcher, UHF -TV preamp., metal locator,four input mixer, IC power supply, rumblefilter, IC tester, ignition timing light, 50Wstereo amp, and many more.

Book 5: £1.00 + 25p P&Pamp., stage mixer, disco rrilixer,

touch organ, audio limiter, infra -redintruder alarm, model train controller,reaction tester, headphone radio, STE.,timer, double dice . . .

Book 6: £1.00 + 25p P&P.Graphic equaliser. 50/ 100W amp,modules, active crossover, flash trigiiier,"Star and Dot" game, burglar alarm, pinknoise generator, sweep oscillator, markergenerator, audio-visual metronome LEDdice, skeet game, lie detector, disco lightshow . .

ETI CIRCUITS Books 1 & 2Each volume contains over 150 circuits.mainly drawn from the best of ourTech -Tips. The circuits are indexed forrapid selection and an additional soction isincluded which gives transistor specs. andplenty of other useful dataSales of thispublication have beenphenomenal -hardly surprising whenthe circuits costunder 1p each!£1.50 + 25p P&P.

seculWILE

YSII

ELECTRONICS - ITS EASYCombined volume.This, our latest work, is a completecollection of our ever popular beginnersseries. Previously published in threevolumes.£3.60 + 50p P&P.

FROM INF PUBLISHERS OFELECTRONICS 10PAT INTENT. NORM.

En

CIRCUITS

Not

TOP PROJECTSBook 7: £1.25 + 25p P&PER II loudspeaker, CCD phaser, 3 -channeltone control, bass enhancer, continuitytester, bench supply, LCD digitalmultimeter. digital frequency meter, widerange oscillator, ETI wet, egg timer. housealarm, porch light, torch finder. lightdimmer, 18 metal locater, electronicbongos, puzzle of the drunken sailor, racetrack, ultrasonic switch, tic-tac radio, revcounter, Transcendent 2000, spirit level

ELECTRONICS TOMORROWComprised entirely of new material. theedition covers such diverse topics as StarWars and Hi-Fi! The magazine containsprojects for everyone - none of whichhave appeared in ETI - and a look at thefuture of MPUs, audio, calculators andvideo. How can you not read it?75p + 25p P&P.

electronicstomorrPuk, "P

ITEINTFRELTIRYNNIG

VLN,FLLNIN,...

ORDER FROMSpecials Modmags Ltd, 145 Charing Cross

Road, London WC2Postage and packing also refers to overseas. Send remit-tance in Sterling only. Please mark the back of yourcheque or PO with your name and address.

HAND HELD GAMES

WE HAVE MOVED - COMUNELSEE OUR NEW SHOPThe latest front the U.S.A.

PINBALL WIZARD*Still available *

Featured in Nov. issue of E.T.I.Home TV Game -B W Kit

Basic Kit £28.90Contains everything except box and con-

trolsBox & Controls - 03.90. Mains Adaptor- £3.90Play 7 games with 4 options on eachgame4 -Pinball games 2 -Basket. 1 -Breakout

Versatile car alarm kit E18.90See review in Hobby Electronics

NovemberCHROMA CHIME 24 tune door chimes kit

£10.50 Built £15.95C B Aerials and Accessories

Mattel Space AlenMattel Auto RaceMattel Soccer

£15.90£15.90£21.50

ENTERPRISE 4 in 1 £24.953 Games and calculator ia oneElectronic Mastermind £12.90U.F.O. Master Blaster . . . £24.95Amaze-A-Tron maze game . £18.95Touch Me by ATARI like Simon) £26.95Football ;two players) . . . £24.95ZAP missile game £11.95DIGITS like Mastermind) £14.95DESTROYER £16.95ALL GAMES HAVE SOUND EFFECTSEXCEPT MATERMIND AND DIGITS

CHESS COMPUTERSETC.

STAR CHESS T, V Game £63.35DATABASE Prog. T/V Game

NEW £89.95CHESS CHAMPION 6 Level £54.95CHESSMATE 8 Level NEW E59.95CHESS CHALLENGER 7 £99.00CHESS CHALLENGER 10 £160.00VOICE CHALLENGER NEW £230.00BRIDGE CHALLENGER NEW £290.00CHECKER CHALLENGER 2 £54.00CHECKER CHALLENGER 4 £90.00ATARI Video Computer £159.00ZODIAC Astrology Computer

NEW £34.95SI141106011 of Commodore Watches &

Calculators

COMPUTERS - Home,Business etc.

PET 8K £632.00PET 16K New Keyboard £776.00SORCERER 8K £747.50SORCERER 16K £874.00SORCERER 34K E987.75SUPERBOARD II 4K £216.20UK101 Kit 4K .

£251.85Built 4K £303.00NASCOM 1 Kit £189.751 Built ...... £247.25NASCOM 2 Kit £339.252 Built . £396.75HEATH W1189 £P.O.A.Keyboard, VDU, Floppy Disc 16K all ,r,

One

PRINTERS: FLOPPY DISC: BOOKS

* We would like to wish all our customers a MERRY XMASand HAPPY NEW YEAR *

Please note our new address from 10th December 1979

S.A.E. EnquiriesPlease allow up to

r""h k".'l 61 BROAD LANE, LONDON N.16 4DJ 21 days for deliveryDay 01-808 0377; EVe 01-889 9736

BIO ACTIVITYTRANSLATOR TM

* Experience the unique MusicalForm of plants.

* Hear the beautiful patterns ofsound created by their naturalresponse.

* Easy to operate, internalspeaker, battery powered.

Natural Bio Electric signals, generated withinthe plant, are monitored by an electrodeattached to the leaf. When amplified andfiltered, a VCO, VCA and other exclusivesynthesiser circuits are controlled by the plantto produce tracking sequences of notes. Thesefollow in pitch, rhythm and volume the everchanging signal from the plant.

A Biological Amp lifer and Sound Synthesiserin oine Instrument

Components include: 6 IC's, 3 Transistors, 11 Diodes, 19Capacitors, 50 Resistors, PCB, L.S., all Hardware and pro-fessional teak finish case .Ready assembled £35.:25 or kit form £27.35.

NEW! PERIONISER -

Battery operated, pockeKit £19.50.

ONAL NEGATIVEend for detailssize. Ready assembled £25.00.

All prices include P. &P. and 'V.A 1- Please allow 21 days for delivery

JEREMY LORD ;SYNTHESISERS LTD.(Dept. EJ)

3 Charterhouse, E Itringh am Street, London SW18 1 TD

TRAINIAMSOLVES CAR IGNITION

PROBLEMS ...The BC&H Universal is an electronic ignition system based on

the latest developments in high power switching transistorsand silicon chip technology. The unit is designed to perfectly

match any existing ignition installation and to improve itsperformance at all engine speeds, without creating newproblems

DESIGN FEATURES ...Ruggedised design allows use on any car, bike, boat or stet -Wineryengine, its performance is not affected by water, acid or corrosion.Works from -50° to + 100°C and with voltages from 4v t6 20v. Willwithstand shorts, open circuit, or reverse battery connections. Noadaptor or rewiring is needed.

INSTALLING ...No adaptor or rewiring is needed, even if your car has an electronictachometer or rev counter. Existing radio suppression can be retained.No change is required from the manufacturer's recommended plugs,plug gap, coil or engine timing. It works with all 2 and 4 stroke engines(piston) with from 1 to 12 cylinders with negative or positive earth. Allthat's needed is a coil and a set of points. That's why it's called the-Universal-. The unit simply clips on to the coil and the wire.Complete with terminals, are connected simply to coil + and -.ground and points, easy to install and easy to remove. Complete detailssupplied

SPECIAL OFFER ORDER FORMPLEASE PRINT CLEARLY

Mr./Mrs./MissPlease accept my order forIgnition System /s.DI I enclose cheque tovalue of £

Debit my Access/Barclaycard.

All Cheques and Orders to'.TRANSAM LTD.12 CHAPEL STR.LONDON. NW101.402 8137

Address

Credit Card Accourit No.

11111.11111111111]

11

BC aH Uniinductive. Silico

Electronic ignition

0 TAKESINION

From conventional ignition1. To electronic ignition.2.... to the BC&H Universal!A SIMPLE AND PERFECTLYBALANCED IC ELECTRONIC

IGNITION SYSTEM Better performance

Better fuel consumption.I. Smoother power delivery.III Easier starting.4111 Lower maintenance costs.40 Less HT leakage.41 Less radio interference.ONLY

E1 9.95 VAT+ 50 P&P

66 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

NEWS

MICROFILEThis month Henry Budgett takes the plunge into the

language war and brings you the latest Triton news.

Astrange month this one and no mistake. There havebeen lots of little snippets of information drifting inon the wind, varying from general interest to specific

details, but with the proliferation of trade shows that alwaysoccurs at this time of year much has tended to be "comeand see". As I have mentioned in the past, the majority ofPersonal Computer shows in this country have tended tobecome carbon copies of each other so I hope to bring alittle difference to this month's proceedings by not men-tioning any!

Television's Epitaph

It was with a great deal of personal sadness that I learnt ofDr Chris Evans' death last month. The return of ITV withtheir series "The Mighty Micro", taken from his recentlypublished book and presented by him, will probably be afitting epitaph. I was fortunate enough to work with him forover four years prior to joining Computing Today and, fromthe first couple of the episodes that have been shown so far,I think that his prime skill of presenting complex informa-tion simply is going to make the series a great success.

Although the series will break no new ground withanyone familiar with the micro as a tool, it already has theappearance of being the "Working Man's Guide to NewTechnology". If it succeeds in getting over the fact that themicroprocessor is by no means the weapon that certainareas of the popular Press tend to scream about then it willhave achieved what I believe is its main aim.

Chris had not been in the best of health for nearly a year,but his sudden and untimely death has removed a greatsource of energy and interest from the computer world. I

hope that the rest of the series maintains the level ofinterest that it has already set.

Program Or LanguageA raging controversy is taking place at the moment in thepersonal computer pages of many publications. The sub-ject under the spotlight is what will replace BASIC as thenext computer language for the home computer.

Claims have been made in support of everything fromPascal via LISP to FORTH. In fact the vast majority of theseclaims reveal one simple fact - not too many people in thehome computer market know as much as they would like usto think!

Before you think that my head is expanding at analarming rate, let me explain.

Your average computer doesn't really give a proverbialmonkey's about what language you use because all itknows about is a series of binary digits that conform toeither its internal instruction set or are data for it toprocess. The only reason that computer languages wereinvented was to save us mere mortals from going mad overvast quantities of binary. The next logical stage up from theactual binary language, machine code as it is generallycalled, is Assembly Language. This consists of mnemonics,'or short groups of letters, that remind one of what thebinary code does. It is obviously easier for someone who:talks in a complicated language like English to understand.something written in letters than as a string of ones andzeroes. Most assembly languages follow roughly the sameformat and it is not too difficult to convert from say SCM P toZ80.

At this stage in the game we find what are called HighLevel languages, or as I prefer to call them SpecialistLanguages. These become more like the language that isspoken by the people who use them and this is the realpoint of this little discourse. It is a strange fact that thiscountry is about the only one to have any expertise atmachine code level in the home environment. The Ameri-cans, who are supposed to have invented everything fromthe wheel up, and indeed did produce the micro, seem todisappear whenever the words Machine Code are men-tioned. Why we are happy with it is a total mystery to me(answers on the back of a blank chqeue please) but theremust be some reason. I wasn't allowed near BASIC until I

had some knowledge of machine code and I suspect thatthere are many others like me.

11111

MICROPROCESSOR

Programming

Any bets for the next home computer bingo.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 67

NEWS: Microfile

The reason for the popularity of BASIC at the moment isbecause it is a well proven language, easy to write, manysystems support it and, above all, it is easy to understand.Try taking a program written in say Z80 assembler, anotherin BASIC and a third in APL. It is fairly certain that theBASIC program will be the easiest to understand, theeasiest to convert to your system and the easiest to change.I well remember being asked at an interview which I wouldprefer to alter, a program in BASIC or one in machine code,I replied "BASIC, because I'm more familiar with it." Myinterviewer replied "Right answer, wrong reason." I'llleave you to work out why!

The language which most people are touting to replaceBASIC is Pascal, and this is in my opinion similar to buyinga two litre car where a one litre one would do. The point tobe made here is that both perform exactly the same job butin a different way. If you were offered a choice of BASIC orFORTRAN you would look at the problem in a differentway, say, as a choice between a car and a lorry. Why,because they do different jobs. So the prime objective inthe choice is to select the right language for the task thatyou wish to perform and, without any doubt in my mind,the choice for the general purpose user is BASIC.

As a final parting shot in this argument I would furtherendorse the suggestion that any microcomputer soldwithout decent access to it's machine code isn't worthmuch. Whilst being harder to write it does give such a vastspeed improvement that it can be the only way to solvesome programming problems.

Try It OnA couple items of interest to those who have Tritons. Youcan now get a Pascal compiler for the system. It's a 20Kversion that plugs into the motherboard but it was deve-loped from a CP / M original which will also becomeavailable soon, so those of you with a CP / M system canhave it too. I'm digging my fingers in at the moment andwill let you have a report as soon as I can.

The second item is that disks are on the way very soon,again with the CP / M operating system. Both 5Y2 and 8inch will be available and you can have up to four in doublesided, double density format, which is a tidy number ofbytes of store. Keep your ears on for more details soon.

And finally two items, again both concerning Triton. Thefirst is just about the dirtiest trick in the book and I take theblame for it. I wanted to hang our printer on our Trion (wehave 5.1 so it's really easy), but I was a trifle worried aboutspeed problems. The fact was that our printer uns at 300Baud. I'm too lazy to change the switch and it looked asthough the delay in the software wasn't going to belongenough to cope with the carriage return. Well, beinghardware biassed I looked around for a solution, and I

found it! On the original Triton drawings you will see adotted push-button on IC4, that's the master clock, labelledPAUSE. Well, I thought, why not stick the printer's busysignal on there, after all it does the job. Even so sorry Mikeand all you at Transam but it does the job perfectly!

The final item this month before I go off to a couple ofexhibitions, drat I gave the game away, again concerns ourlittle machine. Having been dragged through the rigours ofthe disco, as seen in the papers, it has been banished of allplaces to Mount Etna, allegedly to control the temperatureof the police chief's bath water. ETT

LIGHTING & AMPLIFIERMODULES FROM L & B

01-689 4138YOU'VE ALL HEARD OF OUR SUPERB MODULES, AND IFYOU HAVEN'T, IT'S TIME YOU DID, SO READ ON!SHOWN HERE ARE A RANGE OF THE MOST RELIABLESYSTEMS ON THE MARKET.

LB31000SLC

£28.90

19 x 9.5 x 3cm

LB1000SL SOUND TO LIGHT.A SUPERB PERFORMING SYSTEMAT AN INCREDIBLY LOW PRICE.3 channels. 1000w each. Fully fused.Very high input impedance. Operatesfrom 'A to 300w sound input.Third order filters. Zero voltage fired.

£25.50LB81000LC19 x 9 5 x 3cmLB41000LS SEQUENCERLOGIC RANDOM SEQUENCER, WITH TWOSPEED CONTROLS OFFERING A WIDERANGE OF EFFECTS.

4 channels. 1000w each. CMOS circuitry.

Zero voltage feed.

LB31000LD

LB31000SLC SOUND TO LIGHT/CHASER.THE MOST ADVANCED SOUND TOLIGHT MODULE AVAILABLE, WITH

AUTOMATIC SWITCHING TO CHASEUPON ABSENCE OF A MUSIC INPUT.

3 Channels, 1000w each. Fully fused.Very high input impedance. Electronic filters.

5HZ to 70KHZ bandwidth. Operates from 'A to 300wsound input. Triac zero voltage triggering.

Master Vol / Bass/Mid/Treble/Chase speed controls.

LB31000SL £18.90

20 x 73 x 35

LB81000LC CHASERA FULLY DIGITAL 8 CHANNEL

CHASER, ALLOWING VARIATIONOF CHASE SPEED AND CHASE

RETURN DELAY.

1000w per channel. CMOS circuitry.Zero voltage fired. Can be footswitchtriggered. Additional modules can be

cascaded to form 16, 24. 32 chap. ect.

LB41000LS£14.90

20 x 9.2 x3.5 cmLB31000LD end 11000LD DIMMERS.FULL POWER 3 & SINGLE CHANNEL

LIGHTING DIMMERS FOR USE INCLUBS/PUBS/THEATRES/SCHOOLS, ETC.1000w per channel. Fully fused phase controlled.

Full input and individual Triac filters.

LB31000LD £12.90 LEI 000Lo £5.70

POWER AMPS, 250, 100 & 25W RMS.RUGGED TOUGH DEALINGPOWER AMP MOUDLES.

LB25010HZ TO 25KHZ

S/N 110DBTHD 0 3%

£29.50

LB100010HZ TO 30KHZ

S/N BOOBTHD 04%

£15.70

LB2525HZ TO 50K

S/N 90DBTHD 0.07%

£8.20PREAMPS

LBPA3. Complete stereo disco preampsystem. Comprising of L8iF1 deck mixers,mic mixer, deck and mic tone stages, micauto fade over decks. PFL. outputdrivers and its own regulators.LBPA2. General purpose 4chap. mixer/tone stage.

LBPA1 StereoHi-Fi System

LBPA3-M20 4 x 9 5crn

LBPA1 £14.50LBPA2 £13.50

LBPA3-M (magneticdeck inputs) £27.00

LBPA3-8 (ceramicdeck inputs) £27.00

LB25031 x 15 x 3 5crn

POWER SUPPLIESThree types of powerful supply unitsfor our power amps. Consisting of avarnish -impregnated mains trans-former and rectifier board (fuse pro-tected).

LB250PS £21.20LB100PS £12.20LB25PS £10.00

YOU REQUIRE A BOARD THAT'S MIGHTY COMPETITIVE, RELIABLE,MANUFACTURED FROM THE HIGHEST QUALITY COMPONENTS, OF HIGHPERFORMANCE, TESTED AND INSPECTED, SUPPLIED WITH CONNECTIONAND CCT, DGM AND GUARANTEED. IN TWO LETTERS YOU REQUIRE L & B.All prices shown are inclusive of VAT 45 WORTLEY ROADFor further information s a e to B WEST CROYDONTrade and Overseas inquiries welcome.1 L SURREY CRO 3EBPlease include 70p p 'packing with all orders TEL. 01.8894138

68 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

LOSING YOURSELFIS FUN

WHAT TO LOOK FOR INTHE JANUARY ISSUE.ON SALE DECEMBER 14TH.

Next month we present what we hope is the ulti-mate maze game. The programs designs a maze inplan and then projects it in 3D so you actually walkthrough it, hopefully finding the way out! Writtenin BASIC for the Triton it is fully documented forconversion to other systems. Once you get into yourmicro you may never get out so beware.

The famous game of Pontoon has been written in GAMING GAMESBASIC and we present it in next month's issue. A IN MICRO FORMbetter way to spend Christmas afternoon thanwatching repeats, on telly that is. Gamble your 50pon next months's issue for hours of fun.

SAILING A A brand new game of naval strategy combining airCALCULATOR to sea operations with conventional submarine

attacks. You will have to guide your submarinethrough the Pacific avoiding submarine hunters andsinking ships. A must for the sea -dogs amongst you.

If you are following our MPU's by Experiment KEY TO SUCCESSseries this project is for you. A simple add-on key-board to replace the one on the Mk 14 is a must foreasy programming, and this simple project will savethose stubbed fingers.

O

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 69

Green sankGreenbank Electronics

(Dept T1 E) 92 New Chester Road, New Ferryvenal, Merseyside L62 5AG

(Tel. 051-645 3391)

TERMS, VAT. CWO. Clewoos ale pryoOlo to 6rtaliaok Eloctroilr.s. AM VAT WAl prices at (5% inept Woos stated otlwroiss. Pest etc: UK 30p 1+5, VAT o.Mpl per irks. Expert NO VAT NI old 30p (ENO. 75p rEwspol old £2.50oloodwro.Ydys. urnertiliet. evt depts. MC can 19100 Moo orders lee Immedloto661101 co papa)

UV EPROM ERASERS

Two easy to use units designed for boththe professional and amateur UV -prom user.

Features: Can erase up to 14 proms Special short wave ultraviolet tube Erase time variable between 5 and 50 minutes in 5 minute steps

(preventing pver exposure which may shorten prom life). Sliding tray carries proms on conductive foam. Safety interlock switch prevents the timing circuit from operating

and switching on the tube with the tray open. 'Mains on and -Tube On indicators. Smart textured case Complete instructions supplied

Supplied complete with mains plug and flex.Model UVI4I. Price £77.70

Aso available without timer as

Model UV140: Price £61.20

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COMPUTER BOARDSTM following is en extract from our leaflet M. 'M P4', which is wedeln.tree on request f 9" a V SAE helps, but is not Mal). SeeMacreproceuer section to the right for bowel prismsFPI many people the wide choice of Micro -processors now availehle Presents adolfrcult choice To understand any particular microprocessor in depth adevelopment system is almost essential however in the past to understandmore than one several separate development systems have had to bepurchasedThe reason that separate systems. one for each processor. have been necessaryis due to the fact that individual microprocessors have their own individualfeatures in one case to access memory a separate read strobe and write strobeis required. in another a read; write line is used in combination with acombined strobe called 'valid memory address end phi -2 With someprocessors. the same address bus can be used for both memory andinput/output ports under the control of a memory request or aninput/output request control lineNaturally. if a development system takes advantage of any of the particularunique features of any particular microprocessor, this makes it more difficult tograft some other unrelated microprocessor onto the same bus at a later dateA Universal Micro System provides a basic bus structure on which any onemcm-processor can be connected The system uses a CPU (Central ProcessorUnit) card which is separate from the rest of the system and this allows thesame memory and interlaces to be retained when a different MPU is usedThe basic system bus consists of data and address buses together with read andwrite strobes By locating the data input (Keyboard) and output (VDU) in thememory space then such chips as the 8080/Z80 family which normally useinput output ports gin now be used without any fundamental change to thebus land as a bonus users of these MPU s have all the ports entirely free for

their own purposes)The range of p c b 's includes boards to implement a memorymapped VDU.cassette interface. keyboard interface. PROM programmer and a number ofRAM and ROM cards All the cards are of International Sue 114 a 203 mm(41/2" a 8"1 except for the larger power PSU A power supply card This lattercard issued so that it can be bolted to the side of a standard 4" chassis modulewhich is then compatible with the other cards The cards have a standard43 -way edge connector with one position used for polarisationWe do not propose to defend the (relatively) small number of bus connexions1421 against such standards as the 51 00 I00 -position bus The S 100 bus.as it originated in America. is bigger and better It is also more expensive In thesame way a Ford Granada is bigger and better than a Ford Cortina but itdown n mean a Cortina isn I good value for money who knows - it may evenbe better value,The International Sue card is the recommended sire for most '3U' 19" racksystems These racks are made by Vero. Critchley. etc. and a variety ofmodules and blank cards are obtainable to aid individuals in customising theirown system (A convenient trade source of suitable hardware is the firm R SComponents but we would be nappy to supply in case of dill icultyIt is appropriate to mention that this range of cards is not meant to compete64th any of the excellent computer kits which can be obtained The purchaserof these types of kits simply acts as an unpaid (or at least underpaid) assemblyworker II the standard components are put together correctly the computerworks it they re not it down t In the end each and every one is virtuallyidenticalThe range of boards in the Universal Micro System are entirely different youchoose your microprocessor memory interfaces etc.. what addresses will beused you choose whether or not to use our software. somebody else s orindeed your own (Don I be too alarmed if your level of experience does notpermit you to take this sort of deciSPOOWIth confidence - we are always here tooffer guidance if asked. we II even tell you if the system is unsuitable I or yourneeds in the unlikely even, that it is I

As mentioned on the last page a brave attempt Res been made to begin thedesign of a Universal Micro System to provide a sufficiently flexiblearrangement to permit the system to grow o the years, and not to becomeobsolete overnight To permit this flexibility. ugerever possible patch areashave been provided on the boards A patch area is an undedicated dual -in -linepattern which can accommodate an extra integrated circuit for your own useOften these can be used to add some extra memory or some extra addressdecoding An extra supply voltage can be developed using an integrated circuitregulator or gates can be added to allow separate Memory Request andInput, Output Request control lines one memory card which does not alreadyhave this facilityOf course we know that there are many people who would faint clean away atthe thought of cutting printed circuit traCks adding extra integrated circuitsand boa of wire in the way described above but a is not for these people thatthis sort of system has been designed We would like 10 think of this system asbasis on which you can build your own personal design perhaps as anaiternatim to the use or Veroboard or etching your own pcb s(Further sections give an outline of each card in turn Although we nave in mindall sorts of exotic future developments (e.g high resolution graphics floppydisc controllers dynamic high.density RAM cards programmable VDUformats colour displays Light pens sound generators etc) we prefer to keepquiet about them until they actually exist All of the cards described actuallyexist and at the time of writing (September 19791 most are in stock (We planit so they are all in stock but people will insist on buying them without caringwhat havoc they wreak in our stock controall

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70 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

PROJECT

PROCESSCONTROLLERThis controller has myriad applications in electronic andphotographic work. It features an LED display which 'countsdown' and is easily visible in darkroom or daylight.

11(arious processes ..in fabricatingelectronic projects requiretiming a chemical reaction or

process - developing photoresist inmaking printed circuit boards being aprime example.

The TechniqueThe easiest way of producing a timedelay is by using a 555 timer IC, but aglance at the data sheets shows that itshould not be used for periods inexcess of 100 seconds. By using the555 as an oscillator and feeding itsoutput into a 4017 counter/decoderIC the maximum timing period can beincreased ten fold. The unused de-coded outputs can then be connectedto a column of LEDs which will give anindication of elapsed time.

Each pulse from a 555 clocks the4017, moving a high level along itsten decoder outputs, lighting each ofthe LEDs in turn. When the high levelreaches the last output it is used tooperate the relay and thus the timedelay has been multiplied by ten.

A permanently -lit LED has beenincluded at the bottom of the row toshow when the unit is on. This alsogives a better indication of elapsed

time in a darkroom, as the LEDs canbe seen to step towards a referencelight.

Four time ranges have been pro-vided with a trim pot on each one foreasy adjustment. The table gives thevalues for each trim pot and Cl, for avariety of times. The minimum time islimited by the time taken for the relayto operate, maximum time by thelimitation of the 555. In practice,times from 100 mS to twenty minutescan be achieved. For very short timesthe time elapsed indication will not bemuch use and the LEDs can be left offthe board.

Fine adjustment of the timing isachieved by adjusting the thresholdvoltage on pin 5 of the 555. When thevoltage on pin 5 reaches a set value,the output (pin 3) of the 555 goes'low' (i.e: the 555 triggers). This vol-tage is normally set at two-thirds thevalue of the supply rail, fixing the timeduring the charging cycle of Cl whenthe 555 triggers.

If the threshold voltage is in-creased, the time taken for C1 tocharge to the required value in-creases, and the frequency of oscilla -

SPECIFICATIONMaximumtime delay

value of C1

value of RV (1-4)

1 sec 10 sec 100 sec 1000 sec

1uF 1uF 10uF 100uF

200 k 2M 2M 2M

Table of values for C1 and R V1-R V4 required for differing timedelays.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 198071

FINE ADJUST C3

RV5 100n

SW1TIME

3 2 4 7 10 1 5 6 9 11

'SEC TEXT

C

BC547 80548 9C549 BC557. BC558

Fig 1. Full circuit diagram of the controller

STARTPB1

maws

01

RI 1/2

01-D4

+ C547025V

R51k

LED1

911

240VMAINS IN

240VSWITCHEDOUTPUT o

HOW IT WORKSThe timer consists of a 555 timer IC used asan oscillator driving a 4017 counter/decoderIC, the decoded outputs being used to drivea row of LEDs and switch a relay.

The timing period is set by the frequencyof oscillation of ICI. This is dependent onthe time constant of RV1-RV4 and Cl. Aseither of these components are increase.: invalue the time constant will increase and thefrequency adjustment is provided by RV5which adjusts the threshold voltage on pin5 of the 555. This voltage is normally setat two thirds of the supply voltage, but hereit is adjusted varying the required voltageacross Cl to the 555.

Output from the 555 is fed to the clockinput of the 4017. After each pulse a differ-ent decoded output of the 4017 goes high,lighting each LED in turn. After the tenthclock pulse the output on pin II of the4017 goes high. We shall come to what thatdoes shortly.

When power is first applied, the relaycontacts RLI/1 are open and the bottomLED (LED 1) is lit. When the 'start' buttonis pressed the 4017 is reset to zero by apositive pulse applied to pin 15. This pulseis provided from R3 and C4. Pin I1 goeslow, turning on the PNP transistor Q1, andthe relay operates. The now closed relaycontacts (RL1/1) short out the start buttonand sustain the power after the start buttonhas been released. The transistor also drivesthe reset line of the 555 (pin 4) whichcommences to oscillate. This ensures accu-rate timing of the first cycle.

On the tenth pulse from the 555 pin 11of the 4017 goes high, turning off Q1, stop-ping the oscillator, and the relay is de -energised. The contacts RL1/1 open remov-ing the supply to the timer returning it toits original condition, ready for the nextsequence.

During the timing period, the second setof contacts RL1/2 close and can be used toswitch up to 5 A using the relay specified.

72 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

PROJECT: Process Controller

tion decreases. Thus, the total timingperiod is increased.

What device you want to controlwith the timer will determine the typeof relay you use. This unit is capable,of driving quite large relays, however,'we used a commonly available typehaving contacts rated at 10A.

ConstructionFirst, you will have to determine fromthe table the correct values of RV1-RV4 and Cl to provide the times youwant for your application.

Next, mount all the componentstaking care to correctly orientate thesemiconductors. The LEDs are bestmounted by inserting them into theirholes and bending them over flush

with the edge of the PCB. The photoshows the way we mounted the LEDs.

The completed unit can bemounted in a variety of ways to suitindividual applications. Either in abox, together with its relay and amains female output socket for theswitched output, or on a panel with aremote transformer and relay.

To mount the unit against a frontpanel, drill a row of ten holes for theLEDs and four holes to line up with thetrim pots for screwdriver adjustmentof the timing. The start button, timingswitch and fine adjustment pot can bemounted anywhere convenient. Theboard should be mounted against thepanel so the LEDs protrude throughthe holes.

LEDIO LED 2

12 V AC FROM TO PB1TRANSFORMER START

TO RELAY CONTACTS

PARTS LIST

TO RELAY COIL

Resistors All 1/2W, 5% SemiconductorsR1 1M2 D I -D4 1N4004R2,4 4k7 D5 1N914R3 10k Q1 BC558, BC178R4 4k7 IC1 555R5 1k0 IC2 4017

LfD1-10 TIL22OR or similarPotentiometersRV1-RV4 See textRV5 10k lin pot

CapacitorsClC2,4C3CS

See text10n polyester100n polyester470u 25V electrolytic

MiscellaneousSW! One pole, four position

switchPB1 Momentary Push ButtonT1 12V, one amp transformerRL1 12V relay with two

changeover contacts

Setting UpHaving assembled the unit, all thatremains is to calibrate the ranges. Thisis easily done with the aid of thesecond hand of a watch. For shortertimes, say under five seconds anoscilloscope is best.

Monitor the positive supply afterthe relay contacts RL1 / 1 and meas-ure the time the contacts operate. Forother purposes it may be best to setthe ranges by trial and error, such aswhen the it is being used for a PCBdevelopment timer. In either case, thefine adjustment control should be setin its mid position when calibrating.

ETI

TO RV5FINE AD

Fig 2. Component Overlay for theprocess controller unit

BUYLINES

The switch SW1 can be any 'breakbefore make' rotary type. Suitableunits are sold by Watford and Maplin.The 12 V relay is not a critical typeand so readers should experience nodifficulty in obtaining one suitable.from their local component shop.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 73

1 CLOCK RADIOHow about a round clock radio which can double as a very smartdesk clock - as we can testify!To time, rotate one end of the cylinder to display the frequencyselected. Most of the functions are controlled by a push-buttonpanel and the display is a large, clear LCD affair.Made by Hanimex, the battery clock radio comes in white, white orwhite. It will lull you to sleep and then turn itself off an hour laterand waken you to the sound of Radio 1, or music if you prefer.

2 DIGITAL ALARMThis mains -only Hanimex alarm has a large 12 -hour display incor-porating AM /PM and alarm set indicators. You can have a dim orbright display at the touch of a switch. Fast and slow setting buttonsmake time setting simplicity itself. You can forget about knockingthese accidentally in the morning scramble to turn off the alarm, as alocking switch is fitted under the clock. A 9 -minute snooze switchcompletes the list of all mod. clock cons.

3 LCD CHRONOOur Chrono comes complete with a high grade adjustable metalstrap and is fully guaranteed.The LCD display shows seconds as well as hours and minutes. Pressa button and you get the date and day of the week.Press another button and you have an accurate stopwatch withhundredths of seconds displayed, giving the time up to an hour.There's a lap time facility, too - and of course a back light.

4 LCD ALARM CHRONOThis is no ordinary watch. It's a slim, multi -function, dual time LCDalarm chronograph.This model will show hours, minutes, seconds, date, day of the

not all at once of course. There's a night light, too. E16.95week, stopwatcii, split time, alarm and alternate dual time zone -not all

minutes, seconds and day of the week are displayedcontinuously, while the date will appear at the touch of a button.The alarm is beefy enough to wake you up in the morning and getyou to work on time (or wake you up when it's time to go home).

All prices include 15 0/0 VAT and postageExaniples of Marketplace offers can be seen at our Charing Cross Road offices.Please mark your envelope with the offer that you want and order separately from offers shown elsewhere in ETI

To CLOCK RADIO offerETI Magazine, 145 Charing Cross RoadLondon, WC2

Name

Address

To: DIGITAL ALARM offerETI Magazine, 145 Charing Cross RoadLondon, WC2

Address

MMMMMMMTo: LCD WATCH offerETI Magazine, 145 Charing Cross RoadLondon, WC2

Address

To: ALARM /CHRONO LCD WATCHofferETI Magazine, 145 Charing Cross RoadLondon, WC2

Address

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

MORE BIG VALUEFROM YOURTANDYSTORE

1000 OHMSNOLTS AC/DC8 RANGESHandy r wiltrtester forhome and work -shop.Easy -to -read two colour5cm meter, pin jacks for di8 ranges. Reads AC andDC volts: 0-15- 150-1000 DC current,0-150 mA. Resistance:0-100.000 ohms.Accuracy- ± 3% full scaleon DC ranges.

4% on AC ranges.Complete battery.22-027. REG. PRICE

TRANSISTORIZEDSIGNALTRACER

Spot circuit troubles awlcheck RF. IF and audiosignals from aerial tospeaker on all audioequipment. With 9Vbattery, instructions.22-010.

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igital frequency readout. 3 -step RF Attenuator. 6-' Inge preselector with LED indicators. SSb and CWle:modulation. Speaker. Code oscillator. Batteries (notncluded) or 12V DC. 20-204.

£229.95

You save because we design.manufacture, sell and service.Tandy have over 7,000 stores and dealershipsworldwide Over 2.500 products are made

6 -DIGITFREQUENCYCOUNTERCounts frequenciesfrom 100 Hz tower45 MHz with 100 mSgate time. Accuracy is3 porn at 25°C or lessthen ± 30 Mkz on 10MHz! Overload -protected 1-meg

input. Sensitivity, 30mV up to 30 MHz.

Req. 9V battery.22-351. REG PRIEI

£79.95DIGITAL IC LOGIC PROBE

Unique circuitry makes it a combined level detector.pulse detector and pulse stretcher. Hi -LED indicateslogic "1". Lo -LED is logic "0". Pulse LED displayspulse transitions to 300 nanoseconds, blinks at 3 Hzfor high frequency signals (up to 1.5 MHz). Inputimpedence: 300K ohms. With 36" Dower cables22-300.

REG. PRICE £1995DYNAMICTRANSISTORCHECKERShows current gain andelectrode open and shortcircuit. Tests law, mediumor high power PNP or NPNtypes. Gomo-Go test from5-50mA on power types.22-024.

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ELECTRONICS TODAY INTERNATIONAL - JANUARY 198075

AUDIOPHILEThis month Ron Harris has news of a vanishing thump, a speaker whichcomes with ribbons on and a cartridge which has a golden future.Videotone, Goodmans, JVC and Goldring get themselves involved.

IT is 6.30 am Monday morning and it is cold and dark onCharing Cross Road. ETI's editor walks through the stillair, ignorant of the frost gathering on his extremities and

the shuffling uncertain glares of the tramps in thedoorways.

Far away a burglar alarm rings unheeded, disturbing noone not even the rat munching happily on a crisp bag whichskips away with a snarl as the editor passes, eyes unsee-ingly fixed on infinity.

Dawn was gathering its strength behind Centrepoint(and the rubbish piles) as he reaches the office doors. Hestops suddenly and a mugger swinging an iron bar down atwhere the editorial head would have been, misses his mark,stumbles and falls down a flight of stairs into a cellar,stunning himself.

Head still in clouds, musing on the ill fortunes of life, ETIEd turned the key and meandered into the building, closingthe door just as a hungry cat leapt at him from the hall,catching it in mid-flight with the door.

"Rotten. That's what is is. Rotten. Everything has a flawin it,- he mused to the ringing walls. "Rotten luck is whatwe got. Rotten. Take for example that Coral H 300headamp I reviewed last month. Lovely sound, neatconstruction and well matched to the excellent MC81. Butis it perfect? Alas no. Rotten luck. Rotten. The de -thumprelay doesn't work on switch off. Sends the speaker conesheading for the far wall with no regard for any ear -drumsthat may be in the way. Rotten luck."

By now he was entering the offices, edging in as thesemi -sentient cleaning staff pushed out, demolishing a wallfitting on the way. As their communicative grunts echoedaway down the stairs the editor walked to his office passingthe Art Director slumped unconscious across his desk onthe way. Cause unknown.

Just as he takes his place in the Editor's Throne, butbefore he can doze off, the phone rings. It is Coral. They putthe designer of the H300 on the line. The unit is no longerpossessed of a thumping switch -off. The relay has beenrewired on all current models so that no nasties escape. Allthumps are de -thumped good and proper. The flaw isrectified. All is well. . . . Perfection at last.

The Editor flings the phone high in the air and runsyelling from the room, awakening some of the staff in hisuncaring unbounded joy.

Life is good after all. Nice one Coral.

Heed ye all the vision before thine eyes. Felicity Kendal. You musthave been expecting this for a long time. Mr N. Ashford of Leicesterhad the good sense to point out that although I have continuallyreferred to the beautiful lady, I have never actually published aphotograph of her to prove the point to heathens like him.

Well Mr Ashford, my thanks for the idea (excuse?) and I onlyhope you are suitably repentant. Ignorance is no excuse.

76ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

NEWS

Corals H300 head amplifier which can now be wholeheartedlyendorsed because the one fault - a de -thump relay which didn'twork on switch -off - has been dealt with by the manufacturer andall is now well.

Apart From All ThatYes, well, I'm back from unbounded joy - all too soon. Itwould take Felicity Kendal's smile to keep this cynical soulin Nirvana longer than a brief moment or two. All else is butdross after all. 'Music to sooth the savage editor', etc, etc.

Some nice things have happened this month in therealms of things hi-fi. Two new sets of loudspeakers areworth a mention for starters. Goodmans launched the XB

The entire Goodmans XB range - all three of them! Prices vary from£95 for the 25 up to £139 for the considerably larger X B45 lurkingaway at the back of the photo. Stands are considered essential byGoodmans and are always a good thing anyway. All three arespecified for 10-60W RMS and a sensitivity of 9W (DIN).

range shown in the photo and on the initial listen in theyhave a crisp sound to them with a particularly clear upperbass. Good value for your diminishing pound.

JVC also have some new speakers to follow last month'stuners, and their claim to fame and notice is the use of aribbon tweeter unit, the principle of which is of interest. Foronce even my own stubborn nature does not tell me I couldimprove on the company's own explanatory verbiage. So

Getting RibbedIn the ribbon tweeter the diaphragm is a piece of thin film(12u - poly resin) of which the voice coil (18u -aluminium foil) is an integral part. This single unit has amoving mass of 0.048g - which is between 5% and 20%of the moving mass of a conventional tweeter.

The diaphragm is stressed to ensure constant surfacetension and sandwiched between two sets of magnets ofhigh efficiency and linearity.

Current entering the tweeter flows through the coilbonded onto the resin film and, with minimal transmissionloss in the coil, the diaphragm can produce movement withhigh efficiency.

Transient response is excellent, since the entire surfaceof the driver is driven to displace air and a (cast aluminium)horn is used to aid sound dispersion.

Intriguing, eh?There are three models in the new Zero range, a Three,

Five, and Nine floor standing version which I would verymuch like to get a listen to somehow. I will have to hopeJVC can help. At £375 each they are a little over the top tostop a shop and try one.

JVCs new Zero -5 loudspeaker incorporating the new ribbontweeter unit of which they are so proud. Sounds Isodynamic to me.

If you're about to buy a pair of headphones for anythingunder £35 - then don't. Instead, hang onto your moneyuntil you've read next month's Audiophile. A little box withMDR -3 written on it, which arrived here very recently,could make you regret doing anything rash. Let me besneaky and refuse to reveal anything other than that if youwant your phones to be comfortable, compatible with anyamp, have an excellent transient response and cost £1 7then anything you do now might be a mistake.

It is a safe prediction for me to make that the MDR -3 willcompletely change the headphone market place upon theirrelease. You have been warned!

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 77

Goldring G900IGC

Whatever next. Gold plated ABS plastic boxes, containinggold plated cartridges. How to make an impression in oneeasy lesson and lots of pounds sterling.

The precious metal approach was adopted by Goldringto enhance the presentation of their new IGC (ImprovedGroove Contact) cartridge. This is basically a G900SE IIbody with a whole new, highly expensive, stylus assembly.

Called a Van den Hul point, the stylus is of the 'GothicArch' type such as employed in the Shibata type, but with acompletely redesigned profile to further improve groovecontact and better recreate the cutter head profile.

Goldring have taken an amazing amount of time, troubleand money out of the bank over this stylus. The shape itselfis computer designed, the work having been done by theDutch physicist after whom it is named, and the companyspent a long long time searching for a supplier for the veryhigh grade of diamond employed.

TA

Above: the Van den Hul stylusprofile from the side (left) andthe front (right) showing theclose approximation to the cut-ter head shape.Right: comparative groove con-tact for the Van den Hul and theelliptical type of stylus.

Finally it has all come together at once, and here wehave the result - a cartridge with claimed attributes ofreduced intermodulation distortion due to its line of contactwith the groove being straight and perpendicular, betterdetail (especially at HF) due to its minor radius of 4.5microns as compared to 7 microns for an elliptical point andreduced record and stylus wear due to reduced frictionbetween the two.

As my one faithful reader may well recall I value theG900SE II as one of the best examples of a moving magnetcartridge around and here they've been and gone andchanged it. It's enough to drive a man to bacon butties andbromide in his tea (almost).

It is with trepidation and wonder that one should open agolden (Pandora's?) box. Beware of Greek postmen bearinggifts and all that.

Making An EntranceIt certainly entranced me seeing that bright gold bodyclasped firmly to the bosom of the SM E. Setting up the unitproved to be no trouble at all, but that mounting bracketlooks as wrong now as it did on the first G900 I tried.Alright, so I know it only looks that way and I cannot fault it

technically but that don't quiet the vague rumblings ofdiscontent somewhere south of what passes for myconscious mind.

I ran the cartridge through a series of response anddistortion tests which only went to prove how pointless it isto publish a graph which is to all intents and purposes astraight line and from which not one jot of informationabout the cartridge's performance - other than that it has atextbook frequency response - is to be gleaned.At 1.3g it passed every tracking test I could put in its way

and sailed unconcerned over 99% of the 'murder music' I

fed it later. An almost incomparable tracking ability then(good improvement here). As a guideline I'd say the IGC isa better tracker than the V15 IV - but only just!

What A Set -UpAs part of their 'blurb' Goldring make the astoundingassertion that 'due to the IGC's inherent ability to follow therecord grooves exactly it will obviously pick up recordblemishes also. In order to extract the best from thecartridge, therefore, we recommend that ONLY records ofthe highest quality (such as Enigma Supercut series) shouldbe played.

Include that ONLY and discount nine -tenths of yourmarket, Goldring. I must say that I found the IGC as tolerantof bad software as any top quality cartridge. It did notemphasise 'blemishes' in the slightest, much as that textwould have led me to expect it to. I can see what they'regetting at but instead of giving the impression of a superbperformance, fit for Superdiscs, in my opinion they areneedlessly accusing their own product of a touchiness itdoes not possess.

Detail,DetailTo be able to form a valid opinion of any piece of hi-fi,

one needs a reference against which to compare perfor-mance and in this case that role was filled by the CoralMC81 moving coil cartridge. In addition I was interested tosee how the new 900IGC gared against its predecessor, theG900SE

78 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

NEWS: Audiophile

In a direct comparison with the Super -E, the IGC was atfirst listen little different. However, the two were at oncedistinguishable and as the minutes ticked by the virtues ofthis new point began to make themselves apparent.

The sound is a beguiling one which leads you deeperinto the music the more you listen. It has a considerableability to portray that elusive thing called detail, and thetreble is a good deal better than either the G 900SE II or thatDecca device, being smoother and more accurate. Cymbalssound more like cymbals (rather than a burst of metallicwhite noise).

The difference is not one which leaps from the loud-speakers but is of the kind that makes hi-fi livable with for along long time as opposed to until the gloss wears off thepower switch.

It will also build a following devoted to the IGC I think.Bass quality is simply very very good and little changed

over the two models.Having stayed ahead of the competition this far the Coral

beckoned confidently, and the SMEs were appropriatelyarmed.

Coral In Deep Water

Let me say now that the Coral is a more expensivecartridge and one which I feel gives a performance which isworth a great deal more than its purchase price. It was nodisgrace therefore for the 900IGC to fail to better itsubjectively. Indeed the comparison did it proud indeed.

The main difference is one of those things difficult toexplain but immediately audible. The MC81 sounded atease with whatever music it was playing and somehow lesslike a hi-fi cartridge. I avoid the word colouration deliber-ately as being inappropriate.

One area where the IGC did take the decision, and all butunanimously too, was the bass. It just goes down further -reaching the parts which moving coils cannot refresh, andwith good control to boot. To put it bluntly windows rattledmore with the Goldring!

The only thing we could find to criticise was that the IGCis on the bright side of neutral, being characteristically veryclinical in its approach. The rendition is excellent although Ifear some of the -valve brigade" may find it a little cold. Asmall thing to hold against such radiance.

SummaryOverall then the Goldring is a very fine moving magnetdevice and one which many people - including me -preferred to such moving coils as the 777EX and even(shock horror) the Entre 1. It easily bears comparison withthe best of current moving magnet cartridges and indeed,in my opinion, has no peer in this realm.

It is difficult to find anything remotely detrimental to sayabout the cartridge and very easy indeed to go on praising itI shall thus refrain from both and finish by congratulatingGoldring for improving an already worthy product.

All they have to do now is 'to convince people to listen tosomething other than the 'revered few' repeatedly fawnedover by the more 'partisan' press.

The 900 descends. Even the stylus assembly is posh! The carrieris in a translucent green if you please. If this lot doesn't get in theDesign Centre they must be all mad blind twisted and dead.

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NO 2

$5.00 s2,5!3' £ 1 .50

Each volume contains over 1 50circuits, mainly drawn from the best ofour Tech -Tips. The circuits are indexed

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Ell .50+ 25p P&P

Specials Modmags Ltd., 145 Charing CrossRoad, London WC2Postage and packing also refers to overseas. Send remit-tance in Sterling only. Please mark the back of your chequeor PO with your name and address.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 79

Car AudioManual

MW/LWFull medium and long wave tuning. Com-plete with speaker and mountings. Suitablefor positive or negative chassis. Latestmodel

£10.25 +Post ,110, VI

-..--,Push -Button

. ---r... .1-

MW/LWDii iii. i

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£15.95 + £1.00Post

Stereo FM/ --

Cassette+ MW

...

Standard cassettes and FM in stereo plusmedium wave. Tone and balance controls.Fast forward facility on tape. Adjustableshafts. Suitable for 4 or 8 ohm speakers (notsupplied). This model is discounted else-where at £50 up.

.00£40.95 + P

£1ost

StereoSpeaker Set '....

Suitable for above £4.00stereo unit. Good qualityin surface mounted (pair)casing, 5W nominal,3W peak. + 70p Post

Telescopic Car AntennaMulti -section standard type, suitable forangled mounting with locking key.

£1.60 + 30p Post

Metal Detector-* Induction Balance Model

Built with sensitivity up to 10in onsingle coin; fitted with speaker andmeter; PP3 battery; 7in dia. searchhead. Telescopic stem. Excellentpin -pointing, positive reaction tonon-ferrous, negative reaction toiron. This model's normal price is£39.95!

£24.50 + E1.00 Post

All goods guaranteed one year.10 -day money -back offer. Goodsex -stock at time of going to press.Callers by appointment only please.Send s.a.e. for illustrated leaflet.

Minikits Electronics Ltd.6d Cleveland Road

S. WoodfordLondon E18 2AN

Hand held Computer gamesWe have selected the best

availableIt's you against the computer!

UFO MASTERBLASTERSTATIONMore sophisticated thanDESTROYER. Guide missiles todestroy UFOs which may changecourse or disappear!

£22.50

GRANDSTAND 4 -in -1Calculator/Auto Race/Code Breaker (as Digits)/Blackjack. Convenience -skill - Brainpower - Luck?

£22.50

GRANDSTAND ADAMFour games. Tune memory - compose your owntunes. Pathfinder - find your way out of a maze.Ditto - as Simon says, memorise and repeat asequence of notes. Bounce - competitive game forup to 4 players.

£22.50

MICROPROCESSORSFAIRCHILD GRANDSTAND

Video Entertainment Computer £72.50

Get the Midas touch and be theenvy of your friends

SUPERSWITCH Midas Touch Dimmer

The softest touch on the brushed aluminiumpanel of this beautifully styled control is all thatis required to switch lights on and off and tovary lighting brilliance.Touch Midas with the fingertips and the light ison. Touch again and it's off. Allow the finger torest on the panel and the light intensitychanges smoothly through a cycle from brightto dim and back again. Removing the touchduring the cycle sets the lighting at the levelrequired. Once set, this brightness level will bemaintained during normal on/off operations.Meets latest B.S. for R.F. interference.

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LCD PROGRAMMABLESWith non-volatile stores and memories and almostinfinite programmability (using FA -1)

1 500 hours continuous use battery life 51 scientificfunctions 1/4 x 21/4 x 51/2 ins Wallet

FX-501 P 11 memories,128 functional steps. 5 levelsO. 9 subroutines. 4 levels(RRP £64 95) E54.95

FX-502P 22 memories.256 functional steps 10levels Q. 9 subroutines 9levels (RRP £84 95 )

FA -1 Adaptor

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standard cassette tape reci a der imp, kit,

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MICRO MQ-11Specifications as AQ-2000 butwith "kiss" keys and smallercase 3/16th x 21/4 x 3'/tins.Wallet with window for display.(RRP £29.95) £26.95

HQ -21Six -digit clock, eight -digitcalculator. Full memory,percentage. Two AA batteries last I

year. 3/4" x 3" x 51/4".

R.R.P. £12.95 £10.95

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4 independent alarms, one with snooze feature.Nightlight. Calculator with %, square roots. Oneyear battery life. 13A x 51/2 x 23/4 ins (RRP £22.95)

cm at00000000000043 IR ILI

NEW SCIENTIFICSCOLLEGE FX-806 + 2 digit LC Display.Approx. 4,000 hrs.continuous use from 2 AAsize batteries.37 scientific functions, P toR, R to P, ENG key, Pi, cuberoot, 6 levels O. Memory. 3/4 x 3 x 57/s ins. (RAP £17.95)

£15.95FX-68 CardAs FX-80 but without ENGkey, 500 hrs. battery.3/ 16th x 2'/e x 35/8 Wallet(RRP £22.95) £19.95

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ockosra:00000iJO000t1 0 0 DO

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look ENG, FIX, SCI, RND and Random31 ea number keys.

st ", 5/32in x 2% x 4Yain11112,4"40 Ca £19.95

CASIO FX-3200As above but 10 digits

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TEMPUS SEE OPPOSITE PAGEFOR ORDERING DETAILS

80 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

THE NEXT STEP FORWARD IN TIMECASIO MEANS DIGITAL-New Lithium batteries lasting up to 5 years or more, totally eclipse mos

SOLAR watchesf FOR THE EXECUTIVE WHO DOESN'T WANT HANDS ON HIS TIME

-* THIS YEAR'S STAR BUY *THE NEW 83QS - 27BALARM CHRONOGRAPHOptional display of hours, minutes. seconds, date,am/pm; or alternatively: Hours, minutes, alpha day,date, am/pm. The automatic calendar is set for 28 daysin February. Casio's new Lithium battery lasts up to 4YEARS or more. The chronograph times in 1 /10 secondunits up to 12 hours, measuring net, lap and first andsecond place times. An indicator shows the chronographis running when normal time is displayed. The 24 houralarm can be set very easily to 1 minute intervals with anindicator to show the alarm is set.In addition the watch can be set to chime every hour, onthe hour, with a separate indicator to show this functionis on.A micro light illuminates the display at night time.This superb watch is stainless steel encased, has amineral glass face and is guaranteed water resistant to66 feet (2 at)

From Casio's New Collectionwe present two of the mostsophisticated executivewatches available today.

ALARM CHRONOGRAPHSDisplaying hours, minutes, seconds, day: and withday, date, month and year automatic calendar.pre-programmed to the year 2030.

81QS-33B5 year battery. Chromeplated case, waterresistant to 66 feet.(RRP £31.95)

1 / 100th secondchrono to seven hours.Net, lap and 1st and2nd place times.Selectable 12 or 24hour display.

24 hour alarm.Selectable hourlychime facility.Backlight. Mineralglass face.

81 CS -36B

As above but. Stainlesssteel case, waterresistant to 100ft (RRP£39 95 )

£35.95

Only Casio technology offers such high qualityat such low cost

M395 £27.95WE ARE NEVER KNOWINGLY UNDER-SOLD AND WILL TRY TO MATCH ORBEAT ANY OTHER ADVERTISED PRICEPROVIDING THE ADVERTISER HASSTOCKS.

IF YOU WANT A WATCH WITHChrome plating that may wear off after afew months;A plastic glass that will scratch and scuffand you may not be able to replace;A module with around 2 5% failure rate,that may take weeks to repair;A dubious or non-existent spares service;If you want a watch that the manufacturerdoesn't put his name on

THEN DON'T BUY A CASIO

There is no present like the timeF -8C TIME/DATE WATCH3 year battery. Hours, minutes,seconds, date, day, am /pm.Auto 28, 30, 31 day calendar.Backlight. Resin case/strap.Mineral glass. water resistant to55 feet. (RRP £12.95.)

£10.95N.B. This watch does NOT havea stopwatch

CASIO LADIES' WATCHESSuperbly styled stainless steel cases with mineralglass face, water resistant to 100 feet. LC Display ofhours, minutes, 10 seconds, seconds by flash,am/pm; And with day date and month

26CGL-20LGold plated

£53.25860L 12B

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£26.50

FARTHER TIME-FROM CASIO

CASIO CHRONOGRAPHSConstant LC Display o- hours, minutes, seconds,am/pm and day (12 or 24 hour). Dual time (12 or24 hour). Automatic cay, date, month and yearcalendar, pre-programmed to year 2030. Chrono-graph measures net, lap and 1st and 2nd placetimes from 1 / 100th second to 7 hours. Backlight.Mineral glass face. Guaranteed water resistant.

NEW MODEL950S -32B

4 year battery.Superbly styled brasscase, heavily chromeplated. Water resistantto 66 feet. (RRP£27.95.)

£23.95

R.

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;n CO.§ J Li

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11.

CASIO - for the man who isgoing places - fast!

F.200 SPORTSCHRONOGRAPHHou-s, minutes, seconds, am/pm; and with day, date andmonth auto calendar. 1 /_11_00 ---sec chrono to 1 hour. Nit, lapand 1st and -2nd place times.Resin case and matching strapMineral glass.Water resistant to 66 ft (2 at.).Silver oxide batteryRRP £17.95

£15.95

SEND 25p FOR CATALOGUE

Price includes VAT. P&P. Send yourcheque. P.O. or phone your ACCESS or

B'CARD number to: - TEMPUS Dept. ETI, Beaumont CEntre, 164-167 EastRd.. Cambridge CBI !BB. Tel. 0223 312866

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 81

AUDIO MATCHINGCIRCUIT

Make sure you and your hi-fi are well matchedwith ETI's universal buffer.

AFAIR proportion of problems inaudio set-ups can be due tomismatched output and input

impedances, when connecting equip-ment. If a relatively high outputimpedance source is fed to a lowimpedance receiver, distortion canoccur mainly because of the over-loading of the output stages of thesource. We can understand how thiscan occur by looking at Ohm's Law(this is a simplification of the situation,but nevertheless a useful analogy canbe drawn). Ohm's Law states that thecurrent through a resistor is propor-tional to the voltage across it andinversely proportional to its own res-istance.

ie. I =V/R

ImpedanceIt can be appreciated that if the res-istance is lowered with the same volt-age, then the current must increase.Likewise if the I /P impedance of a

82

receiver of a signal falls below that ofthe 0/ P impedance of the source thenmore and more current will be drawnfrom the source. The 0 / P stages can

Fig. 1. Circuit diagram of the buffer.

I/P

become overloaded, distorting thesignal and, if the impedance is too lowthe 0/P stages can be permanentlydamaged.

NOTES:Q1 IS 2113819Q2 IS BC212LLED 1 IS RED LED

SECOND CHANNEL COMPONENTS DENOTED BY PREFIX 1 e.g. 011, R17 ETC.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

PROJECT

Fig. 2. Component overlay.

o

PARTS LIST

A311U8 olaua

RESISTORS All 1/4W, 5% SEMICONDUCTORSR1,11. Q1,11 2N38 19R2,12 2M2 Q2,12 BC212'LR3,13 1M2 LED 1 TI L220R4,14 15kR5,8,15 2k2R6,16 27kR7,17 1k0

POTENTIOMETERS MISCELLANEOUSRV1 20k preset SW1 SPDT PC mounting

switch.CAPACITORS Phono sockets 4 offC1,11 1n5 polystyrene Box Vero type 202-C2,12 1u F polycarbonate 21048D.C3,4,13,14 10uF tantalum 16V Battery clips 2 off type F 'P3

HOW IT WORKSThe high input impedance of a field effecttransistor is utilised in the input stage to thebuffer. This is further increased by "boot-strapping" the amplifier, by inserting C2(referring to the circuit diagram) betweenthe source and RI. The capacitor is chosento be large enough to act as a virtual shortcircuit at the lowest frequency under con-sideration. This gives the effect that if oneend of RI changes in voltage, the other endof RI moves through the same voltagechange. RI is "pulled up by its bootstraps".

(A typical American term).RV1 allows a certain amour it of gain

because the overall voltage gait1 is givenapproximately by the equation

Av = R5 + RV1

R5

In our circuit R5 = 2k2 and RV1 = 20k,allowing a gain of approximately 1 0. RVIcan be further increased if required.

The opposite, however is not the.case - if tl-e receiver stage has ahigher impedance than the source, nodistortion wil occur.

Currently InThe ETI Audio Input Buffer providesthe facility of an impedance converter.Because of the inherently high inputimpedance (in the order of Megohms)the buffer is basically a high imped-ance source follower (ie. whateversignal is connected to the I /P willappear at the 0 /P). The 0 / P imped-ance is low and therefore will drivevirtually any amplifier.

The ideal buffer should give theoutward appearance that there is no-thing there, ie. it should introduce nodistortion, no matter what frequencyor amplitude of signal is being buff-ered, the only effect should beimpedance matching. To this end thefrequency response of the ETI bufferis quite wide, 20 to 200KHz(adequately covering the audio range)and it can accommodate signals up toabout 10 vo is pk. to pk. withoutclipping.

Although essentially a unity gaindevice we have included a presetresistor whose adjustment will give amaximum gain up to approximately10: overall making it a most usefuland versatile cevice (we hope).

ConstructionConstruction is straightforward if ourPCB design is used. Both channelcomponents are mounted on theprinted circuit board along with theON/OFF switch SW1, to reduce in-terwiring. Use screened lead for allI /Ps and 0/Ps and keep them asshort as possit le.

C2 must be non -electrolytic - weused polycarbonate for size restric-tions, and would recommend that youdo likewise.

Although a Verobox such asemployed here is perfectly adequate,in hum fields such as are found next tomains transformers etc, a steel boxmight improve noise performance.

In use ours gave no problems at allif sited sensibly. Eli

BUYLINESAll parts used in this design are stan-dard types which should be availableat your local stockist, without muchado.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 83

Freepost C FREEPOST ON ORDERS ACCESS

L4.11,1 Birmingham im VAT INCLUSIVE PRICESCASH

B19 1BR ADD 30p P&P CHEQUEELECTRONICS 021-233.2400 24 It-IR PHONE ANSWERING SERVICE

ALL PRICES IN PENCE EACH UNLESS OTHERWISE STATED

CAPACITORSElectrolytic Axial Leads Order Code-10% to +50% Tol. Cap 016 aF 4. V el.AF V i.e. 16 25 40 63

1.01.52.23.34.78.8 9 1

10 1

1522

91;

3347 11 13

68150 13150 10 31

220 11 26 36330 30 40470 23 32 47

WOO

21

253030

3959

64

1500 35 392200 42

Trimmers Order Cod*250V D.C. 14159 rn 0.540.4, laintature1.4 - 4.100 20 Cap BOB A

2 - 8pF 20 C. 808 82 - 20p6

5.5-59.5012231

Cap 808CCap 808

ElectrOly w Radial Leads-10% t0 50% TotAF V de. 6.3 10

.47

.681.01.62.23.3

4.78.8

101622 7

3347 868

100 9150 11

220

16

899

Order CodeCep 034 oF Volts

25 36 40 50 63

7

7

7 899

9 11

11

9

11

Electrolytic Can Type Order Code01.014, IEC Grader I, Low E.S.R. Cap HR of VW.

S.W.ed complete vorth Vertmal Futang0..1000010122000oF

470045010000oF72013450

4700oF100045F4700oF

15V16y25V26V25V

400700

RoPp14 5.840 85C ILIA 50° c984, 13.744.64 6.448.04 11.24

12.84 17.945.64 7.849.24 12.847.54 10.5A

238370215282469248393403

Miniat u re Low ValuePolysn Ana!, 1% Tol., 2635 DC Wkg.Careen le: Plate, 002,04. Low K, 100V DC Wk9.CWIPM :Plate, Hach., Med 14, 100V DC WIcg.Gwen. k c Mate, Rachel, 1496 6, 830 DC Wk9

pF 4241

1.21.261.

2 2.7

3 ,7531.94 .71108.882

'10121518222733aso

47666882

632 oF100120150100220270330390470560820820

100012001500190022002700330039004700500068008200

424IS18

1818is

201010201020

20202020202020202025252525

632 630

Order CodeCap 424Cap 632Cap 630Cep 629

Vols.OF 424 62010 27 012 2915 2918 3122 31 027 4233 4539 50

Polyester Radial Leads Order Code

Owned TYPS, C280/352 Style Cap 352

Moulded TYPO, 10.2mm Po. Cap 360 Volt.

oF 362 380 stF 262 260001 7 9

0015 .15 6 100022 22 9 11

0033 11

0047 .47 1400913 17

01 1.0 21

015 1.6 30022 22 35033047068

Tantalum Bmd20% Tol.

of0.10.720.47

1

2.24.7

102247

Order Codecap pp xF Vats

10 16 25 36

13

22

11

121618

1618

11

11

11

131822

INTEGRATED CIRCUITS4000 Buffered CMOS - High Spe40

4E14000 17 61E04044 84 4E14512 1104E04001 17 14E64046 106 4E04514 2504E04002 17 4E14047 87 4E14515 199HEF40064E14007

9517

4E040494E14060

4545

4E6451614E64517

101382

4E04008 80 4E14051 89 61E045184E14011 17 0FF4052 72 4E04519 5514E14012 17 11E64053 72 4E14520 944E14013 45 4E64066 49 4E64521 180ME F4014 94 4014067 390 4E04528 se0(14015 90 HE 04088 17 0664532 1204E04016 45 4E04069 17 4E64534 51015E04017 90 4E14070 17 4E14539 1104E14018 80 11E64071 18 4E14543 1554E14019 46 0064072 18 4E04565 794E14020 99 4E04073 18 4E04556 7B4E14021 65 4E14075 IS 14E04557 386viEF4022 82 4E14076 104 4E04585 974E04023 17 4E14077 17 4E14724 1714E04024 62 4E64078 18 4E640097 904E04025 7 4E64081 18 4E140098 734E64026 05 4E64082 18 4E640106 624E04027 45 11E14085 64 4E040180 1194E04028 71 4E04086 64 11E140181 1194E14029 90 4614093 50 4E040162 1194E14030 48 4E64094 175 4E640163 1194E04031 200 4E14104 166 4E040174 1194E14035 110 14E64502 91 14E040175 1194E64040 05 4E04505 571 4E140192 140

75 4E04508 184 00040193 140HE14041E04042 66 4E14510 1013 00140104 119

11E14043 80 4E14511 125 4E140195 119

CASES - Boss Industrial MouldingsSmall Desk Console - Boss Industrial MouldingsSlope Front Console. Recessed TopABS Base, CAN Brass Bushes. In OrangeIn.. Anonyms. Top Panel F W.11.15,60

W161, 096, 4391571 2140215, 0130. 047 1731 303

Order CodeCase 131641005 ORC..13161005 00

Plastic Boon - Boss Industrial Mould..Moulded Box and Close Fitt., F1.nyed LodABS Boo. CM Brass Bustin, and Lid In Orange

1112 15132 031 99L150 W80 1350 131L19015110 CAW 723

Plastic Boon with Metal LidsRwesh. Top 61o5485 Base. C/15 Brass Pushes, In Orewia1rrirn Alumnoum Top Panel Forgalwa Grey

L85 1556 D29 1121111 W71 042 150111311596 D53 208

Dieeast Boon131111017 Coo and Flanged 4.0Awr mown Boa end Lid on Nalutal Finish

111315433 031 124L152 W82 D50 215L19201113057 334

Small Desk ConsolesSlope From Console, Recessed TooABS Base, CAN Brass Bushes, In Orange1mm Alum.n.rn Top Panel Finished GreyNernt.117.00 Slots Inane

WI05 0143 432 1561 236W170 0143 432 1561 312W170 0214 432 1821 431

Order CodeCase 8162003 ORCase 81512005 00Case 81142006 OR

Order CodeCase 81514003 ORCaw 8104004 ORCasein...005 OR

Order CodeCase 131105003 NACase 8105005 NACase 81.5006 NA

Order CodeCase 8106005 ORCase 81656006 ORCase 81616007 OR

7400 T.T.L.

574005514015574025574035574045574055574065574075N74081,157409557410551411551412557413557414N574165574175574205N7411557425557426557427557428557430557432557433N574375574385574395574405574475N7443N

131414141816

3232161614

1614

2331

21

21

16

16

19

20202314

20232121301451

92

574445 921474455 855744645 85N744745 715744845 92574505 14574515 14574535 14574645 14574605 14

574705 28574725 19574135 28674745 24574755 34574765 30574805 325748361 63574855 80514865 25574905 405749145 5757497N 40574935 40574945 5T5749545 46574965 575741005 915741075 265741095 455741165 925741715 28

57412255741235574175557412655511285574132557414555741415574148557415055741515574153557415455741555N7415614117415755741585574160557416155741625574163557416455741655N 741136557417051474173557417455741755574180557418151741825

41P2N

91 57415785 3513 N74LS30N 1951 57418325 27

135 57415335 35122 574153714 35

77 5741538N 3561 5741840N 2777 51415425 6059 5741551560 5741554559 14741055559 5741573N

91 574187555741676557415785

43 57,1 -S035 19 N74158345 10643 511 L5015 19 5741585583 N7 441S025 19 717416885 3963 5: X 111.5039 19 57418905 5963 5 1 415045 27 57418925 7663 5 .7 415055 27 57415935 7686 1 i' 44190185 27 574159585 B2go 14 7415095 27 57416955 12686 617410105 19 57415107N 41

122 64741511N 25 574101095 4577 '147415125 26 574151175 4677 51418135 49 574151135 4555 57415145 74 574151145 4557 N74151514 26 574161255 53

205 57416205 19 574181265 5357 57410215 26 574151325 7691 5741822N 26 57415136N 49

40 14741%3N77 574194537 574195537 574198538 57419963,38 574224 467 574279 6196 574298.14

193 1117438, 7 g91 574386 548 5743e r:IN43 574312 iry

48 741 di48

OPTO ELECTRONICSLight Emitting Diodes, Indiyidu.1125" 13nyn1 Awl

GreenYellow

P100 M0unv19 Om to sun.

.2" 15nun1 RedGrewYellow

Panel Mounting Clop to sod

Photoresistors0001200661

Phototransistors

0057113052580629

PhotOCOOPIer

1013820

HARDWARESockets

8 Pon Low Prot.. Socket Tin14 Pin Low Profile Socket T.16 Pon Low Profile Socket Ty,

Heatsinks

indivicwal Tow for 1 705 50' C/WIndividual Type 10, 1 1066 10.5' C/WIndividual 100.70,1+103720310Individual Type for 1 T0126 17' CANWd.v.dual Type lo. 1 a 70720 17 -CAN

P.C.B. Components

Delo Pen. Blue ink, Slow Dry.,

Order Code

18 COYS418 COY9520 C0197

3 1E03

161830

5

2727273644

39

104

6744.313814N74151395574151535574131545 138N74131555 93574151585574101575574151585574161605N74101615574131625574161835574101114645741017055741817355741517455741817555741518164N74151905514101915574101925 119574151935 11957415194N IIIN/41019545 1191474151965 132574101975 1325741024014 205574152415 1061474152425 206574182435 206574152.1N 108574162515 117

9999es

939397

129

144117119720131141

119308117117

57415253N 117574152575 11757415258N 11757415260N 29514152615 321574152685 54574152735 143574152835 11757418290N 11757415793N 119574182913N 149574153655 111574183065 121

574183875 121

14741-536864 121

147415373N 173574193745 173N74183755 11757415378N 15657018386N 56N7415390557418393N574153955514154905574106705

1961913

207143239

CA3046 84CA30006 77

C43130E 99CA3140E 48C431896 193151301414 34LM3395 781113805 104LA1381461 198L1439005 7510C3403P 1565E531 131565.3430565555NE55655E566556570N14657114RC4136

7592866

171

486505146

T841205 BB

7041022 71310410348 13971.0810 8471084C5 156V474104 20UA74I CT 471147443C5 39

ZenerDiodes4005.5 C407.C3382088/B2079 Voltage 9

LINEAR VoltageRegulatorsW3090416) 119U472305 42U517805CU 781.14781203 7811478150J 781147912W 97U47915CU 97V478105CS 381.1781.1213 38U478115CS 38

Plessey I/C'sSL440 33151445SL131054.012SLI32051821SL82251624SL8300184051680SL16105116115L1612511621511826511630SL1640SLIM'016640508629

182245245389309910342232409245177177177239267177106200270475

C012 44COY9 4.C018 siLED, i Clop

95 0071395 0019,1

220195195

OC P 71BP x.75

79

165 C .D820

Ord III, Code

12 0IILSKT131111 SI, 14

16 1 311 SET 16

12

202626

26

511,4 5F

Sink TV2Sink 103sink TV4Sink TV5

98 Pen 33PC

RESISTORSCarbon Film, Fixed0.25W, 624 Values 180.105/, 5% Tol06W, 612 Values 100.0117, 10% Tol

Metal Film, Fixed0.5W. E24 Values, 501151, 2% Tol.28W, 112 Value, 100776, 5% Tol.

Metal Glaze, Fixed0.5W. E24 yaw/5,115.3351 5% Tol.

Order Code

2 each 100/1001 Mull 10/Value/ Res ROY.3 each 150/1001 Mull 10/Valuel Res 16137.

value

8 each 400/100 160... 10/Value) Res MR3016 each 800/100 Wluit 10/Valuel Res 1052

Value

16 each 800/100 111111 10/Vaiuel Res 0837 value

SWITCHESMiniature Toggle - HoneywellSPOTSPOT C/011SPOT D.5104 Bias To CentreSPOT Single Bias To Cent.SPOT BiasDPOTHOOT C/00DPDT Double Bias To CentreDPOT Singe Bost To CentreDPDT 11144

Miniature Push -C d KSP Push To Make, Moments,SP Push To Break, Mornentery

Order Coda

67 SW 84101181 SW 04102190 SW 84104190 SW 84105184 SW 84106199 SW 847011

111 SW 842021123 SW 8A2041123 SW 842051116 SW 842061

62 SW 853102 SW 8533

MAINS TRANSFORMERSSecondaries may 04 connected on senses orperallel to gove we. voltage 51.94P. n... 0220, 240V604 Clamp Type Construction 235 each

111.00 18.1, .11.411041 G.C. 54, 036. W35

04.50,04.5V Stecondarw000,0.000120,0.12V015V, 015V0200. 020V

Order Code

Trans 604 4580

2004 - Clew. Type Constrwhon 380.106

Appro. 16% Reguienon F.C. 70. 448. W40

0.4.5V, 04.50 Seconcleriw0.60, 0-80012V, 0.12V0.15V, 0.1500.17.50, 017.500.20V. 0.200

170150200

Trans 2004 4500

120150175

200

SEMICONDUCTORS5914 5

54001 5

54002 5

54004 7

54007 9541413 4

55402 15252711351 31

252369 21

2N2646 06

252926* 13

253053 19

253054 55253055 55253055Full ISO Test 95253442 155253702253704 9253705 102N3773 797253819 22

253810 39253904 9

255457 39

255459 35

40673 88AC188 2440161 0240162 4284W950 12008C107BC108 14

BC1C0C 18

BC109BC109B 19

BC109C 201BC148

BC158 10

8C177 17

80179 20BC182

BC1821 128C184 11

BC1841 12BC2I2 11

13C2121 12

10214 11

BC2141 1280547 13

006413 11

BC649 128C557 15

BC558 15BC070 ISBCY71 15

813131 3980132 39813139 39130140 39BFR90 33381065 2981050 17

BF 751 17

131Y52 20

B1065 2626111934 297709V39 5085020 21

C18960 7950551102 360491 80028 1180C35 105TIP314 48TIP324 54TIP41C 78T111420 7811P2955 75TIP3055 6011543 36276109C 16

VERO I' L ECTRON I CS PRODUCTS1.5" x 5" . 1" pitch Veroboard 71

3.75" x 5 " .1" pitch Veroboard 792.5" 1" . 1" pact. Veroboard 1513.75 1, .1" .140 Plain Board5:82- x :7) )" .1" pack v.0 0111 BoardSpot Fac cony.stn 115011 -on Tool f or .040 1001 pin135 Pms .114011001SS P.ns .014011001Verowl re K 11 110.0, 2.wre, 25-40.'1Vero*, 11 Combs 1251Verow .re . W.121

84

85/Pack68

13510714744/Peck44/Pack

454 /6 it109/Pack109/Pack

200.210690200.210720200.2107602007107814200-21084E203.210134203210151200210876200-2101782002134112200-213396200213400

Skeleton Presets, Miniature0.1W, E3 Values. 1000.051, Lin. Ver 0.1 Mountong0.1W, E3 Values, I000'15, Lon. 4orwontal Mounting

Skeleton Presets, Stoddard0.3W, E3 Values, 1000.4647, Lin. Verne.] Mount.,0.3W, E3 Values, 10011467, Lm. Horizontal Mounting

Potentiometer, Rotary0.5W. E3 Values. 162M2 Lon.0.250, E3 Values, 467.2M1 Log.

Potentiometer, Slider0.5W, E3 Values, 2024706 Lin.0 25W, E3 V.10.5,1630-1004.09.

Order Code8 Mm. Preset V8 M.n. Preset

value

11 Std. Preset V11 Std. Peel

value

39 Ro Pot39 Ro Pot Log

Value

45 Si Pot 1."45 5 Pot Log

veh.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

&tillFreepost ACCESSBirmingham VISA

B19 1BR CASHELECTRONICS 021.233.2400 CHEQUE

FULL SPEC KITTELETEXT DECODER

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TELETEXT DECODER Os 1

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I STATE OF THE ART L.S.I. CIRCUITS DOUBLE HEIGHT CHARACTER SELECTABLE FOR LEGIBILITY CHARACTER ROUNDING - EFFECTIVELY DOUBLES DEFINITION ULTRASONIC REMOTE CONTROL HIGH QUALITY THROUGH PLATED P.C.B. ALL I.C. MOUNTED ON SOCKETS PREALIGNED UHF/IF MODULES NEEDS NO INTERNAL CONNECTION TO THE TELEVISION SET SIZE 430mm x 90mm x 220mm SUPPLY 240v 50Hz 35w NEW *TOUCH CONTROL KEYPAD* NEW

INCLUDES TUNER, P.S.U., DECODER, REMOTE KEYBOARD, P.A.L. ENCODER, U.H.FMODULATOR CASE WITH SCREENED AND PUNCHED FRONT PANEL.

- £189.90 inc VAT. P Et P £3.00

FULL TELETEXT MANUAL IF BOUGHT SEPARATELY - £2.50 P Et P £0.50.P.C.B' S AND L.S.I. I.C' S NOT SOLD SEPARATE FROM KITS. P Et P INCLUDES CARRIAGE, PACKING AND INSURANCE

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ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 85

DEEP SPACEPROBESThis month Ian Graham tracks down the interplanetarysuperstars - Viking, Voyager and Pioneer.

UItil recently unmanned spaceflights have beenovershadowed by the glamour of manned missions,especially the Apollo series However, in the nitpat

between the last Apollo flight in December 197.2Ahird tobelieve it's almost seven years agoi anti tht I awaitedre -useable shuttle unmanned space probes, come intotheir own

In the foreseeable future men areMars. so any on -the -spot study of ti

probes. Our first do,of another world came from the,'

ly to visit onlynets must be done

p view of the surfacelet Luna -9 in January

1966 Since then, spacecraf aye crashed into, softlanded on or flown by Mercury, Venus, Mars, Jupiter andSaturn. Soviet motorised 'wheelbarrows' have even trund-led across the Moon's surface, picked up rocks andreturned them to Earth

The recent stars of stag?, screen and now ETI are Viking,Voyager and Pioneer, Although the Mariner spacecraft sent

The Viking spacecraft weighs over three tons and consists of anOrbiter and Lander (here shown encapsulated in its bioshield).When the Lander is sitting on the surface of Mars, it radios databack to earth via an aerial On one of the Orbiter's four solar panels.

impressive photographs of Mars. Viking made theeadlines Viking was special, because it was sent to look

for evidence of life on Mars, the most Earth -like planet inthe Solar System In addition, it would study theatmosphere and geology of the whole planet. Each of thetwo Vikings launched in 1975 was a double spacecraft.While the Orbiter circled Mars. photographing the surfaceand studying the atmosphere, the Lander carried itspayload of instruments down to the surface.

The Lander. although less than ten feet across, con-tained the equivalent of two power stations, two computercentres, a TV studio, a weather station, two chemical labs,three -incubators, a scoop and hoe to dig trenches andcollect soil samples. an Earthquake i:Marsquake') detectorand miniature railway wagons to deliver the samples to thelabs and incubators.

Landing Snaps

Viking -1 orbited Mars for a month while the Orbiter carriedout a detailed photographic reconnaissance of the pro-posed landing sites. Apparently smooth sites, photo-graphed by Mariner -9 showed up as cratered. rockyspacecraft killers under Viking's cameras. Finally. theLander was committed to a landing at a site in the Plains ofChryse. A month later, Viking -2 came iiiown to a suc-cessful touchdown in the Plain of Utopia.

The two sites were found to be quite different in natureChryse featured exposed bedrock, a large variety of rocktypes and sand dunes. Utopia featured more abundant,more uniform, generally vesicular rorl<, but no sanddunes.

Viking -1 was not the first spacecraft to stand on theMartian surface. As in so many space activities, the SovietUnion did it first, but did not follow up its lead. Mars -3successfully soft -landed in 1971, but stopped sendingback data after only 20 seconds

The most striking feature of the first photos receivedfrom Viking was the colour of the Martian landscape andsky. The first colour pictures showed a pink sky Asscientists had expected to see a blue sky, a few knobs onEarth were twiddled to make the sky blue. However, we

now know that Mars hathe red surface dust bstrong winds.

Even thouhundredth ofound severeOn one day in 19reached their maximualthough the terre150' F higher thatemperature ranges fin the middle oover the Plains aGreat Plains of int

Although theAter content of

d on the Rospheric watwhite fog inever, in the

4k sky, used b

rried i o thka

4k

t rth tikpthe

e atmosemperatures

axiNtrn tempe

k ,,Theafter

s thate, Vikplanpia

local tie was so

y fy(aawn to

e wind behavioublowing over the

ly a thousandth theand fog are to be

and deep in craters,old night, appearingIt vaporises again,

mt4sph-ri essure about 8 milli -n clirribs high in the sky

eterological feature notous seasonal variation in .atrnOsp eric pr

nrforith, the Viking Lander recorded a d

0.03%be that, in winter, carbon oxide, whatmosphere

out onto the southerThe second most commo

the Martian soil, silicon beinHowever, only a small fractimagnetic, suggesting that th e must bemineral of iron, not all of whic are magnetic fn general,the soil was similar to terrestrial and Lunar basalt lava.Weathering and contact with the water -rich atmospheremake it more Earth -like than the dry, urfiiirrtinfic red Lunarsoil

Look Lively

1111.11M

de

ronled tt prekoke

rgane soil

esultra actifor pact"the 1

terato

aid, in.il, but" `S

unest4a1verlb

rho

M

.m0

s to ioe yvh yo

rth some forhere on the plans provided-It-after org

any chemicalioactive carbon dioxide atctive compounds produced byanother experiment, the gas aboanalysed for anything which might

I activity. A third experiment addedto the soil, while instruments look

bon dioxide exhaled by any organism

th is anure. In51 It

s 'Ofb),

ents,eri-

re;

ng several samples in each Lander'sresults are inconclusive. The experiments

cord some form of chemical activity in theclear if this was due to living organisms or

ernical make-up of the soil itself. Despite thes from these experiments, no trace of thees that make up terrestrial living organisms

were he depth of analysis necessary to find out,.what is going on in the Martian soil is beyond the capa

S band high gainantenna (Lander to

DSN direct link)

Magnifying mirror

Radar altimeterelectronics number 1

Seismometer

Radioisotope thermoelectricgenerator power source

(under Cover) (2)

Ultrahigh frequencyantenna (relay)

Magnet and cameratest target

Roll engine 141

S band low gainantenna

Terminal descentpropellant tank (2)

Terminal descent landingradar (underside ofLander structure)

Leg 3

Radioisotope th rmoelectricgenerator co

Prupu

View

Xxray,flunresconce

mirror 121

Radar altimeter antenna

ant "es INOnfunctioning inf, and larded configuration)

keup lines

Radioisotope thernioeiectricgeneratcr wind cover 12)

121 Meteorology sensors

Terminal r scentengine 31

118 nozzle con rquration)

Ternperatnre sensor

Leg 2

Gas chrornalograph massspectrometer processor

Biology processor

Forlable boom

Collector head

Fig. 1. The Viking Lander is laan tic I tberatory designed tomastudy the structure, surface and atmosphere it Mats and to took forlife forms.

ities of Viking, so the question of life on Mars is unlikely tobe resolved until samples can be returned to Earth by anautomatic probe or until man lands on t le planet. Althoughthe latter is tech ally possible, there remains theof the so -far un wn effects of deep space missions on thehuman body 11, 'by no means clear yet whether mannedspaceflights as we know them today, but lasting severalyears, are passible. IP,

This artist's impression shows the Viking Lander heading fortouchdown after a year in space. The aeroshe I is descending on a

rachute in the distance.

10 EUROPA

GANYMEDE CALLISTO

In Marc is 1979. Voyager -1 took these photographs of the four farge-Glilean satellites of Jupiter. Garinymede and Cellist° are biggerthin Mercury. lo and Europa are about the same sire es Earth'sMoon. The reflectivity of the satellites varies according tonature of their surfaces. in may be covered with sulphur and(63M., reflectivity), Europa with water ice (46 Gann 3d1;

ice and rock (43%) and Cellist° with rock -covered iceThe interiors of the satellites showed similar dive

Et_rope have rocky in 3, Maina kit of water or ice

-v,...,ht/ef-1 this photograph while still 20 mi lies from;

Avner. Bright cloud in the equational region north o Great RedSpot appears to be where bright couds originate from, then licivevrestwead. However, t ght ovals south of the Great Red Spotappeared about 40 y go an.$ have remained relatively tnr.

aged ever since.

on thehed after

upiter, to arriveft receded fromtook ten hours to

ree days). Voyager -1d video systems, capt

ary Moon in one pictus away;,the first time it

them, the two Voyagthe atmosphere and

d Saturn and survey in desaisellits.At 60 million ki,

clit's,,,iaritow angle cameu tre '130 dais untilngle and then'the widof colour pnoi,ogr,a,p.hs oe narrow angle camerafeatures, like the Greatlight photography, u

is observations wereon the structure andonomy experimentthe planet's surfa

phere and brilli.on.

e Viking

IMAGING, NA

WA

PLASMA

COSMIC RAY

HIGH -GAINANTENNA(3.7-. DIA)

HIGH -FIELDMAGNETOMETER

SPECTROMETER

INFRAREDSPECTROMETERAND RADIOMETER

PHOTOPOLAR (METER

?I'ZiGNE4RXTICLE

MICROMETEORITESHIELD 51

OPTICAL74\T CALIBRATIONTARGET ANDRADIATOR

PLANETARY RADIOASTRONOMY ANDPLASMA WAVEANTENNA (21

GENERATOR (31

LOW -FIELDMAGNETOMETER(21

(SPACECRAFT SHOWN WITHOUTTHERMAL BLANKETS FOR CLARITY!

Biro tly VOyatures, whir

1 origin Taskingerial for

r- from half a milFon mites, shoro1SDe maul< rite mpact craters

teguisr pabches seem toTho surface is thought

FAAGNITOmE TEROPT)

IMAGING PNOTOPOLARIARE TERDIFFUSER

NLITATION DA

MAGNETOMETER 100. SUPPORT

HIGH -GAIN ANTENNA REFLECTOR

TRAPPED RADIATION °incur,'(1.550)

PLASMA ANALYZER (MC)

aV/PRECESSIONTHRUSTER ASSEMBLY

GEIGER TELESCOPE (U. OF IOWA)

IMAGING PHOTOPOLARImE TER(U. OF ARIZONA)

SRIN/DESPIN 'NEWER ASSEMBLY

Uv MOT CH.AE IER ( C)

LOW -GAIN(OMNI) ANTENNA

MEDIUM -GAIN ANTENNA COSMIC /AY TELESCOPE (GSFC)

HIGH -GAIN ANTENNATEED ASSEMBLY

SEPARATION SING

THERMAL CONTROLLOUVER ASSEMBLY

CHARGED PARTICLE INSTRUMENT(U. OF CHICAGO)

041E00010 DETECTORSENSOR PANEL (12)

(ANGLEY RESEARCH CENTER)

AVAMECESSION ',MUSTER ASSEMBLY

SUN SENSOR

STELLAR REFERENCE ASSEMBLYLIGHT SHIELD

ASTEROID-MBTIOROIDDETECTOR SENSOR (G E.)

Fig. 3. The Pioneer spacecraft. Power is derived front four Radio-isotope Thermal Generators (Ries). Pioneers -10 and 11 were eachlaunched by an Atlas Centaur vehicle fitted with a solid fuel thirdstage. Launch from the Cape was on a direct ascent trajectory. Atthird stage cut-off the Pioneers had a velocity of about 32,4the fastest a man-made object had ever travelled in space.

Fig. 4. Each Pioneer spacecraft carried one ofthese plaques on its way to the outer planets.The diagram should show scientificallyeducated inhabitants of another solar system, Awho might intercept the spacecraft millions ofyears from now, when Pioneer was launched, o 0, 0 0 0from where and by what kind of beings.

11G

FEATURE: Dee Space Probes

trig passed Jupiter, Voyager -l's work isn't finished yetwill carry on to encounter Saturn at the end of August;81. Although Voyager -2 was launched 16 days beforager-1, it will not reach Jupiter until June 1981. 1

ntrast with Voyager -1's mission, which was caref..'preplanned. Voyager -2's flight -plan has been delib Myleft very flexible to respond to the progess and

.

received from Voyager -1. If Voyager -1's Saturn fly -byaccording to plan, Voyager -2 may be sent out to encounteUranus in 1936, using Saturn's gravity to help it on itsway

A'. such huge distances from the Sun solar panelscannot be used to produce power. Instr.ad, the twinVoyagers carried their own Radioisotope Thermal Genera-tors (RTGs), generating 1800 watts of heat, which wasconverted by thermocouples into 400 watts of useableelectric power

The Voyager e first spa aft to fly byp:tier Five "ioneer raft photo -

`ant *trey de'. gain this,y appro ched the rim

1 1 , la nched in 1 anri 2.74 m di meter hig

c to Earth. Small hydraz' ee h are used to keep p

ourse adjustments anft. El ical power I

launched inr, a cosm'charged ler, an }r p

minorspacec

Pionagnetomediometer,

ra iation detetelescope, alyser, metermeteoroid dthe a

1

CIO r sera

er Sitste

aunched..fromope

les th

nets Inr Tat;'

s put co79. T e scie

princi f consecreat or destroys

ra s, ationai, field to aceing lose energy

After sirn, pa

ps andplanet. Itopposite

Whathas a mmagneticatthe E

ears ined only 1

ve us thnow h

ection tPione

netic f -I.field at t eh's sur c

in adda

s sacecrPione0 km

ever c.out

eer 1rn fin

nd trud toyet S

tr usin

djrOV

t, Satighs 2a rial to

rsundcts Earth

n rater RTG,.eliiirii ye

vere itn itsar

11ter, itmber

th theat he

war'sone -of the er-

t loses energy? -sive that the loss in

s gain is impprceptible.1 1 , now called Pioneer

rom the Saturnian cloudse -up photographs of thethe Solar System in the

? It discovered that Saturnped radiation belts. The

is slightly weaker than thatrn is almost 100 times as

4110 OINWOMMAISII. Ma

Saturn took these photographs of Saturn only hours beforet approach. The imaging photopolarimeter gathers data using

red and blue components of reflected light frorr the planet. Thecomponent is shown top and red above.

massive as Earth Saturn was also fo.ind .o have a hotinterior. Pioneer came close enough to the alanet to passthrough the outermost E -ring and, -in doing so, discoverednew rings. I hroughoutthe iasiOn Pior eer waS,tracked byNASA's Deep Space in CalifOrni9, Spain andAbstralia. The 10,000 commands sent t6 the spacecraft inthe for <ight before closest approackepch took 85 minutes

there Godd communications are expected to con -into th :1,1(1-1980s

as BallSaturn's core of molten heavy elements seems to oe aboutthe same size as the Earth, but three times more massive.Hot liquid methane, ammonia and water surround the core,but most of the planet is composed of very fight gases -hydrogen and helium. In the intense pressure of the lowergas levels, the hydrogen is in a liquid metal state. Abovethis, there is a layer of liquid molecular hydrogen Er1

I would like to express my thanks to the folowing fortheir assistance in the preparation of 'his article.Jet Propulsion Laboratories, California.Ames Research Centre, California.NASA, Washington.

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STEREO PRE -AMPLIFIER POWER AMPLIFIER POWER SUPPLIESWe produce suitable power supplies which use our superb TOROIDAL transformers only 50rnrn high with a120-240 primary and single bolt fixing (includes capacitors/ bridge rectifier)

CPR 1 - THE ADVANCED PRE -AMPLIFIER. The best pre -amplifier in the U.K. Thesuperiority of the CPR 1 is probably the disc stage The overload margin is a superb 40dB, thistogether with the high stewing rate ensures clean top, even with high output cartridgestracking heavily modulated records Common -mode distortion is eliminated by an unusualdesign R I AA is accurate to 1 d8 signal to noise ratio is 70dB relative to 3.5mV. tistooion

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4iika4.0 POWER AMPLIFIER KITThe kit includes all metalwork heatsinks and hardware to house any two of our power amp modules plus a powersupply. It is contemporarily styled and its quality is consistent with that of our other products Comprehensiveinstructions and full back-up service enables a novice to build it with confidence in a few hours.

PRE -AMPLIFIER KITTHIS INCLUDES ALL METAL WORK. POTS. KNOBS. ETC - TO MAKE A COMPLETE PRE -AMP WITH CPR 11S1MODULE AND THE MC112) IF REQUIRED.

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F E T muting No controls are fitted There is no provision for tone controls. CPR 1 size is138x 80x 20mm Supply to be ± 15 volts.

MC 1 - PRE -PRE -AMPLIFIER. Suitable for nearly all moving -coil cartridges. Sensitivity70 1 70uV switchable on the pc b This module brings signals from the now popular lowoutput moving -coil cartridges up to 3 5mV (typical signal required by most pre -amp discinputs) Can be powered from a 9V battery or from our REG 1 regulator board.

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POWER AMPLIFIERS. It would be pointless to list in so small a space the number ofrecording studios. educational and government establishments, etc., who have been usingCRIMSON amps satisfactorily for quite some time. We have a reputation for the highest qualityat the lowest prices. The power amp is available in five types, they all have the samespecification T H D typically 01% any power 1kHz 8 ohms. T.1 D insignificant, slew ratelimit 25V uS. signal to noise ratio 110dB. frequency response 101-1z35kHz - 3dB stabilityunconditional, protection drives any load safely- sensitivity 775mV (250mV or 100mV onrequest) sire 120 x 80 x 25mm

POWER SUPPLIES. We produce suitable power supplies which use our superb TOROIDALtransformers only 50mm high with a 120-240 primary and single bolt fixing (includesLapacitors hridge rectifier)

POWER AMPLIFIER MODULESCE 608 60W/8 ohms 35-0 35vCE 1004 100W/4 ohms 35-0.35vCE 1008 100VV/8 ohms 45-0-45vCE 1704 170W/4 ohms 45-0-45yCE 1708 I 70W/8 ohms 60-0-60v

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TOROIDAL POWER SUPPLIESCPS1 for 2xCE 608 or TxCE 1004 .E18.56CPS2 for 2xCE 1004 or 2/ 4xCE 608 £18.80CPS3 for 2xCE 1008 or 1xCE 1704 E19.75CPS4 for 1xCE 1008 E17.12CPS5 1 for 1xCE 1708 E24.15CPS6rnk 2xCE 1704 or 2oCE 1708 E25.53

HEATSINKSLight duty. 50mm. 2 C/W £1.44Medium power. I 0Ornm. I -4 -C/W E2.35Chaco/group. 150mm, 1-1-C /W E3.04Fan, 80mrn, state 120 or 240v E19.70Fan mounted on two drilled 100mm heatsinks2s4 C/W, 65 mas with two 170Wmodules

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CPR1 01.65CPRIS E40.87MC1 £21.28MC1S E33.17Pre -amp Kit E38.07

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Badger Sound Services Ltd., 48 Wood Street. Lytham Sr Annes. Lancashire F58 1QG

All prices shown are UK only and include VAT and post. COD 90p extra. E100 limit. Expos is no problem. pleasewrite for specific quote. Send large SAE or 3 International Reply Coupons for detailed information.

92 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

ELECTRWRCATALOGUE

10Ready early December

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ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 93

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94 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

FEATURE

LOUDSPEAKERDESIGN PROPOSALFollowing up his Audiophile contribution, H. Lipschutz is backagain with an ingenious method of increasing both efficiencyand bass linearity.

In my first article Audiophile) about the need to improvespeakers, I showed that three areas of improvementexisted, and concentrated on the first: - reduction in

size, showing how this could be achieved without loss ofquality or bass response. At the end of the article I thenmentioned a patent which dealt with the second area ofimprovement, namely efficiency.

In the meantime the complete patent has been appliedfor, and in this article I will now show how to go about thereduction of size and increase efficiency (at least ten fold)!But before talking about the solution, let's first consider theproblem. This is that at low frequencies the travel requiredof the diaphragm has to be much further than at higherfrequencies. This can easily be seen when looking at agramophone record groove, where the bass frequencydominates the groove spacing, and can easily be recog-nized. Now a cone in free air, when driven with a bass note,would automatically take up the distance required. Whenthe speaker is mounted in a sealed enclosure however, theair behind the cone gets compressed every time the conemoves inwards.

Efficiently Up!The enclosed air resists that movement and tries toreturn the cone to centre. Reducing the size of the box hasthe same effect as changing a petrol engine into a very highcompression diesel, i.e. a much bigger starter motor is nowrequired to turn the engine over. Similarly, with thespeaker, we need 1 2 dB more power per octave from theamplifier, - not for playing louder, but only for compres-sing and rarefying the enclosed air, and heating it up.

Obviously it is a great waste of good amplifier sound touse it for just that. Previously I have showed that by raisingthe acoustical efficiency of the speaker, it is possible tomanage with normal amplifier powers as used with con-ventional bass speakers, and still reduce the size of the box.However, the difference of 1 2 dB/ oct is still there, and I

can produce all the bass needed with, say, 40W. Withoutthe hindrance of the enclosed air, however, the same basslevel could be produced with 3W!

It would be nice if that could be done. Well, it can be,that is what this patent is all about.

For every position of the cone there is a correspondingcompression or rarefaction of the enclosed air, which actsas a restoring or excess centring force. Ther force needed toovercome this is the same for every cycle, and is therefore

Fig 1. The first version of the speaker design with a common magnetbut which uses individual Air Flux Gaps. The letters mark thebeginning and end of the windings. Audio is present on coil AF andcoils DC carry the centering current. The numers stand for: (1)Speaker chassis: (2) Diaphragm: (3) Roll surround: (4) Suspensionor spider: (5) Magnet: (6)a Voice Coil air gagp: (6b) Balancing coilair gap: (7) Coil Former: (8) Voice coil: (9) Balancing coils.predictable. It can therefore be overcome by a force actingin the opposite direction, and by so balancing it cancelled.

Thus, all that is necessary is to add two more coils, i.e.one to each end of the voice coil, and connect these two'balancing coils' to a DC supply. When the Cone now ismoved off-centre by the voice coil, the balancing coil at oneend moves closer towards and into the magnetic flux gap,which then produces a force pulling it further, and assistingthe voice coil to overcome the excess centering force of the*

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 95

enclosed air. Naturally the balancing coils have to bewound with suitable shape, and the DC supply has to beadjusted so that the force produced is just enough toovercome the resistance of the enclosed air to the move-ment of the cone. If too much DC is applied, then the conewould tend to be unstable and possibly move on its own,and with not enough DC we would be back to square one,and most of the work would have to be done by the voicecoil, i.e. the amplifier, and bass would be lost unlessespecially boosted.

By adjustment of the DC supply therefore, the balancingforces can be adjusted to compensate for just the rightproportion of work to be done, and thereby relieve theamplifier of this pump load represented by the enclosed air.Furthermore, by the simple expedient of limiting the lengthof the balancing coils, their effectiveness is limited tonormal excursions of the cone, thereby preventing excess-ive swing.

16

17 8 - .11 18

14 -

D C

15

///// /1/////11

17A

13

10

12

AF

Fig 2. A version of the design which uses an independent fluxbalancing system. Key:- (10) Coil former: (11) Diaphragm: (12)Voice coil magnet: (13) Voice coil: (14) Balance coil magnets: (15)Chassis: (16) Spider frame: (17) Balancing coils: (18) Air gap.

Brake To A St opPractically every modern car has servo -assisted brakes, andthis is taken for granted. I therefore see no reason why notto apply the same sort of solution to bass speaker workload. There is no difficulty in supplying DC, which, for carspeakers, can be taken from the car battery without trouble,and from rectified mains for home equipment. The altern-ative is and remains the solution indicated in my firstarticle, or the conventional approach of the big box, with

Fig 3. Here the balancing coils and the audio carrying voice coilsshare a common air gap and magnet system. The dotted linerepresents the point about which the centering force acts. (19)Voice coil (20) Balancing coils.

walls that are difficult to prevent from vibrating and therebycolouring the sound, and paying for the woodwork androom space required. But in the mobile field, there really isno choice.

DC For Dead Centre?Remains the last area of improvement, - quality ofreproduction. That too can be improved, with designswhich retain small size and high efficiency, and solutionsare known to me. But I would have to find more supportbefore going for more patents. These cost money and causea lot of work, and are wasted unless something is done withthem. I am sure the market for improved speakers exist, butwho will fill the demand remains to be seen. I am adesigner, and I like solving problems; but I am not aproducer with a company supplying the market. It is up tothose to make the next step.

However, even in the version just described there is animprovement in quality too, due to the fact that when aproportion of the centering force is cancelled, any non -linearity of the suspension is cancelled as well, resulting ina lowering of distortion.

96 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

FEATURE: Loudspeaker Design

Fig 4. A much simplified and improved version with utilisingvirtually a standard loudspeaker chassis, but where the coil is muchmuch longer and carries both DC and AF signals.

In Summary

A transducer with (Jectro-magnetically extended bassresponse, with a vibratory diaphragm, incorporating ad-justable means to oppose the centering force exerted uponthe said diaphragm by the enclosed air of the transducer'ssealed enclosure, said means comprising a magnet assem-bly defining a gap across which a magnetic flux extends toform a magnetic field, two coils secured to said diaphragmand movable axially in said gap, said coils' operative lengthlimited to the designed travel distance of said diaphragm,and a DC supply for said coils, adjustable for balancing theair stiffness of differently sized enclosures, and lowering of'main system resonance' to that exhibited by conventional,normally much larger enclosures.

Howzat? ET1

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ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 97

40014002400740094011401240134015401640174018

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A SELECTION' LM318N 75pLM324 45p

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NE531 980NE555 .23pNE556 60pNE567 100pRC4136 100pSN76477 230PTB A800 70PTBA810S 100PTDA1022 620pTL081 45pTL084 125pZN414 80pZN425E 390pZN1034E 200p

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OPTO

LED's 0.125.n.0.2inRed TI L209Green T I L211Yellow T I L213Clips 3p

DISPLAYSDL704 0.3 .n CCDL707 0.3 in CAEND500 0.5 in CC

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TRossitmsAC127AC128AC176AD161AD162BC107BC108BC108CBC109BC109CBC147BC148BC177BC178BC179BC182BC182LBC184BC184LBC212BC212LBC214BC214LBC477BC478BC548BCY70BCY 71

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Low profileby Texas

8pin So 18pin 14p 24pin14pin 10p 20p.n 16p 28pin16pin lip 22pin 17p 40pin3 lead T018 or TO5 socket. 10p eachSoldercon pins: 100' 50p 1000370p

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VEROBOARDSize in. 0.1 in. 0.15.n. Vero25 x 1 14p - Cutter 80p2.5 x 3.75 45p 45p2.5 x 5 54p 54p Pin insertion3.75 x 5 64p 64p tool 108p3.75 x 17 205p 185PSingle sidedpins per 100 400 40PTop quality fibre glass copper board. Singlesided. Size 203 x 95mm. 60p each.'Dalo' pens. 75p each.Faun rr, xeff shePtc of Alfac. 145p per pack.

RESISTORSCarbon film resist-ors. High stability,low noise 5%.

E12 series 4.7 ohms to 10M. Any mix:each 100+ 1000+

0.25W 1p 0.9p 0.8p0.5W 1.5p 1.2p 1pSpecial development packs consisting of10 of each value from 4.7 ohms to 1 Meg -ohm (650 res) 0.5W £7.50. 0.25W E5.70.METAL FILM RESISTORSVery high stability, low noise rated at '4W1%. Available from 51onms to 330k inE24 series. Any mix:

each 100+ 1000+0.25W 4p 3.5p 3.2p

LINEAR

Z 1 X b002N6972N30532N30542N30552N34422N37022N37032N37042N37052N37062N37072N37082N38192N38202N39042N39052N39062N40582N54572N54592N5777

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MYLAR FILM0.001, 0.01. 0.022, 0.033, 0.047 3p0.068, 0.1 4p

POLYESTERMullard C280 series0.01, 0.015, 0.022, 0.033, 0.047, 0.068, 0.1. 5p0.15, 0.22 7p0.33, 0 47 10p0.68 14p1 OuF 17p

CERAMICPlate type 50V. Available in E12 series from22pF to 1000pF and E6 series from 1500pF to0.047uF 2p

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A MERRY CHRISTMASAND A

HAPPY NEW YEAR

CONNECTORS

JACK PLUGS AND SOCKETSscreened unscreened

2.5mm 9p 13p3.5mm 9p 14pStandard 16p 30pStereo 23p 36p

DIN PLUGS AND SOCKETSplug chassis

socket2pin 7p 7p3pin 11p 9PSpin 180° 11p 10pSpin 240° 13p 10p

1mm PLUGS AND SOCKETSSuitable for low voltage circuits, Red & *lack.Plugs: 6p each Sockets: 7p each.

4mm PLUGS AND SOCKETSAvailable in blue, black, green, brown, red, whiteand yellow. Plugs: 11 p each Sockets: 12p each

PHONO PLUGS AND SOCKETSInsulated plug in red or black . . 9pScreened plug 13pSingle socket . . 7p Double socket 10p

socket7p8p

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linesocket

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STEVENSONElectronic ComponentsCHRISTMAS SPECIALSA range of special offer items validduring December. All orders placed'for these items must be receivedduring December.

Murata Ultrasonic Transducers, per pair

PCB etch kit. Contents:5 assorted sheets Alfac. Pound of FerricChloride. Da'o pen. Fibre glass PCB.

Resistor Development Pack.10 off, each Y4W value from 4.70 to 1M -Pep 470p

Polyester Development Pack.5 off, each value from 0.01uF to 2u2. -6-20p 480p

Texas sockets. Must be in multiples of 100.8 pin, per 100 750p

14 pin, per 100 900p16 pin, per 100 1000p

Pack of 10 x NE555 -20013- 200p

Pack of 10 x PP3 clips -40p 45pPack of 10 crocodile leads (20 clips) -1-4-5p" 90pPack of 6 x C10613 thyristors -2-70r5 220p

Pack of 70 x 1N4148 -148P. 100p

Expo Reliant drillExpo Titan drillLEDs, Pack of 10 x 0.2 Red

10 x 0.2 Green10 x 0.2 Yellow

AY51013P UART2114 Low Power 300nS2708 EPROMSS -2 Breadboards

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PANEL METERSHigh quality 2" wide view meters.Zero adjustment. Back illuminationwiring.Available in 50 uA, 100 uA, 500 uA,1 mA, 100 mA, 500 mA, 1A. £4.75 ea.VU meter similar style. £1.40 ea.

SLIDE POTENTIOMETERSGood quality 60mmtravel slider with80mm fixing centres.Available from 5k - 500Kin log and linear. 55p each.Suitable black knobs 6p ea. Coloured knobs 10p ea.

We now offer one of the widest ranges of components atthe most ccmpetitive prices in the U.K. See catalogue forfull details. We welcome callers at our shop in College Rd,Bromley, from Mon -Sat, 9am-6pm (8pm on Weds andFridays). Special offers always available.We also provide an express telephone order service.Orders received before 5pm are shipped same day.Contact our sales office now with your requirements.TELEPHONE: 01-464 2951/5770.

Quantity discounts on any mix TTL, CMOS,74LS and Linear circuits: 100+ 10%, 1000+15%. Prices VAT inclusive. Please add 30p forcarriage. All prices valid to April 1980.Official orders welcome.

aik1. PISA BARCLAYCARD

& ACCESS WELCOME.

Mail orders to: STEVENSON (Dept ET)

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1980 Electronics Catalogue nowavailable price 75p + 20p postage. Ifyou send £1.55 you will receive ourCatalogue plus six bi-monthly Short -

form Catalogues to keep you up todate with prices and special offers.

HOME COMPUTING BARGAINS BATTERY ELIMINATORSFull keyboard. cemette interface. use your tv as a vdu 3 -way types with switched output and 4 wayOhio Scientific Superboard II fully assembled. 8K multi -lack 3/4 V7 ' 6v 100ma [2.39. 6 / 71/2 /9Vbase 4K ram, special offer price now includes free 300ma £3.14. 100ma radio types with press studpower supply and modulator kit El 88 + 1596 VAT conic tors 9v £3.57, 6v E3.57, 41/2v 63.57, 9 +9cTandy TRS80 level 2 basic. 16K ram. includes E4.79, 6+6v £4.79. 41/2 + 4'hy £4.79. cassettemodulator and psu £450 + 15% VAT recorder mains unit 71/2v 10Orne with 5 pin din plug

£3.57. Fully stabtlialed type 3/6/71/2 /9,v 400maSINCLAIR PRODUCTS £5.76. Car convertors 12v dc input. output 9vPFM200 E51.95, case E3.40, adaptor £3.40, 300rns E1.19. output l'hy 300ma E1.19, outputconnector kit L11.27. M,crovision TV E91.44. 3/41/2/6/ Ph /9/ 12v BOOrna E2.1111.mains adaptor E8.88. PDM 35 E29.79, mainsadaptor £3.40, case £3.40. DM350 E71.52.DM450 £102.17. DM235 £51.95. Accessories for BATTERY ELIMINATOR KITSall 3 models rechargeable bananas £7.99. mains 100rna radio types with press -stud connectors 41/2vadaptor /charger 63.94, case 68.90. Enterprlse prog £1.49, 5v £1.49, 9v £1.49, 4'h +41/2v £1.92,calculator E22.115. New SC110 10MH: oscilloscope 6+6v E1.92, 9+9v E1.92. Cassette type 71/2v£144.95. 100ma with din plus £1.49. Heavy duty 13 way

types41/2/6/7/81/2/11/13/14:1//21/26/28 /COMPUTER GAMES 34/42v 1A E4.95, 2A 0.72. Car convertor inputChess champion 6 £49.95. Chess challenger 7 £94. 12v dc, output 6/71/2/9v IA subdued £1.35.Voice chess challenger £227.95. Checker challenge2 MI. Checker challenger 4 CU. Star chess 02.rGrandstand video entertainment computer E79.95. STABILIZED POWER KITSVideocarts £12.50. Philips G7000 Video pak The last price is for kit without transformer. thehome computer E149. Videopaks £12.95. Atari brackmad_ pAe/ingcliid2es, itrahsfor me, 8 -way types

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Variable voltage models 2.18v 100rna £2.12TV GAMES (E2.99). 130s 1 A £2.99(£5.951, 1-30v 2A £4.95Tank bathes kit £7.34. AV -3-8500 chip £5.27, kit (E11.24).E4.25. Stunt cycle AY -3-8760 chip E13.83, kit£4.00. 10 game paddle 1 AY -38600 chip £10.25, BI-PAK AUDIO MODULEShim £7.03. Racing car chip AY -3.8603 £13.53. AL304 £4.08. PA17 1E8.38. PS12 E1.58. T538Modified shoot kit £5.25. Rifle kit £5.27. Colour £2.70. 5450 £25.08. AL60 £5.08. PA100generator kit 01.05. Joystick 2205 £1 .80. £17.33. SPM80 E4.74. BMT E5.08. Stereo 30MAINS TRANSFORMERS £21.57. MA60 £35.72.

6.06V100ma 7119. 11/28E2.90. 9.0.9V 75ma 75p,la (2.22, 2a E2.89. 12-0-12V 100ma 92p, 1a COMPONENTS£2.75, 15-615V la £3.09. 1N4148 0.9p. 154002 3.1p. 741 8 dil 1Sp. 723

14 MI 31p. NE555 8 dot 25p. bc183, bc213.JCI2 AND JC20 AMPLIFIERS Le547. bc549 4.2p. bc182, be 184. bc212. 66214,Integrated circuit audio ampl der chips with data and 1.548 SP. 03lo. bp32r 30e. oo416 39p. bd131,printed circuits JC 12 6 watts £2.08. JC20 10 warts OO1322 /p. Plastic equty bc107 5p. Fuses 20mm

x£3.14. Stem cartridge 15. 25, 5 1 2, 3, 5 amp

quickblow 1p. anti -surge 3.6p. Resistors 5% 'AWCONTINENTAL SPECIALITIES PRODUCTS E12 106 to 10M 1p, 0.3p for 50+ of one valueEXP300 £5.51. E0P350 E3.92. EXP325 £1.54. Polyester capacitors 250v 0 15, 0 68. I mf 1.5p.EXP650 £4.14. ESP48 E2.64. LP2 £20.70. 01, 033. 33 2.8p, 022 047mf 3.3p, 22, 47mf

4.99, polystyrene capacitors E 12 63v 10to 1000 ofPRINTED CIRCUIT MATERIALS 3p 1n2 to 10n 4p. ceramic capacitors 50V E6 pf toPC etching kits economy £2.32, standard E4.35. 47n1 2p. Electrolytic capacitors 50si 5, 1. 2mf 8p,40 sq ins pcb 68p. 1 lb FeCI £1.30. etch resist pens 25v 5. lOmf Sp, 16v 22, 33mf Sp, 47. 68mf 3.5p,economy SOp, delo 84p. drill bits 1/32" or lmrn 100mf 99.330 470m1 9p, 1000rnf 10p. Zeners27p. Etching dish 89p. Laminate cutter 82p. 400r6W E24 2u7 to 33v 7p. Preset pots submtnta

ture 0 1W hone or vent 100 to 4M7 6p. PatenS-DECS AND T-DECS borneters 'AW 457 to 2M2 log or lin single 27p, dualS -Dec £3.79. T -DEC £4.59. u-DECA £4.69. u -Dana 57p. 'Al" red LEDs 9.7p. IC sockets 8 di111.7p, 14 dii£7.18. 12 dt1 adaptor £2.31. 10.19, 16 6112p.

SWANLEY ELECTRONICSDEPT ET!. 32 Goldsel Rd., Swanley, Kent BR 8 8E2.

Mail order only. Please add 30p to the total coat of your order for postage. Prices include VATunless stated. Lists 24.p post free. Oy ustomars deduct 13%. Official credit orderswelcome.

7400 12p 7476 35p 74160 90p 4013 50p LINEAR LM348N 90p SAS660 270p TBA810TBA820

1043p80p7401 12p 7480 50p 74161 100p 4015 80p CA3039 70p LM 380 80p SAS670 250p

T8A920G 290p7402 12p 7481 85p 74162 100p 4016 45p CA3046 70p LM381N 150p 51_917B 650p7CA270S 250p7403 12p 7482 75p 74163 100p 4017 80p CA3060 225p LM382 120p SN76666N 100p

7404 12p 7483 80p 74164 115p 4018 80p CA3065 200p LM391 170p SN76003N 170p TCA270QTCA760

250p300p7405 18p 7484 100p 74165 120p 4019 50p CA3076 250p LM555 25p SN76013N 150p

TCA4500A 300p7406 30p 7485 75p 74166 140p 4020 100p CA3080 75p LM 565 125p SN76013ND 130pTDA1004 300p7407 35p 7486 35p 74167 200p 4022 95p CA3084 250p LM709C 40p SN 76023N 150pTDA1008 320p7408 18p 7489 200p 74170 200p 4023 25p CA3085 gor LM 710705 65p SN76023ND 130pTDA1022 600p7409 18p 7490 35p 74173 120p 4024 55p CA3086 50p LM710DIL 65p SN 76033N 180pTDA1024 125p7410

741112p20p.

74917492

80p40p

7417474175

90p90p

40254026

20p150p

CA3088CA3089

185p225p

LM 723705 40pLM723DIL 40p

SN76131N 115pSN76227N 150p TDA1034

TDA2002250p320p7412 18p 7493 35p 74176 85p 4027 50p CA3090AQ 400p LM 733 120p SN 76228N 160p

TDA2020 320p7413 30p 7494 85p 74177 80p 4028 85p CA3123E 200p LM 739 150p SN76660N 85pTL081 50p7414 50p 7495 70p 74178 160p 4029 100p CA3130 100p LM 741 20p TAA300 250pTL082 100p7416 30p 7496 60p 74179 140p 4030 60p CA3140 70p LM 747 70p TAA350 250pTL083 110p7417 30p, 7497 190p 74180 95p 4032 100p CA3161E 150p LM 748 40p TAA550 35pTL0847420 16p 74100 130p 74181 180p 4033 150p CA3162E 450p LM1303N 95p TAA570 250p 130p

7421 30p 74104 65p 74182 90p 4040 100p CA3189E 250p LM 1458 60p TAA661B 150p UAA170XR320

200p250p7422 18p 74105 65p 74184 140p 4043 95p FX209 760p LM3900 60p TAA700 340p

XR2003 150p7423 30p 74107 35p 74185 140p 4046 120p LD130 460p LM 3909N 70p TAA790 340p7425 30p 74109 55p 74188 320p 4047 100p LF356 90p MC1310P 150p TAD100 150p XR2206

XR2207400p4000p7426 40p 74120 115p 74190 100p 4048 60p LF357 90p MC1312P 160p TAD110 130p59p7427 30p 74121 25p 74191 100p 4049 45p LM211H 2409 MC1314P 190p TBA120A 60p XR2208675p7428 35p 74122 50p 74192 100p 4050 50p LM300705 170p MC1315P 230p TBA1205 70p XR2216

7430 18p 74123 50p 74193 100p 4054 130p LM301AN 30p MK50398 650p TBA1207 90p XR2264 440p7432 25p 74125 45p 74194 100p 4055 130p LM301705 4.5p MM 5314 380p TBA480Q 190p XR2265 440p7433 40p 74126 60p 74195 100p 4056 135p LM304 190p MM 5316 470p TBA520Q 190p XR2567 250p7437 30p 74128 75p 74196 100p 4060 115p LM307N 60p NE529K 150p TBA530Q 190p XR4136 150p7438 35p 74130 130p 74197 80p 4066 60p LM308T05 100p NE555 25p TBA540 220p XR4151 350p7440 15p 74131 1009 74198 150p 4068 22p LM308DIL 100p NE556 70p TBA550Q 250p XR4202 150p7441 70p 74132 75p 74199 150p 4069 20p LM309K 140p NE562B 420p TBA560C 240p XR4212

XR4739150p150p7442 70p 74135 100p 74293 125p 4070 30p LM310705 150p NE566 160p TBA641Al2 250p

ZN414 95p7443 115p 74136 80p 74LS00 15p 4071 20p LM311705 150p NE567 170p 764700 200p200p7444 115p 74137 100p 74LS11285p 4072 20p LM 317K 350p SAD1024 1400p TBA720Q 240p ZN1034E

95H90 800p7445 100p 74141 70p 4075 25p LM324 70p SAS560 155p TBA7500 200p11C907446 95p 74142 200p, 4077 40p 1-M339 70p SAS570 150p TBA800 90p 1400p -

IN 4148 DIODES BY ITT/Texas 100 for7447 60p 74143 300p 4081 20p7448 60p 74144 300p 4082 20p £1.50 Shop closed from7450 18p 74145 75p 4093 80p Static RAM 2102 1024 X 1 bit 450 nano sec 21st -28th December.7451 18p 74147 180p CMOS 4501 20p E1.00 each7453 18p 74148 130p 4000 14p 4507 559 2112 256x4 bit 450 nano sec £2.50 Post and Packing 25p7454 18p 74150 100p 4001 14p 4510 100p Murata Ultrasonic Transducers 40kHz £1.80 each Add 15% VAT to total order7460 18p 74151 70p 4002 15p 4511 150p £3.20 pair Minimum order. El 007470 30p 74153 70p 4006 90p 4516 12013

'T.74727473

30935p

7415474155

100p65p

40074009

18p40p

45184520

100p100p POWELL7474 309 74156 859 4011 189 4528 1009 306 ST. PAULS ROAD, HIGHBURY CORNER, LONDON, Ni.. TEL: 01-226 14897475 35p 74157 709 4012 189 4583 809

Barclay/Access credit cards accepted

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 99

100

SOLDER

A high quality standard

solder by limn Multrcore

Ideal for miniaturecomponents 22swg

'dkg

reel, about 163 metres

Order as FY7OM

Price f7.87

SIREN

A small, but penetrating

siren operating on12V DC

It 2A, Dia. 15mm.Order as YB25C

Price £9.11

MIC STAND

Oualay microphonestand extends

to 1 5m Boom armIm long

adjustableStand Order as XB45Y

Price £12.11Boom. Order as XBI6A

Price 0125

POCKET MULTIMETER

Amazing value 4,000ohms per volt DC Jewelled moving

coil meterRanges. DC volts

5 25. 250, 500,AC volts 10,

50.500.1000: DC amps0 to 0 25mA. 0 to

250mA,

Resistance 0 to 6120k ohms,

(Initials -10 to 22dB SIB only

3% a 2s. a l'binches. Complete

with test leadsbattery and

-instructionsOrder as 1I.600

Price £8.75

TURNTABLES

Autochanger complete

with stereo ceramiccartridge and circuit to

make a completelow cost record

player deal for theyoung pop fan

Order as KOWAPrice £16.30

Single play rim driveturntable with stereo

ceramic

cartridge.Order as 06230

Price 124.19

Single play belt drive turntableS shaped tone arm

Order as XI325CPrice £30.63

MINIATURETRANSFORMERS

Good quality mainstransformers to 85415.

6V type secondaries0 6V at

500mA 0 6V at 500mA

Order as WBO6GPrice U.19

9V type secondaries0 9V at 500mA

0 9V at

500mA Order asWB11M Price £2.56

I2V type secondaries0 12V at 250mA

0 I2V at

250mA Order asWB1OL Price (2.19

I5V type secondaries0 15V at 100mA

0 15V at

200mA Order asWB15R Price U.19.

*KENZIE POWERSPEAKERS

High quality. highpower speakers

12in 50W 812 Orderas 00191

Price E18.7912in 50W 1612

Order as 00808

Price £18.7912in BOW Bit

Order as X081C

Price £26.9212in BOW 16.t2

Order' as X0820

Price 826.9215in 150W 811

Order as 00830

Price £57.8015in. 150W 1611

Order as X0841

Price £57.80

SOLDERING IRONSIs KITS

Amex CX von17W miniature

Order as FY62SPrice £4.85

Ater 025 iron. 25W

Order as FR12NPrice UN

CX don with standin presentation

pack

Order as FY6BYPrice £6.85

X25 not with standin presentation

pack.

Order as FYBSAPrice ESA

REVERBERATIONSYSTEM

The 'concert hall'sound in your living

room.

Driver module.Order as 08856

Price £6.11

Requires + aid -I5V 20mA powersupply (reedy

builtl suitable forOmer Module.

Order as YL17TPrice £1.13

Spring line with 3 sec.reverb time

Order as 01.0&.1Price £1.93

Spring line with 7 secreverb time.

Order as XBS4FPrice £11.13

LASER TUBE

A heliumneon0 5mW laser tube

Full details on page262 01 our

catalogue.Order as XLIIM

Price F101.35

AMP KITS

Complete kits of pans with

lull instructions tomake hi fi

.amplifiers with excellent

specificationsBIN amp kit Order

as LW36P

Price F3.8350W amp bit Order

as LW3513

Price £13.73150W amp kit. Order as

LW32K Price £11.89

PIEIO HORN TWEETER

Very simply addedto any

speaker system up to 100W

rms. No crossoverrequired

Distortion <1%.Order as WFO9K

Price £5.27

CLOCK MODULE

Module requires

only transformerand two pushswitches to

operate 4 digs, 0lin red LEO display.

Alarm and radio

outputs Batteryback up when mains

fail Sleep and

snooze timer.Seconds display Just

add speaker for

alarm tone. Fulldetails on page

267 of our catalogue

Order as 0L140Price EOM

KEYBOARDS

High qualitykeyboards with hard

wearing slopingfronted plastic keys

With keys mounted

on nylon bushedsteel levers 49 note

C to C

Order as 00158 Price £23.99

61 note C to COrder as XE1165

Price f29.90

With keys pivoted ona hard wearing

moulded fulcrum

19 note C to COrder as XB17T

Price f19.93

ADJUSTABLE LAMP

Adjustable to gel a bright

light on miniaturecomponents. With

bracket

for clamping orbolting to

bench or wall Shade and

Position fullyadjustable and

stable Finished in white.

Order as XY25C

Price £10.90

FOR FULL CATALOGUEDETAILS SEE

BACK COVER

LIQUID CRYSTAL

DISPLAY

High quality In digit

12 7mm Phan high

figures. Drsnlay hascentre colon for use

n 12 hour clocksand decimal points.

plus and minus

signs and overflowindicator for use in panel meters.

Order as FY89WPrice f8.89

111.111.11RIMPNWPW4'll

20.000 OHMIVOLT

MULTIMETER

A 20,000 ohms pervolt

multimeter at an incredibly

low puce DC volts5, 25,

125 500, 2500,AC volts 10,

50.250, 1.01:03, DC amps0

to 0.05rnA, 0 to 250mA,

Resistance 0 to 50k, 0 to

5M ohms. Decibels-20 to

22dBComplete with test

leads battery andinstruction leafletOrder as YB83E

Price (13.70

QUICK CHARGERECHARGEABLE

CELL

121/. Sue AAIHP11.Fully recharged In

5

hours with 150mA.Capacity. 450mAh.

Will last for at least503 full charge

discharge cycles.Change to quick

charge cells now,

Order as LR7111Price £1.49

MULTIMETER le TRANSISTOR

TESTERSuperb high sensitivity

muhimeter

and transistor testerm one

Sensitivity 1E13,000ohms per volt

DC Ranges DCvolts 0 5. 2 5, 10,

50, 250. 1800; ACvolts 5, 10.50.

250. 1.904 DC current0.01. 0.025.

05, 5, 50. 500mA,10A, AC current

100; Resistance5k, 50k. 5M, 50M

ohms, Decibels-10dB to 62dB

Complete with testleads three

leads for transistortester batteries

and instructionleaflet.

Order as YBB7UPrice E39.30

,r,ces include VAT and postage

and packing, but if total under 14

Prices guaranteed urea February 8th

1903 EVOn customers deduct 13%and expo,- teporrstaalltecuwoill be charged

Please use order code

NI items in stock at rime of going topress

IDpSLlpL All mail to POndonRoad,

Box 3, Rayleighc,,EsslexSS6 RRdf on Sea, Es

xTelephonen.Soutlh

ES Lend 101021554!55

Southend

TEDd MondaYl. Telephone:

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

9V

.91/

R610k

47n

R510k

RI22k

Readers' Circuits

TECH TIPS

R733k

ti

476

RVSIOOk

R9120k

.9V0

R11100k

012103k

7

5

6

Y17 /17110k 6800

A Simple SequencerS. Giles

This is an example of how not to use abucket brigade IC (according to themanufacturer's specifications). Thecircuit shown is basically that of anormal flanger but with two importantdifferences1. The clock modulation oscillator

operates within the audio range.2. There is no input filtering and

output filtering is kept to a mini-mum.

The usual precautions should betaken when handling the TDA 1022(in other words - don't use an ICinsertion clip).

The setting up procedure is as fol-lows

RV2 should be at its mid -point,although this is not too critical. TurnRV5 full on and the clock modulationoscillator should be heard at the out -

020470k

OUTPUT

R2347k

NOTES:ICI IS 7411C2 IS TDA 10221C3 IS 1468IC4 IS 404701 IS 265457

put. Tune this with RV4 to the open6th string on the guitar and then turnRV5 until the oscillator is barely aud-ible. If the guitar is now played withRV1 fully on, both the guitar note andthe oscillator will appear at the output,with the oscillator tending to followthe guitar's change in frequency. Forbest results the oscillator should beturned to the key being used Finally,clock breakthrough can be minimisedby use of RV3, which should prefer-ably be a 20 turn preset.

Tech -Tips is an ideas forum and is not aimed at the beginner. We regret we cannotanswerqueries on these items.'

ETI is prepared to consider circuits or ideas submitted by readers for this page. All itemsused will be paid for. Drawings should be as clear as possible and the text should preferablybe typed. Circuits must not be subject to copyright. Items for consideration should be sentto ETI TECH -TIPS, Electronics Today International, 145 Charing Cross Road, LondonWC2H OEE.

101

OLIVETTI PRINTER & KEYBOARDType 7E300

With PUNCH & READER. Upper case ASCII with V24 Interface 240 -Volt operationE125 each

INFRA RED IMAGE CONVERTORType 9606 (CV 144)

11/4x2" diameter Requires single low current 3KV to 6kV supply. Individually boxedWith data

£12.50 each. P&P 75pInfra Red Lamps also advertised.

TELETYPES KSR33Upper case ASCII with 20MA Loop. This is a printer with Keyboard. (No Punch orReader

on this model).E225 each

HONEYWELL VDU1920 Character Upper Case ASCII. With edit and block transmission. Limited quantitywith data

New Low Price E200 each

TRANSISTOR INVERTOR 115V 50/60 HZ INPUTThese run at 20KHZ They can be modified to be a switching power supply or to provideEHT for VDU. Oscilloscopes, etc., or the output core could be rewound to provide anyvoltage/current within the units rating. As supplied they have multiple outputs. Aschematic is provided. Size 31/4 x4x EP/0". All units supplied with connectors removed tosatisfy the manufacturer's requirements. All units are tested before dispatch.E5.50 each. P&P E1.50

CROWN REPLACEMENTMOTOR

for

IBM GOLFBALLTYPEWRITERS

115V 50HZ 1350 rpm

£4.50 each. P&P f I 51

STEPPING MOTORS6'12 position with additional where the rotor is coils.

Dewce can be used as a Cacho Diagram supplied. Willactually work on 5V 12,24 recommended.

E1.50 each. P&P 75pOR 5 tor E5. PM' El .50

TRANSFORMERS - Standard Mains InputSecondary outputs504 0 125A (15 ea.34400 0.66A min melding 4011 choke E30 the pair232 -0-10)00 0.44A will matching 2011 400MA choke. E30 the parr84 600 Amp, C25.511-020-30-40-513604 40 Amps (25. 5K4 300MA E15.

1204 30MA En.3101 50141 CB ea. 44 250 Ames CIO ea.10.15-254 100 Mips (1518(0 3DMA ESO.

22.504 110MA E50 ea.WV 0.0213 (150.Input MY 50/12 Sec 100K4 0.05 (150.MULTI -PURPOSE MAINS TRANSFORMER 4 wIndIngs each winding 0-10 110 125 al 4.8A.

(15 ea.4150 5014 2 Wee Input. Output B SKY 2 55KVA Could he run on 2404 N rating (15each.ST: 3058 ISOLATING TRANSFORMER Input 220,2504 50117 Output 115V I 8VA BRAND

IEW These are wry conservatively rated (20 ea.

CAPACATORS10m14 IOW DC Working Ed ea.ZmId Nth Ed ea.0.5 rdd 7.504 EA ea.

200mtd SKY Rind discharge. El 0 ea.0 5 mid 7 SKY Ed ea.11mtd 2.500 El ea.

CARRIAGE on these units will be charged at Con

INFRA RED QUARTZ LAMPS. 230V 620 Watts. Size131/2" 1/4" dia. £1 .50. P&P 50p.BRIDGE RECTIFIER. 2 amp. 50p ea.PHOTODIODE DETECTOR 4" fly leads, 25p ca.A SUPERIOR KEYBOARD. Size 3 x 21/2 x 2" high with 12Alma Reed Switches. Blue keys marked in green 0-9 and astar with one blank. NOW Ed mi. P&P 75p.AMPHENOL 17 -way chassis mount edge connectors 0.1spacing, 15p ea.I.E.C. Standard MAINS LEAD. Moulded (3 vertical flatpins -centre offset). 80p es. P&P 50p.FANS, 115V 13 Watts. Size 31/4 x 31/4 x 11/2". BRANDNEW. £4.50 ea. Secondhand £2.50 as. P&P 75p.MOTOROLA REGULATORS, type 7812 12V 1 amp. 85pS.Miniature MOTORS 12V with geared wheel (8 teeth 3 / 16"dia.). Size 11/4x Ya" dia. New, 30p ea.MOTOR 12V DC with pulley and integral semiconductorSpeed Control. New £1 ea. P&P 50pLEDEX ROTARY SOLENOIDS. 115V DC. No switchassembly. 15p ea.DIAMOND H CONTROLS ROTARY SWITCH. Singletide 10 -way. Printed Circuit Mount. New. 10p ea.DELAY LINE. 50 nanosecs, 3 connections, ground -in -out.Size 2X7/16X 5/16". New. 25p es.PULSE TRANSFORMER. Sub -min. Size 1/2 X5 / 16 x 1/4 'Secondary centre tapped. New. 20p ea.

MICROSWITCH. V3 style. Button 250V 6A. 15p ea.MOTOR by Inland Motor Corp. DC High Torque. Reversible.Usable torque at 5V. Max. voltage 24V. E2.50 ea. P&PE1.50.REMO TV type MULTIPLIER. Two high voltage outputsand focus E2 as. P&P E1.DON'T TAKE CHANCES. Use the proper EHT CABLE. 10pper meter or £7.50 per 100 meter drum. P&P £1.50.MOTOR by Eastern Air Devices Inc. 125V reversible withtoothed shaft (10 teeth 1/4" dia.). Size 21/4 X 2%" dia. 75pea. P&P E1.PHOTOGRAPHIC LAMPS. Peari. 230V 500 watt. Screwcap. 75p as. Box of 12 £5.50 P&P El .50.Decoupling CAPACITORS 0.05mfd 10V. Size 0.25"between leads 1/4" height. 100 for El. P&P 50p.CAPACITORS 0.01mfd. Size 5/16" between leads. Va"height. 100 for El. P&P 50p.MYSTERY I.C. PACK. Some 40 pin - good mixture allnew devices. 26 IC. for E7. P&P 50p. You find out whatthey are and we will buy the information from you.SUPERB 19" RACK CABINET. Approx. 4' 6" high x 33"deep. Instrument front panel position can be adjusted.Chocolate colour. These are new but have slight scratchesand imperfections - hardly noticeable. E35 each. Carr E4VACUUM PUMPS - TRAPS, ETC. Send for list.

LISTS AVAILABLE NOWWe still have large quantities of miscellaneous items which we have listed at unbelievably low prices.Phone us your address or send a postcard for your FREE list.

TER scope 545A sole H plug-in El 25 ea.TEN scope 545A with CA plug la (175 ea.H.P. nape I 75A 500111 Dual trace E175 ea.Single trace (125 ea.MAINE KERR Untversal 11611p. CT375 (75 ea.MARCONI Ware Analyser 112330 E500 ea.MARCONI Audio Oscillator T1I101 20112-2001012 E45 ea.MARCONI Valve Voltmeter TTIMIC E30 ea.NOISE GENERATOR CT410 - corers INN le WS C8 ea.

NAGARD Rise Generator 5002C E50 ea.MARCONI Wan Analyser type 11455E E50 ea.SOLARTRON DIM LMI420 with AC W11111471 840 ea.CALCOMP Drum Honer type 564 (1.500MARCONI Bridge TF8688 E120RANK Flutter Meters ESO ea.

HEWLETT PACKARD Srgnal Gen 60813 E240ueo Signal Generator NF 135 E120 ea.MARCONI Magnification Meter 171245 with TF1246 (175MARCONI Magmfirabon Meter TFI245 with TF1247 E175

VARIACS Est. wooer Good coadlhoo. Soup 825 ea.10 Amps E35 ea.Sane 3 pease available Plane enquire.Carnage all units El ea.

CRYSTALS 19.20H2FLAT METAL CASE. /RAPID NEW

50p EACH

EX -NAVAL MI ea STEEL DISHES. NEW CRATED. Ill deep al centrerse are plain steel dishes with holes Or various aerial eptIons C22.50ea.Carnage Lb

10 -Way Multi -Colour Ribbon Cable. New 40p per metre. P&P 50pSPEAKERS 2 -in 50 ohm 0.2W New 40p each. P&P 50pRAPID D1SCNARGE capacitors Pall 4101 E5 each. P&P 11 50GEC UHF 4 Ninon tuner (2.50 each. P&P 85pBIG INCH Motor 1104 AC 3 rpm 50 cycle - very small 50p each. P&P SOpCENTAUR 1159 FANS. Brand new 4 5 4 e I 5in. (4.50 each. P&P 75pFa -Used Eqsapment - tested 60p each. P&P 75pPOTTER 4 BRUMFIELD TIMER/RELAY. 1154 AC Heavy duly 2 pole c o with 3 second

delay Dope R & C lor ddlerenl liming 50p each. P&P 85pCONTRACTORS. Heavy Dull 244 DC 5 make El each. P&P 85pGEC UNE/V11 6autIon tuner (4.50 each. P&P 11DIGITAL 24 -HOAR CLOCK with buill in alarm as used in Braun Molts! clocks &Lent

running large Iligninated numerals. AC mains Sue 6 s 2ti ONLY 0.75 each.P&P 50e93IA PNOTOMULTIPLIER in stainless steel container vett, window and built in resistornetwork E2 each. P&P 11SLIDER CONTROL 50011. Log Single neck Complete with knob Length 3 -'' 25p

each. P&P 25pRANCO 250V 16A DIERMDSTATS with Control knobs caltbrated 50 200 degree I(2.50 each. P&P IISOLID STATE UHF TUNERS. 38 mss El each. P&P 75pBRAND REX blue wire wraps 30 metres for El. P&P 25pSin. SOLID RUBBER RI/46011in du ruliberl Keep [he kids for doll happy 4 for El.P&P 11 25

TRANSFORMERSAUTO 2409 input 115V I Amp output. E1.25 each. P&P EI.25.2409 input Sec. 64 1.56A Mae VI e 2 K Be Goad meta. 81.50 ea. P&P El.2409 main SOC. I24 0.92A. Site 211 e 2 a 2fia Geed haellly. EI.50 each. P&P II2409 input Sec. 124 IDONA. Size BO a 40 0 42n. 50p each. P&P 75p.2400 input Sec 120-129 500. Sas 9 II 45 a 40 El each. PAP 75p.1159 opal Sec 5V 250MA. Size I 11/16 A 1.5/16 A I' Y. 2 for 50p. P&P 75p.

SEIMCONDUCTORSAt 2p each1X3063.15441.1 5p each.IC147.1E1483 8C151. BC158. BC237 BF 197, 0A90. 0491 BA154 BA243At 25p each71P3I T1P4IA. 2%5296. AF 139. 1TX34184127 lOpt BEIER 20p 110239 40p: 10241 Opt MJE340AT 4Opt 80222 50p.B0233 & 00234 Camp Parr 25W - 50p per pr. or 50p each.Regulator TBA635 8 to 200 ie - 54 out 1000 1135 Can 50p each. 012580 20p.TV AMPURER TRA120 20p each.

Integrated CIrcuits

/453 50 709 15p 75325 E1

7451 5P 74H74 12p SNI5862 Hp

7401 Sp 741,51 7p MC4028 sea7402 12p 74538 10p 7417 14p7476 20p 74502 12p 7441 40p7495 35p 741 54 70p

MOTOROLA DUAL in Line 6 pin Opus Coupler 30p each. Gold platetester yermon 50p oath.AM11140-4K RAMS STATIC 5 Volt ceramic Ea each.2708 E5.50 each. P&P 25pTELEPHONES. 706 style. Black or Grey 05.50 mach. 746 style Blackor Grey E7.50 puce. Older style Black £2.50 each. Postage Et eachoneywell humidity Controllers 50p each. PAP 40pTHYRISTOR TIMERS. Solid State 15 secs adjustable (reset) in plasticrelay case Standard 7 pin base Series delay 50p mach. P&P 85p

' MINIATURE PC MOUNT SLIDE SWITCH. Single pole 3 -way 10pwad,DIGITAL to ANALOGUE CONVERTOR. &ha writ lit standard TTIsocket With data E2.60 each. P&P 25pVARIACS. 2 amp Standard 240 Volts E10 arch. P&P El 50ELECTROSTATIC VOLTMETERS. 7 5KV E5 weh. P&P El Otherranges available Please enquireTRIMMERS. Sob min 0 2510 1 25p1 Ito 4 501 7 to 45p1 AH toe Sp

Minimum order £3 value of goods. P&P or Carriage and VAT at 15% on total must be added to all orders

CALLERS VERY WELCOME STRICTLY BETWEEN 9am-fpm and 2-5 pm Monday to Saturday incl.BARCLAYCARD (VISA) and ACCESS taken. Official orders welcome.

LT7NORWOOD ROAD, READING TEL NO. READING 669656

(2nd left passed Reading Tech College in Kings Road then first right Look on right for door with spoked wheel)

102 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

Readers' Circuits

R110M

Car Horn RepeaterI. Hopkins

This circuit allows the horn to soundeither continuously or repetitivelywhile the horn switch is pressed. Thesecond option is activated by pressingthe horn button twice in quick suces-sion.

When SW1 is pressed initially,gates IC2a and IC3d propagate thesignal, turning on transistors Q1 -Q3and sounding the horn in the conven-tional manner. Releasing SW1 trig-gers the monostable IC1 (a 555timer). If SW1 is pressed again whileIC1 is active, flip-flop IC3a / b is set,enabling oscillator IC3c and causingthe horn to operate intermittently as

NOTES1C2& IC3 ARE 4093

TOHORNRELAY

0

long as the switch is closed.LED 1 is optional and monitors the

operation of the horn - very usefulduring testing. The oscillatorfrequency can be varied by alteringC9, while the monostable period isadjusted using R2 and C5. C3 and C6suppress the effects of switch bounceand R7 sets the mark /space ratio ofthe oscillator to approx 3 1.

IC1a

R2Cl220n

R310MT 6M8

+ TUNERSUPPLY(20V MAXI

0 +Ve

1k0

LED1

Touch Station SelectorJ. P. MacaulayThis circuit, used in conjunction withan FM tuner, will enable stations to beselected by means of a single touchpad.

IC1aINPUT

0.1" MATRIXVEROBOARD

VAR ICAP SUPPLY (MAX 15V)Vdd

14 RV1

RV7

TOV AR IC APS

0D1

D8

RV1 -7 ARE 100kD1 -8 ARE 1N914

01 IS BC109e

Under quiescent conditions theoutput of IC1a is high. In conse-quence the output of ICI b is low andthe astable formed around IC1c/d is

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

disabled. The astable produces anoutput square wave of 0.5 Hz, whenenabled. When a finger is applied tothe touch pad IC1 a's output goes lowsending IClb's output high, enablingthe astable whose output is loadedinto the decade counter, IC2. The tenoutputs go high sequentially with theleading edge of the square wavesprovided by the astable. When thefiner is removed the counter will'freeze' retaining the last count.

Tuning is accomplished by thepresets attached to the outputs of IC2.As shown, the circuit caters for sevenstations but this can be extended toten by making similar connections toall the outputs. Diodes D1 - 7 ensurethat the individual tuning voltagesdon't interfere with one another whilstD8 helps to stop drift due to tempera-ture variations. In order to knowwhich station has been selected thedisplay and driver transistor is fitted tothe outputs.

In this manner a LED correspon-ding to the chosen station is dis-played. The touch switch used in theprototype is simply a small piece of0 1 inch vero with alternative stripsconnected together.

If the outputs of the decadecounter were to be connected toCMOS transmission gates the circuitcould also be used as a multiwayswitch for audio signals.

103

WilmslowAudio

THE firm for speakers!Send 30p stamp for the world's best catalogue ofSpeakers, Drive Units, Kits, Crossovers, etc., and

discount price list.

AUDAX BAKER BOWERS & WILKINS CASTLE CELESTION CHARTWELL COLES DALESFORD DECCA . EMI EAGLE ELAC

FANE GAUSS GOODMANS I.M.F. ISOPHON JR JORDAN WATTS KEF LEAK LOWTHER McKENZIE MONITOR AUDIO

PEERLESS . RADFORD . RAM RICHARD ALLAN SEAS TANNOY VIDEOTONE

WHARFEDALE SHACKMAN AUDIOMASTER TANGENT STAG YAMAHA

WILMSLOW AUDIO Dept. ETISWAN WORKS, BANK SQUARE, WILMSLOW

CHESHIRE SK9 1HF

Discount HiFi, etc., at:5 Swan Street

TEL. WILMSLOW 529599 FOR SPEAKERSWILMSLOW 526213 FOR HI-FI

CH1PTESTERFOR NASCOM I

Brand new fantastic product for Nascom 1 owners. Use your Nascom to test allthose surplus and suspect ICs and sort out the good ones from the duff ones.

Just clip the IC in to the test clip provided and use the Nascom to examine thelogic levels on each input and output. A graphical representation of the chipshowing all pins and their logic levels is shown on the screen.

Tests all 5V TTL ICs up to 16 pins. Includes commands for automatic andmanual testing of logic levels of all inputs and outputs simultaneously.

All inputs may be changed under keyboard or program control includingcontinuous test mode.

Propagation delays may be calculated using an oscilloscope.

Routines to test ICs may be stored on cassette for later use.

Uses 2 ports on minimum Nascom system. No expansion whatever required.

Comes complete with all parts, full comprehensive instruction book, cassettewith program and sample programs for popular ICs.

Send s a e for free descriptive leaflet.

Price inclusive of VAT and postage

£19.50Stockists of Apple Micro Processor and Peripherals

Access and Barclaycard welcome

STRATHAN D44 St. Andrew's Square, Glasgow G1 5PL

Tel: 041-552 6731 or 2.Telex: 777268 (24 hours service) O

BARCLAYCARO

A Range of Performance from...HAMEd

HM307 SingleTrace DC-10MHzPlus Built in ComponentTester

HM312 Dual Trace DC-20MHz.5mVic m. Ful I X -Y, 30MHzTrigger. Plus TV Trigger 250

HM412 Dual Trace DC-20MHz,2mV/cm. X -Y, 40MHzTrigger. Plus Sweep Delay 350

HM512 Dual Trace DC-50MHz.5mV/cm, X -Y. 70MHzTrigger Sweep Delay.Plus Single Shot. SweepDelay and After DelayTrigger 580

HM812 Dual Trace as per HM512Plus Storage. AutomaticStorage and VariablePersistence

For FULL DETAILS andDISTRIBUTOR LISTContact

Prices UK List ex VAT

Hameg Ltd.,74-78 Collingdon St.,

Luton,Beds.

LU1 1RX.

PERFORMANCE AND RELIABILITYARE THE SEALS FIRMLY STAMPEDON THE COMPLETE HAMEG RANGE

AND IT IS A COMPLETE RANGE

Tel: (0582) 413 174ELECTRONICS TODAY INTERNATIONAL - JANUARY 198(104

Readers' Circuits

C1100n

°11I

Vin

O

R1100k

IC1LM301

C230p

2k7 C13 IF/PR10

..4

6-1 C14

3

\SW1hMID-RANGEFREQUENCY

R24k7

BASSBOOST/CUT

R310k

1C322n

R410k

RV2100k

RV1100k

R539k

TREBLEBOOST/CUT

I C41500p

SW1a

C31n0

100kIC4LM301

C830p

1n5

IC2LM301

C630p

R61k0

R910k

RV310kMIDBOOST/CUT

R71k0

R810k

Audio EqualiserJ. CollinsThe circuit is a versatile line levelaudio equaliser providing many of theuseful functions of a multi -channel

equaliser but using only one bandpass filter and, therefore, far fewercomponents.

IC1 acts as a buffer, providing aninput impedance of 100 k. R2 and C3give HF roll -off at around 30 kHz. IC2

IC3LM301

C730p

0Voni

NOTES:MID RANGE

FREQ.C9, C14 - 2n5 - 4KHzC10,C15 - 5n - 2KHzC11,C16 - 10n - 1KHzC12,C17 - 20n - 400HzC13,C18 - 50n - 250Hz

RV1,2,3 ARE LINEAR

and associated components form afamiliar bass/treble tone controlgiving 20 dBs of boost and cut. IC4 isconfigured as a multi -feedback typeband pass filter with a Q factor of 3and a centre frequency selectable bythe switched capacitors C9 to C18.This band pass filter is connected in afeedback path of IC3, giving up to 20dBs of boost or cut at the centrefrequency by varying RV3.

All three potentiometers give noboost or cut at their centre (midway)positions and give a smooth increasein boost or cut on rotation to the rightor left respectively.

Relay Power SaverL. Goodfriend

When power is at a premium kusualli.in battery circuits), this circuit can beused to save 20% or more of the

.power used by a relay.Since the pull -in voltage of a relay

is several volts more than its drop -outvoltage, there will be no noticeableeffect if a resistor is switched intocircuit when the relay pulls in. This isvery simple to achieve. Any contactwhich carries the coil voltage of therelay can be used to bypass current

limit resistor R1 until the relay isenergised. When power is applied tothe relay, all the necessary currentflows through this contact, but whenthe relay pulls in, the current has toflow through R1, which reduces thepower drain.

The value of R1 must be deter-mined by experimentation; try about aquarter to a fifth of the relay's coilresistance. Bear in mind that the on -

load voltage of a battery decreaseswith use, so while a resistor may seemto be suitable with a new battery, therelay may start to drop out when thebattery ages.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 105

Tr0

-r.110 electronics

DEPT. E.T.I. 56, FORTIS GREEN ROADMUSWELL HILL, LONDON, N10 3HN

SPECIAL OFFER FOR ETI AND CT READERS ONLYDynamic RAMs4027 3.054116 (250ns) 7.944050 (200ns) 2.884050 (35Ons) 2.714060 (300ns1 2.88

Static RAMs27024.2 1.214035 (1000ns)1 .142111A.1 1.962114 6.904045 (25Ons) 6.565257=4044 7.666810 3.11

C.P.U.s68008080A9900JL

EPROMS1 70252 709

Buffers7436574366743677436881LS968ILS9887288T9587968T98

6.565.70

28.75

4.717.13

.48

.48

.48

.48

.66

.661.611.441.441.44

Interface82128224822882518253MM 5303MM 5307

2.133.515.245.877.825.299.08

741 5 for E1

74 Series TTLLS N

7400 177401 177402 -7403 --7404 187405 207408 207409 -7410 --7411 -7412 -7413 -7414 75

3020

7420742674277428743074417442 -74474--7450 -7451 207453 --7454 -7460 --7470

.1- 1

.11

.13

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.14

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.18

.18

.22

.44

.12

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.12

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LS7472 -7474 -7475 -7476 347478 347485 -7486 --7489 -749074927493 -7495 727496 -74107 -74121 -74122 -74126 3574141 --74145 -74150 -74151 5174153 -74154 -74155 7574156 --74157 -74160 9874161 --74162 -73163 6974164

.20.23.29.20

1.04.18

1.50.28.33.28.40.48.22.23.33

.46

.46

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.43

.68

.46

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.40

.57

.56

.57

.49

.6074165 .5674166 1 6974170 1 31 _

74174 - .5874175 .5874180 .4374181 - 1.4474184 - 1.1474185 1.2174188 POA 2.02

741907419174192741937419474195741967419774198742217424 774251742537427374279742837429374348743657436674367743687439074668

LS

90859590

N.52.49.50.51.44

- - .7985 -.-- .9995 1.05

- - 1.35- .811 20- 1.2755 --65 1.1380

1 31 -

50 .5750 .57

-- .5750 .57- - .981 68 -

555 4 for £1

L series74L90J

S series74S0074638774647474S262

75 series75107AJ75107 BJ75108AN754528

1.15

301.448.28

12.65

1.151.151.03

.29

USE OUR "ORDER RING" LINESOM IIAMMO

q. I!"VAT INCLUSIVE PRICES. P&P 25p

01-883 3705/2289

Please add 30p for P&P

DELTA TECH & CO.62 NAYLOR ROAD, LONDON, N20 OHN

All prices VAT inclusiveRESISTORS (1/4w E12)10 ohms to 10 Mohms 1.5pPRESETS (.15W HORIZONTAL)100 ohms to 2 Mohms 8pPOTENTIOMETERS (Carbon)Log and Linear4 7 Kohm to 2 2 Mohm 28pVEROBOARDS (0.1" Copper)2 5" x 5" 52p3 75" x 5" 62pZENER DIODES (400mw)2V7 to 33V 8pTRANSFORMERS (240v)9-0.9v. 100mA flOp0-15V. 0-15V. 200mA 100pCERAMIC CAP (50V)22pF to 50nF 2pPOLYSTYRENE CAP (50V)10pF to 1 000pF 5pPOLYESTER CAP (100v)1 nF to 100nF 5p15 22. 33 6p47 68 10p11,F 12p 2 2,iF 20p3 3aF 24p 4 70 28p

ELECTROLYTIC CAP (sF/V)1 25 to 47/2568 50. 100/35150, 25, 200/12220/25, 250/12470/25. 500/301000/101000/251500/252200/6.3

6p8p9p

10p13p13p20p24p20p

BRIDGERECTIFIERS

VOLTAGEREGULATORS

Ub 25p 320H-05 40p7I) h0ov 30p 32014.24 40p

A 5115 22p 7805 70p1.4 100V 27p 7812 70p14 200V 32p 7815 70p14 400V 34p 7818 70p2A 50V 40p 7824 70p24 100V 42p 7905 90p24 200V 48p 7912 90p2A 400V 55p 7915 90p

7918 90p7924 90p

106

OPTO/ DISPLAY2N5777 55pOCP71 65pORP12 60pMAN72 110pMAN74 110p

125" & 2"LEDs -Red 10pGreen 14pYellow 14p125" clip 3p2" clip

DIODESBY1270A470A91042000A2021N9161N41481N40011 N40021N40031N40041N40051 N40061 N4007

4P

10p8pBp6p9p5p4p4p4p5p6p6p8p8p

1N5400 13p1N5401 14p1N5402 15p1N5404 16pOIL SOCKETS8 pin14 pin16 pin18 pin22 pin24 pin28 pin40 pinLINEARCIRCUITS709710-14741-8

11p13p14p18p22p24p28p40p

40p33p22p

747.14 48p748.8 44p ,CA3018 70pCA3028A 85p

CA3046CA3054CA3080CA3130CA3140LF351NLF356NLM301ANLM308NLM318NLM324NLM339NLM348NLM377NLM380NLM381NLM382NLM1310NLM 3900NLM3909NMC1496PNE531NE555NE556NE566TE1/16414TBA641BTBA800TBA8105ZN414ZN1034

CMOS40004001400240064007400840094010401140124013401440154016401740184019402040214022402340244025402740284029

Model 146

LOW COSTAUDIO SIGNALGENERATORS(Sine & Square Waves)

10Hz-100kHzVery low distortion (-0015%)

£41.40 (or in kit form) £35.65p p and ins. £2

Model A0113. Sine/Square. 1 voltinto 6000. Dist 0.2%. £31.60 (Kitversion £26.50) p.p. Et .

TELERADIO ELECTRONICS325 Fore Street, Edmonton, London N9 OPE

S.A.E. for leaflets Closed all day Thursdays 01-807 3719

LOUDSPEAKER. High quality 8" loudspeaker, 10 watt RMS 8 ohm. Rolledsurround with aluminium centre cone. E5.00 + E1.00 P&P.

STEREO MAGNETIC CARTRIDGE BARGAIN. Acos M6EX stereo magneticcartridge with tapered bi-radial -diamond styli. Recommended tracking weightbetween 1 and 2 grms. Output 2.8 MV into 47 Kohms. 12.5mm 11/2 inch) fixingswith a recommended retail price of £27.00. This is offered at a very special price ofE9.00 (Post Free).

AERIAL Useful telescopic chrome di -pole aerial. Both elements swivel and extendfrom 130mm to 500mm. Complete with black moulded mounting bracket and short75 ohm co-az lead. E1.50 + 40p P&P.

ELECTROLYTIC CAPACITORS (CAN TYPE). 3300 pf 25wv - 40p + 30pP&P 2500-2500 mf (Dual type) 63wv. 70p + 30p P&P.

TRANSFORMERS (0.240v primaries). 16v -0-16v @ 2 amps £2.50 + £1 .00 P&P.Dual voltage 0-12v, 0-35v @ 4 amps or 1.5 amps respectively £2,50 + £1.00 P&P.

MAIL ORDER ONLY (DISCOUNT FOR QUANTITY)Cheque / Postal Orders with Order Please

B.K. ELECTRONICS37 Whitehouse Meadows, Eastwood

Leigh -on -Sea Essex SS9 5TY

70p 4030 48p 744570p 4035 107p 744675p 4041 78p 744790p 4042 58p 744845p 4043 83p 745065p 4044 90p 7451

75p 4047 90p 745332p 4048 55p 745460p 4049 30p 7460

200p 4050 30p 747074p 4066 38p 7472

60p 4069 18p 7473

90p 4070 18p 7474175p 4071 18p 7475

75p 4072 18p 7476140p 4073 18p 7480130p 4081 18p 7485150p 4082 18p 7486

55p 4086 80p 749070p 4510 73p 7491

85p 4511 99p 7492105p 4516 95p 7493

25p 4518 72p 749460p 4520 69p 7495

140p 4528 99p 7496200p200p

75p110p100p200p

TTL7400 I 1 p7401 11p7402 11p7403 11p7404 13p

7497741007410574107741097411074118

7405 13p 7412118p 7406 15p 7412218p 7407 20p 7412318p 7408 13p 7412560p 7409 13p 7412618p 7410 13p 7413284p 7411 17p 7414132p 7412 15p 7414242p 7413 27p 7414518p 7414 48p 7415018p 7416 25p 7415132p 7417 25p 7415385p 7420 13p 7415463p 7421 21p 7415537p 7422 16p 7415657p 7427 25p 7415768p 7428 28p 7416045p 7430 13p 7416192p 7432 18p 7416290p 7433 30p 7416385p 7437 15p 7416418p 7438 15p 7416547p 7440 10p 7416618p 7441 56p 7417332p 7442 43p 7417454p 7443 35p 7417563p 7444 78p 74176

65p65p531362p10p12p12p10p12p17p21p24p24p30p26p25p66p22p32.p28p17p32p30p30p42p

200p60p43p20p25p40p88p26p22p40p34p34p48p45p

200p55p69p48p52p89p54p30p52p64p50p66p66p66p45p85p70p50p60p64p

74177 53p74180 50p74181 99p74182 30p74190 75p74191 70p74192 50p74193 64p74194 68p74195 65p74196 80p74197 40p74198 107p74199 80p

TRANSISTORSAC126/7 20pAC128 20pAC1281176

Mt pr 40pAC176 20pAC187, 8 21pAD149 60pAD181 2 40pMATCHED161/2 100pAF I 24 34pAF139 35pAF239 45pBC107 10pBC108 / 9 10pBC147 8pBC148 10pBC149 9pBC157 10pBC158/9 10pBC167 13p801690 13pBC173 6p8C177.8 16pBC1798 18pBC182 '3 10pBC184 10pBC209 11pBC212. 3 11pBC214 14pBC214L 14pBC2618 14pBC461 34pBC477 23pBC478 9 23p8C547 P 12pBC549 15p80557 6 13pBC559 15pBCY 70 16pBCY71 19pBCY72 18p80115 40p

80131 1280135.'6BD137 / 8BD139BD140BF180BF181BF184BF185BF194 /58E196/7BF2448BF259BFR39BFR79BFX29BFX84BFX87BFX88BFY50/ 1BFY52BRY39BSX20BU205BU208MJ2955MJE340MJE2955MJE3055MPF 102MPF 103MPF104MPF105MPF106MPSA06MPSA56MPSUO60035TIP29TiP29BTIP30T1P3013TIP31TIP32TIP33TIP33CTIP34ATIP35CTIP36ATIP41ATIP42AT1172955T1P3055ZTX107ZTX108ZTX109Trx 300TrX301:1, /117

38p35p35p35p35p24p8p

21p25p10p10p35p25p32p32p25p25p22p27p22p18p45p22p

140p200p110p70p

104p85p40p40p40p40p46p26p26p61p86p35p40p35p40p35p35p40p60p65p

200p220p

60p60p70p55p13p13p13p16p18p20p

ZTX303 24pZTX304 27pZTX311 19pZTX341 22pZTX500 16pZTX501 16pZTX502 21pZTX503 17pZTX504 28p2N696 33p2N697 13p2N698 30p2N706 14p2N914 34p2N918 33p2N1131 20p2N1302 38p2N1303 60p2N1304 55p2N1613 25p2N2222A 21p2N2369 17p2N2484 30p2N2646 50p2N2904 23p2N2905 23p2N2906 17p2N2907 23p2N2926G 11p2N3053 22p2N3054 50p2N3055 50p2N3442 150p2N3702 to2N3711 11p

2N3772 180p2N3773 330p2N3819 21p2N3820 55p2N3823 70p2N3866 60p2N3903 10p2N3904 10p2N3905 10p2N3906 10p2N4037 33p2N4058 14p7N4059 12p2114060 14p2N4061 14p2115457 35p2N5458 35p2115459 35p2N6027 45p

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

ambit

IT'S HAPPEIMED AG= !THE PART THREE CATALOGUE 15 PUBLISHED 1IL WE HAVE MOVED TO BIGGER PREMISES.

e it's here at Iasi - the all new Part Three Catalogue. Fun for all the family. and the usual update on all that is new. worthwhile andexciting in the world of Radio and Communications. A big section on frequency synthesis welting= covering broadcast tamers. to c tttttt nunicationquality transmitter systems. More new products than ever - RADIO CONTROL parts, crystal filters, ceramic filters fur 455kHz and the new rangeof TOKO CFSII low temperature coefficient types for 10.7MHz. Details on new radio ICs. including the new HAI 1225. the CA3IM9L loolsalikewith 84dB signal to noise, and adjustable muting threshold. Radio control ICs - and au updated version of the RC%I&L 8 channel FM receiver -

now with an Ambit designed screened front end, with 27MHz ceramic bandpass filter. LCD panel clock timer modules - the neatest and best LCI)panel DVM vet (only £19.45 each + VATI. the new 5 decade resolution DFM3 for LW HF'VHF with LCI) readout. The DF116 with fluorescentalispla to 1(lkHz resolution on VHF. !kHz on SW. A IkHz HF synthesiser with five ICs - the list is endless. Get your copy of the catalogue now.Post publication price is 60p tine PP etc). The previous two sections are also required for a complete picture: Parts I & 2 the _pair All 1 Cl i()And don't miss our spot the gibbon contest. together with a quiz to see if you Call spot the differences hetween a neohthic caw drawing ant acircuit diagram of one of our competitor's tuners. I* Yes. we still haven't learnt how to spell.)

Updated RCME FM radio control RX kit

8 Channel RC receiver IFM)Single IC RF/IF/DetectorSingle IC decoder

27MHz ceramic filter inputFET RF stage with doubletuned bandpass filterDual ceramic filter IFBased on RCM&E FM systemBest quality SLM servoconnector block

ONLY £16.10 inc VAT (kit)(includes new SLM casel

New i,eries of radio modules in fully screened cans:

There is a danger when advertizing in somemagazines that because we do not findspace to list everything we sell in every ad.,that some readers forget about half the rangeswe stock. So to summarize the general ranges:TOKO Chokes, coils for AM/FM/SW/

MPX, Audio filters etcFilters: Ceramic for AM/FM,LC for FM, MPX etc.PolyvariconsICs for radio, clock LSI, radiocontrol MPX decoders etc

Micrometals Dust iron cores for toroidsfor resonant and EMI filtersToroid mounts

Hitachi Radioiaudio/mpx linear ICs100W MOSFETs, small signalFETs, MOSFETs and bipolar

DOES YOUR ONE GLOW GREEN IN THE DARK ??Our DFM4 does, since it uses a vacuum fluorescent display for direct readoutof MW/LW/FM. Basically the same as the DFM2, ILCD Version). £24.45 kit (Inc VAT)Transformer with all necessary windings for DFM4 E2:50 inc VAT.

Not illustrated here but also now available is the DFM6. This is a vacuum fluorescent displayversion of our immensely popular DFM3 (LCD). Resolution is 100Hz to 3.9999MHz. 1kHz to39.999MHz, and 10kHz to 200.00MHrt; all standard IF offsets (inc. 10.7MHz on shortwave)are available via diode programming.

UM1181 VHF band 2 VARICAP TUNERHEAD5 tuned errcuit. with image/spurii better than -80d13. buttered LOoutput, MOSFET RF stage, FET IF ;ammo, tunes with only 14 to 8v.-9d8m 3rd order intercept. loft price E12.00 inc VAT. 1100of1/ OAI

911225 FM IF strip with all mod cons for the HiFi tuner:All types use 80=d8 S/N Hitachi IC, with muting, AFC, AGC, meteroutputs for signal level and cacti. se o. IF dreamy stage.'A' Dual linear phase ceramic filters, with MOSFET 1AGC'd) IF

mistime and a 3rd narrow filter with DC filter selection. Dualtuned FM detector stage. E2195 Inc VAT (built)

'8' Dual ...me filters, single tuned detector smile E14.95 inc VATlAll 'A' serves units are set up with a spectrum analyser for best THD)

91072 AM RADIO TUNER MODULES DC TUNEDand DC SWITCHED Available February '80All include buffered LO output, mechanical IF filter (TORO CFMOI1.100 tuning bias, switching by a single pole to earthA MW/LW 1150 to 350MHz LW range) with ferrite rod antennaEl As 'A' but also including SW1 or SW2 Ispecify.1

STNt = 1.8 to 4MHs SW2 = 5 to 109114sC With both SW rangesPrices -one off INC VAT'A' E14.43 E15.90: 'C' E17.50 'Custom types OA)

And the following groups of products from abroad range of sources:Semiconductors -specializing in radio devices,Plessey SL1600, EUROPE's best selection ofAM/FM and communications devices. PowerMOSFETs, WORLD's LOWEST NOISE AUDIOsmall signal transistors, BAR graph LED driversfor linear and log.CD4000 series CMOS, TTL/LPSNTTL, standardlinears (741, 301, 3080 etc). MPUs, memories.Small signal transistors from AEG BC237/8/9families etc. (1000 off BC239C : 5.2p ea)LEDs: AEG 3mm/5mm round, 2.5x5mm flat,red, greem, orange, yellow. The best pricesyou will find for quality products.MOSFETs for RF signal processing, includingthe 8E960 UHF device, and 3SK51 for VHF.Varicap diodes for 17:1 capacity ratio tuning

rFREQUENCY READOUT LSI from OKL witha one -chip answer to most digital frequencydisplay needs land various modules).Crystal and ceramic ladder filters from leadingmanufacturers, ferrite rods, various ferrite beadsand a range of crystals for 'standard frequenciesand both AM and FM radio control at 27MHz.Trimmer capacitors.METERS a new range of linear movementtypes, plus many 'indicator' types for VU, alltypes of tuning indicators etc.SOCKETS a new range that are better qualitythan Texas low profile, yet better priced.Modules for AM/FWSTEREQ complete kitsfor tuners, audio amplifiers from Larsholt.SWITCHES - complete low cost DIY systemsfor push button arrays, keyboard switches.DOUBLE BALANCED MIXERS MCL SBL1,replacement for MD108 etc. And cheaper.

OUR LATEST MOVING EXPERIENCE :: At last, we have moved to the address below. There is car parking for customers approaching viaNorth Service Road (an extension of North Road Avenue, entrance opposite the Brentwood Fire Station.) Pedestrian access from the High Street(alongside 117 High Street). The new building is six times bigger than our Gresham Road offices, and we will be installing a much expanded salescounter in the fullness of time NEW TELEPHONE NUMBER 10277) 230909, TELEX NUMBER las before) 995194 AMBIT G. See you there I

200 forth Seruice Road, Brentwood,Essm.ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

1 0 7

ATARI VIDEO COMPUTER SYSTEMcomplete with combat cartridge mains trans-former and aerial switch over box, extra cartridgesinclude - Air Sea Battle, Space War, Outlaw,Video Olympics, Breakout, Basket Ball, Surround,Blackjack, Basic Maths., Bowling, Street Racer,Codebreaker, Hunt and Score, Brain Games, Golf.Skydiver, Superman, Basic Programming, VideoChess and Backgammon.

EXTRA CARTRIDGES: Most at £14.95CHESS £45: Backgammon £34.50

f

VPHIIJPS 67000 VIDEOPAC COMPUTER

PAC 1 - Motor Race, Spin -out, Cryptogram,PAC 2 - Paris, Space Rendezvous, Logic, PAC 3- American Football, PAC 4 - Air -Sea and TankBattle. PAC 5 - Blackjack. PAC 6 - Ten PinBowling, Basketball. PAC 7 - Maths, Echo. PAC8 - Baseball. PAC 9 - Computer (Assembler andMachine code). PAC 10 - Golf. PAC 11 - SpaceConflict.

G7000 - £149.95 inc. VIDEOPACS

most each -£12.95 inc

FAIRCHILD GRANDSTAND VIDEOGAME £74.99

19 Cartridges available £11.95

STOP AUTO THEFTEasy to install electronic lock prevents thievesfrom stealing your car! Only you can start theengine with your private 4 -digit code'NO SPECIAL TOOLS!

NO DRILLING!INSTALLS IN

MINUTES! 11.800 possible

codes provide greatsafety

Turn off for carwashes, parking, etc.

State-of-the-art elec-tronics

Easily hidden fromview

CAR CANNOT BESTARTED BY CUT-TING CABLES,CROSSING WIRES,etc.

£29.95

STEAL STOPPER £29.95

RADIO/GAS LIGHTERRADIO SPECIFICATIONSPower Source: DC 1.5VOne "AA'' size ,UM -3)battery.Frequency Range: AM525-1605 KHz.Transistors: 6 transistors.Speaker: 5 cm.Power Output: 80mW.

EB.95

ADAMComputer controlled electronic game selectablefor four games and each game has variations allexplained in the instruction booklet.* Bounce is a game of skill & reaction played witha "ball"' which progressively speeds up until onlyone player remains the winner.* Ditto. Adam challenges you to outwit its ownmemory by repeating a sequence of lights &tones.* Pathfinder is a maze game - but beware awrong turning returns you to your starting placeand to progress you must retrace your pathcorrectly.* Memory Tune allows you to program the Adamwith up to 30 notes and patterns on the 4x4display and replay your tune as many times as youwish. A tune book with 30 tunes to play isincluded.* All the games include visual display on theplaying board and sound effects

GRANSTAND ADAM £19.95

RING LANGUAGETRANSLATOR

Vocabulary of 1500 words/ moduleModules available:

German, French, Italian, EnglishTranslator £149.95

Modules £18.95 each

00111111111111.111) CLOCKRADIO

3 waveband radio alarm clock. Green display.

£19.95

LEXICON

LK3000

LL CON

LI Cl till U tJ IJ U GI

BOIS CI CI LI WSJ t.J

essaspeacacriacit

Rectiargeable power pack language translator forEnglish, Spanish, French, German. Italian andGreek.6 Language module included. £158.70

SINCLAIR

TEST GEAR 41111111111Mir

r,1111 Portable oscilloscope SC110

Frequency to 10 MHzSensitivity 50v-10mv per divisionTimebase from 0.1m secs to .5 secs perdivision. Weighs only llb 1 2oz.

£159.85 DFM 200

Resolution to .1HzSensitivity to 10mVRange 20Hz to 200MHz

DM 235 £52.95 DM 350 £74.00 DM 450 £107.00

SCOPES Elmac 4810 £143.70 5 meg 3106C £159.85

NEW! 15 meg 5810 5 CR £211.00

COMPUTER BOARD GAMESVoice Chess Challenger £229.90Chess Challenger 7 £88.00Computer Backgammon SAE for priceComputer Bridge £275.00

KRAMER & CO.Access Barchrycan1 Visa. Masterchage

9 October Place. Holders Hill RoadLondon NW4 1 EJ. Telex: 888941attn. Kramer k7. Tel: 01-203 2473

Mad cider only Callers by appointment

ETCH RESIST TRANSFERKIT SIZE 1:1Complete kit 13 sheets 6in x 4'hin£2.50 with all symbols for directapplication to P.C. board. Individualsheets 25p each. (1) Mixed Symbols (2)Lines 0.05 (3) Pads (4) Fish Plates andConnectors (5) 4 Lead and 3 Lead andPads (6) DILS (7) BENDS 90' and 130(8) 8-10-12 T.0.5. Cans (9) EdgeConnectors 0.15 (10) Edge Connectors0.1 (11) Lines 0.02 (12) Bends 0.02 (13)Quad in Line.

FRONT AND REAR PANELTRANSFER SIGNSAll standard symbols and wording. Over250 symbols, signs and words. Alsoavailable in reverse for perspex, etc.Choice of colours, red, blue, black, orwhite. Size of sheet 12in x 9in. Price £1.

GRAPHIC TRANSFERSWITH SPACERACCESSORIESAvailable also in reverse lettering, coloursred, blue, black or white. Each sheet12in. x 9in contains capitals, lower caseand numerals '/sin kit or '/4in kit. £1complete. State size.

All orders dispatched promptly.All post paid

Shop and Trade enquiries welcomeSpecial Transfers made to order

E. R. NICHOLLSP.C.B. TRANSFERS

DEPT. ETI 1

46 LOWFIELD ROADSTOCKPORT, CHES. 061-480 2179

CALCULATORSINCLUSIVE PRICES!!

TEXAS INSTRUMENTST125 Lc.d. scr/stats E19.95T142* 32 step prog. £41.95T144 L.c.d. sci /stets £19.95T145* slide rule functions £21.95T150 Lc.d. sci/stats £22.95T153 Lc.d. 32 step prog £24.95TI PROGRAMMER' £41.95TI5r 50 step prog £25.95T158* 480 step prog £64.95T158C above with prog retention £79.95T159' 960 step pog £169.95T158/59 ACCESSORESPC100C printer craJle £142.95MATH/UTILITIES Library £22.95MARINE NAVIGATION Library £22.95APPLIED STATS Library £22.95ELECTRICAL ENGINEERING Library . . £22.95LEISURE Library £32 95

Including adaptor/chargerELECTRONIC LEARNING AIDSLITTLE PROFESSOR £12.95DATAMAN £17.95SPELLING B £16.95CASIO MATH PET £19.95CASIOHQ21 L.c.d. with time £10.95A02000 L.c.d. alarm /stop/date £23.95MELODY 80 Lc.d. musical alarm £23.95FX310 L.c.d. 50 function sci £16.95FX5I0 Lc.d. 10 digit sci £18.95FX2600 L.c.d. 10 digit sci £18.95FX3200 L.c.d. 3100 update £20.95FX8000 L.c.d. above plus time E28.95FX5000 L.c.d. scientific E27.95FX5000EP Scientific printer £1 29.95FX202P Scientific E35.95FX50IP L.c.d. 128 step prog £46.95FX502P L.c.d. 256 step prog £64.95FA1 Adaptor to cassette for 501/502 £21.95OFFICE EQUIPMENTIBICO 10 digit print & display . . £87.95IBICO 12 digit print & display £99.95PHILIPS 0185 POCKET MEMO E59.95TELEPHONE ANSWERING MACHINES . CI 69.95ALL PRICES INCLUDING POST, PACKING & V A.T ®15%.Full range of TEXAS, CASIO and SHARP calculatorsandaccessories. plus PHILIPS dictation equipment suppliedat lowest prices

CALCULATOR SALES & SERVICEArrow Works, Arrow Road, Redditch B98111111

Tel. Redditch 10520 4,110u

108 ELECTRONICS TODAY INTERNATIONAL -- JANUARY 1980

1116. 1101116. Mk. NIL Nh. 111

Codespeed ElectronicsPO BOX 23. 34 SEAFIELD ROAD. COPNOR, PORTSMOUTH P03 5BJ

ELECTRONIC MAIL ORDER SPECIALISTS

New, Full Spec. Devices

LED WRISTWATCH I.C. Super value I C in 24 pin 'legless flatpack' style package for rneximurnspace saving iAiith data A snip at only 119p. Cat No. 208.0.1" LED WRISTWATCH DISPLAY. Also in a 'legless flatpack' style package. this displaymatches the wonwatch I C shown above. With data. Only 99p. Cat. No. 209.*erre CASH SAVER mete Purchase one each of catalogue numbers 208 AND 209 for only E1.50.POLARIZING FILTER MATERIAL 0.006" thick plastic film. Any size cut - even 1 sq. inch. Ma.width 19" any length. Only 2p per sq. inch. Cat. No. 701.BRIGHT ORANGE DISPLAY 9 digit. 7 segment gas discharge display. 0.25" high digits. WAhdata 75p. Cat No 310.OMM CHIP MM 5530 dvm chip. Builds into high accuracy dont or panel meter. Requires additionalorcurry Supplied with data and circuit. Only E3.95. Cat. No. 404.MINI B DIGIT LED DI 6 digit 7 segment display from Texas. Common cathode.multiplexed, with 0.1" digits E1 00. Cat No. 306.MM5314 CLOCK CHIP A super value digital dock chip for only £1.91. With data. Cm. No. 2074 DIGIT LCD A high contrast, easy to solder display with four 0.5" high non -multiplexed digits.E8.95 each with data Cat No 206DIGITAL ALRM CLOCK MODULE Complete with giant 0.84" LED display. Add transformer andswitches for complete clock. With data only E5.50. Cot. No. 205.GIANT LED DISPLAY Common cathode. non -multiplexed super 4 digit LED clock display. Lots ofother uses too Only E3.115 each. Cat. No 204.WRISTWATCH LCD's A high contrast 31/2 digit wnstvestch LCD with centre colon. Supplied withpolarizers and data. Only E1.00. Cat. No. 202MEMORIES MM2102 static 1024 bit commons. A snip et 1111p each Wtth data sheet. Cat. No10220 KEY KEYBOARDS Celculator keyboards. excellent key action. 20 keys per board. 2 keyboards

b. for E1.00. Cat. No 101.10 HYBRID CIRCUITS 8 resistors and 8 capacitors built into each hybrid circuit. Ideal values forsemiconductor circuits Excellent for minimizing PCB component space. 10 Hybrids for 110p. Cat No80125 germanium diodes 50p. 10 synching diodes 35p. Mini slider switches (2 pole change -over) lipeach. Momentary switches (spring loaded) with 1 n.a. contact lip each. Mono jack sockets 23peach. Stereo lack sockets 25p each. Slide control knobs (state colour) 12p each. Rotary control knobs(push -on). Black with coloured cap (state colour) 20p each

Untemel ItemsREJECT CALCULATORS Production line rejects. Yields lot of goodies when stripped down (notmuch wrong with some we tested) Only E2.50 each. Cat. No 104LED DISPLAYS (Untested - no guarantees) 10 seven segment LED displays 0 127" digitscommon cathode. 10 for E1.00. Cat. No 311.

4 CODESPEED'S DESIGN, DEVELOPMENT AND PRODUCTION TEAMS ARE ALSO ATYOUR SERVICE FOR QUANTITY/BATCH PRODUCTION.

Postage and Pocking please add 35p(Oversee. orders add 90p )

&nisi acnoo guaranteed or return for replacement or refundSend medium sized S.A.E. for your free copy of our new Autumn Catalogue (Issue No. 6)

Mi. II& NIL. IlL "ft. NIL

SOUTH WALESFOR TTL, CMOS, LINEARS, DIS-CRETES, PASSIVES, HARDWARE,TOOLS, CASES, TRANSFORMERS,ETC. CLOCKS, LEKTROKIT, BREAD-

BOARDING AND VERO DEALERSBOOKS BY NATIONAL, (OR, BABANI

SPECIAL OFFER FOR CHRISTMAS. ALL BRAND NEW. FULLSPEC.

DIL SOCKETS -GOLD PLATE8 pin 9p 24 pun 24p

14 pin 11p 28 pin 27p16 pin 12p 40 pin 32p18 pin 15.5p 4013 CMOS 24p22 pin 21p 7401 TTL 7.5pTHYRISTOR 1A, 200V MADE BY ITT, TYPE CRS1 /20AF 30p.BRIDGE RECTIFIER BY MOTOROLA 1.5a, 50v 28p.20 ohm LIN-POT BY AB (+1) 20p, (+ 10) 19p.100k LIN MOULDED TRACK (+1) 55p, ( + 10) 50p.RELAY 4 POLE C/O, 12v COIL, £1.00.20mm Q/B FUSES 150mA, 500mA, 4a, 5a, 50p for 10.GLASS ENCAPSULATED REED SWITCHES £1 for 10.DIGITAL METERS TYPE DM235 SINCLAIR MULTIMETER£58.PDM 35 SINCLAIR MULTIMETER £34.99.TFM 200 SINCLAIR FREQUENCY METER £53.TMK 500 £33 LT22 £15.10TMK 500 TUB £41 KRT 101 £7CASE FOR ABOVE £8ALL PRICES VAT INCLUSIVE PLEASE ADD 25p PACKAGE

AND POSTSEND YOUR ORDERS TO.

STEVE'S ELECTRONICS15/17 THE BALCONY, CASTLE ARCADECARDIFF, CF1 2BU TEL: (0222) 41905

OR VISIT US AT THE SHOP-OPEN TUESDAY TO SATURDAY 9-5.30 FRIDAY 12.30-7

Mail and Official Orders Accepted

Top of all systems

lasted by independentnational authority

July (9

C3001 ES200high performance electronic ignition,to add power,economy, reliability, sustained smooth peak perfor-mance, instant all weather starting, to your car.Surefire has sold in its thousands in ready made form from bigname accessory firms, but a is now available in quality kit form to fit allvehicles with coil ignition up to 8 cylinders.

ES200. A high performance inductive discharge ignition incorporatinga power integrated circuit (special selection): electronic variable dwellcircuit (maximises spark energy at all speeds): pulse processor(Overcomes contact breaker problems). Coil governor (protects coil).Long burn output. Negative earth only. Compatible with all rev. counters.

C300. In it's ready built form (C3000) it came top of all systems testedby an independent national authority July '79. A high energycapacitive discharge ignition incorporating a high output short circuitproof inverter, top grade Swedish output capacitor, pulse processorcircuit, transcient overload protection. Fast rise bidirectional outputideal for fuel injection, sports carburation, oily engines. Compatible withmost rev. counters. (Low cost adaptors available for rare cases.Application list enclosed with each kit. Note: Vehicles with Smiths/Jaeger rev. counters code RVI on dial will require adaptor type TCII.

What's in the kits. Surefire's own precision anodised aluminiumextruded case. P.C. mounted security changeover switch, statictiming light. Special selection Motorola semi -conductors. Capacitors,resistors etc. selected after 5 years experience. Glass fibre pcb,complete down to last washer.Fully illustrated comprehensive instructionsand full technical back up service.

Suretron Systems (UK) Ltd.Piccadilly Place, London Rd., Bath BA16PW. Tel: Bath 10225) 23194

Name

Address

Phone order with Access BarclaycardVAT and P b P Inc

Quantityrequired

ES200: Neg + £1M 111.95

C300: Pos - f 1,45- f 15.95

C300: Neg + f T.7-96. f 15.95

Tacho Adapt. TC1 £3.90

Dept. ETI 2

enclosechip PO's

Cho No

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 109

HobbyElectronics

How do we do it? Next month at great expenseto life, limb and sanity we hope to present you,the loyal readers, with an issue yet to besurpassed in the history of magazine publis-hing. Extravagant claims? We think not, justfeast your eyes on this little lot.

RADIO CONTROL

Do-it-yourself radio control systems always tendto be less attractive to build when confrontedwith hundreds of components, so for everyonethat has ever promised themselves a system HEproudly present a Multi -Function digital R / Csystem using the latest 'dedicated' state-of-the-art ICs in both the decoder and encoder tomake this system possibly the easiest andcheapest system yet published anywhere!

KIT REVIEW

Next month in conjunction with the RadioControl project we are reviewing a new servokit. This easy to build kit is ideal for use in ourproject car and will not leave you broke. Beforeyou start though it would be as well to armyourself with a fine -point soldering iron and anew pair of glasses as this kit calls for somepretty accurate soldering.

MINIATURE TV SUR-VEY

For people with very small eyes from peoplewith very small brains (no offence meant) wehave great pleasure in presenting this review ofall of the latest titchy tellies on sale at themoment, from the miniscule Sinclair to thesomewhat larger offerings from our Orientalcousins. We have drawn a limit at anythingexceeding a screen size of five inches, youwould be surprised what you can cram in such asmall box, one model combines a TV with aFM /AM radio cassette recorder. The kitchensink is an optional extra.

CMOS SPECIAL

Next month we present another in our verypopular series highlighting a particular com-ponent or device. This time it's the turn of theCMOS IC. As usual we show lots of practical,buildable circuits with the accent on the func-tional and novel side of our hobby.

CROSSHATCHGENERATOR

MINIE111111111111MENNEN=MINIM1111111=11111111111=11111111MI

To make this something of a TV special we havedecided to include in this month's projects oneof the most useful pieces of test gear availableto the TV engineer. It will produce a grid patternonto the screen of a TV set, this is particularlyuseful if you happen to be setting up theconvergence on a colour set or the picture sizeand shape on a black and white set.

If you're very clever it can also be used as aTV game, how does multi -layer noughts andcrosses sound?

SPACELABLook out for a major feature on one of theproposed payloads for the Shuttle. this neworbiting laboratory will enable scientists, ratherthan astronauts, to carry out their experimentsin a near -Earth environment.

DIGITAL DICEGroan, not another dice project, but wait, ourresearches have shown that dice projects areamongst the most popular electronic systems tobuild. Why? Simply because they are easy tobuild, ideal for a newcomer to electronics, easyto understand, and they work. They actually dosomething. Our project next month uses arather novel circuit that will be of interest tobeginners and 'old hands' alike

The January issue will be on sale December 14th14, 4-111,1 It'd 1,0,12 11Cli Uut C.III 11/11S1,111(.t, may dltuet the .1,tudi

1 1 0 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

8K ON BOARD MEMORY!5K RAM. 3K ROM or 4K RAM, 4K ROM (linkselectable). Kit supplied with 3K RAM, 3K ROM.System expandable for up to 32K memory.

2 KEYBOARDS!56 Key alphanumeric keyboard for entering high levellanguage plus 16 key Hex pad for easy entry ofmachine code.

GRAPHICS!64 character graphics option - includestransistor symbols! Only £18.20 extra!

MEMORY MAPPEDhigh resolution VDU circuitry using discreteTTL for extra flexibility. Has its own 2Kmemory to give 32 lines for 64 characters.

KANSAS CITYlow error rate tape interface.

2 MICROPROCESSORSZ80 the powerful CPU with 158 instruction, includingall 78 of the 8080, controls the MM 57109 numbercruncher. Functions include +, ", I, squares,roots, logs,sxponentigas, trig functions, inverses etc.Range 10-" to 9 x 19'' to 8 figures plus 2 exponentdigits.

EFFICIENT OPERATIONWhy waste valuable memory on sub routines fornumeric processing? The number cruncher handleseverything internally!

Cabinet size 19.0" X 15.7" x 3.3". Television by courtesy of Rumblelows Ltd., price f58.62

POWERTRAN

RESIDENT BASICwith extended mathematical capability. Only2K memory used but more powerful thanmost 8K Basics!

1K MONITORresident in EPROM.

SINGLE BOARD DESIGNEven keyboards and power supplycircuitry on the superb quality doublesided plated through -hole PCB.

COMPLETE KITNOW ONLY

£249 + VATKit also available as separate packs:e.g. PCB. Keyboards, Cabinet, etc.

PSI Comp 80. Z80 Based powerful scientific computerDesign as published in Wireless World, April -September,1979.

The kit for this outstandingly practical design by John Adams published in a series of articles in Wireless World really is complete!Included in the PSI COMP 80 scientific computer kit is a professionally finished cabinet, fibre -glass double sided, plated -through -hole printed circuit board. 2keyboards PCB mounted for ease of construction, IC sockets, high reliability metal oxide resistors, power supply using custom designed toroidal transformer. 2KBasic and 1K monitor in EPROMS and, of course, wire, nuts, bolts, etc.

PSI COMP 80 Memory Expansion Sys-tem

Expansion up to 32K all inside the computer's own cabinet!

By carefully thought out engineering a mother board with buffers and itsown power supply (powered by the computer's transformer) enables up to3 8K RAM or 8K ROM boards to be fitted neatly inside the computercabinet. Connections to the mother board from the main board expansionsocket is made via a ribbon cable.

Fibre glass double sided plated through holeP.C.B. 8.7" x 3.0" set of all componentsincluding all brackets, fixing parts and ribboncable with socket to connect to expansion plug

£39.90Fibre glass double sided plated through holeP.C.B. 5.6" x 4.8" £12.50Set of components including IC sockets, plugand socket but excluding RAMs . . . E11.202114L RAM (16 required) E5.00Complete set of board. components, 16 RAMS

E89.50

Mother board:

8K StaticRAM board

8KROM board

Fibre glass double sided plated through holeP.C.B. 5.6" x 4.8" £12.40Set of components including IC sockets, plugand socket but excluding ROMs . . £10.702708 ROM (8 required) £8.00Complete set of board, components. 8 ROMs

£78.50

Floppy Disk. PROM programmer and printer interface coming shortly!

Value Added Tax not included in pricesPRICE STABILITY: Order with confidence. Irrespective of any pricechanges we will honour all prices in this advertisement until February 28th.1980, if this month's advertisement is mentioned with your order. Errorsand VAT rate changes excluded.EXPORT ORDERS: No VAT. Postage charged at actual cost plus 50phandling and documentation.U.K. ORDERS: Subsequent to 15% surcharge for VAT'. No charge ismade for carriage 'Or current rate if changed.SECURICOR DELIVERY: For this optional service (U.K. mainland only!add 02.50 (VAT inclusive) per kit.

1431441111100/AP MN la

110111143111<i1114;;:,

111140 .174054i -

"-1.1040,40,111111 L'AgPAACtio,11111111111140 iliP'044P*31=3 RN MAP NI In

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$1111111111111111111111111111

UK Carriage FREE

POWERTRAN COMPUTERS(a division of POWERTRAN ELECTRONICS)

PORTWAY INDUSTRIAL ESTATE ANDOVERANDOVER HANTS SP10 3NM (0264) 64455

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 111

24 TUNE DOOR CHIMESDOOR TUNES E17.13 + VATWaddrigton's Videomaster announce a doorbell that doesn'tgo Brrringgg, Ding-Dong or Bum Instead it plays 24

different classical and popular tunes It will play the tuneyou select for your mood, the season or the visitor you areexpecting to call. Door nines is not only great fun andwonderful coi breaker. bin is also very functionally andbeautifully designed to enhance your home. There is

something for Chnsimas something for your continentalvisitors or your relations from the states, and evensomething for the Queen. Door tunes is easy to install andhas separate controls for volume, tone and tempo.

AROMA/MARBLE E211.50 + VAT.

COLOUR CARTRIDGE T.V. GAME.

The TV game can be compared to an audio cassette deckands programmed to play a muhrtude of different gamesin COLOUR, using various plugin cartridges. At long last aTV game is available which will keep pace with improvingtechnology by allowing you to extend your library of gameswith the purchase of additional cartridges as new gamesare developed Each canridge contains up to ten differentaction games and the first canndge containing ten sportsgames is included free %nth the console Other cartridgesare currently available to enable you to play such games asGrand Pnx Motor Racing. Super Wipeout and Shim Rider

Further canndges are to be released later this year,

induding Tank Bathe, Hunt the Sub and Target. The

console comes complete with two removable joystick

player controls to enable you to move in all lour directionslupidowninghtlleftl and built into these joystick controls areball serve and target lire buttons. Other features includeseveral difficulty option switches, automatic on screendonel scoring and colour coding on scores and batsLifelike sounds are transmitted through the TV's speaker,simulatmg the actual game being played.

Manufactured by Waddngton's Vineomaster and

guaranteed for one year

STAR CHESS - EWA + VAT.PLAY CHESS AGAINST YOUR PARTNER.

using your own TV to display the board and pieces. StarChess is a new absorbing game for two players which willinterest and excite all ages The inn plugs into the aerialsocket of your TV set and displays the board and pieces intoll colour for black and wheel on your IV screen. Based on

the moves of chess. It adds even more excitement andinterest to the game. For those who have never played.Star Chess is a novel introduction to the classic game ofchess For the experienced chess player, there are wholenew dimensions of unpredictability and chance added tothe strategy of the game. Not only can pieces be taken inconventional chess type moves, bin each piece can alsoexchange rocket lire with its opponents. The unit coniescomplete with a free 1BV mains adaptor, full instructionsand twelve months guarantee

CHESS CHALLENGER 'P-A EWES + VAT.PLAY CHESS mutest THE COMPUTER.

The stylish, compact, portable console can be set fa play atseven different levels of ability from beginner to expenincluding"Mate in two" and "Chess by mail" The computerwill only make responses which obey international chessrules Castling, on passant, and promoting a pawn are atincluded as pan al the computer's programme. It Is

possible to enter any given problem Irom magazines ornewspapers or alternatively establish your own board

position and watch the computer react The positions al allpieces can be verified by using the computer memory recall

MonPnce includes unit with wood grained housing, and

Staunton design chess pieces Computer plays Sack orwhite and against !sell and comes complete with a mansadaptor and 12 months guarantee

OTHER CHESS COMPUTERS IN OUR RANGE INCLUDE

CHESS CHAMPION -6 LEVELS E47.39 + VAT.CHESS CHALLENGER - 10 LEVELS - E138.70+ VAT.BORIS - MULTI -LEVEL TALKING DISPLAYE163.04 + VAT.

EXTRA CARTRIDGES.

ROAD RACE - 13.87 + VAT.Grand Prix motor racing with gear changes, cash noses

SUPER WIPEOUT - 131.17 VAT.

10 different games of blasting obstacles oft the screen

STUNT RIDER - L12.111 + VAT.Motorcycle speed vials, lumping obstacles, leaping variousrows of up to 24 buses etc.NON -PROGRAMMABLE TV GAMES

6 Gann - COLOURSCORE II - E13.50 + VAT.

10 Came COLOUR SPORTSWORLD 12250 + VAT.

ELECTRONIC CHESS BOARD TUTOR

E17.17 + VATA special bulk purchase of these amazing chess teachingmachines enables us to offer them at only 119 75 less thanhall recommended retail price. The electronic chess lUtOr 6

a simple battery operated machine that can actually teachanyone to play chess and improve !her game nght up tochamponship level. This machine is not only for total

beginners but also for established players wanting to playbener chess. Unit contains the electronic chessboard with32 chess Pieces. a 64 page explanatory booklet and a set of32 progressive programme cards including 6 beginners

cards, 16 check mate positions, 9 miniature games, 5openings, 3 end games, 28 chess problems and 2 mastergames

DRAUGHTS COMPUTERSCHECKER CHALLENGER 2 LEVELS E43.00 + VAT "rIGHTSCHECKERS AGAINST THE COMPUTER.

4 LEVELS 08.00 + VAT

The draughts computer er,t , -. ,

improve your game, and gfiry wfisnnver a want the

computer incorPbrates a sophisticated, reliable, decision

making microprocessor as as brain its high level of

'thinking ability enables a to respond with es best countermoves like a skilled human opponent You can select

offence or defence and change playing difficulty levels atany time Positions can be verified by computer °lemonrecall Machine does not permit Ilegal naves and can solveTor Problems Gurrilmer mutes complete with instructionsmains edema, and twelve months guarantee

FOR FREE BROCHURES - SEND S.A.EI.,' FREE Iflusiratea brochures and reviews (Ili TV and chess games please send a stamped addressed envelope, and state

which permute, gases you require intorniation on.

Callers welcome at our shop in Welling .denionsirations daily open from Darn 531.1pni Mon Sal lam 1pni Wert

to order by telephone please Quote your name, address and AccessBardaycard nunrherPostage and Packing FREE

AJD DIRECT SUPPLIES LIMITED, Dept. ET1 102 Bellegrove Road,Welling, Kent DA16 3QD. Tel: 01-303 9145 (Day) 01-850 8652 (Evenings)

112

AUDIOTEST

Telephone

ANDEQUIPMENT

your order with AccessCENTRE

RETAILMAIL ORDEREXPORT

ALL PRICESINCLUDE VAT

and Barclaycards '_ .

or send chequebe 2m, iCIO.cf t. --i .47

LONDON'SPEN 6

SCOPES - (UK PM' £1.50Flailing

with order.

iiiit-eilli .. O.,

TEST GEAR CENTREDAYS A WEEK 9 am -6 pm

ea.)170.00HM307 3 10MH, single beam

HM312 8 20MH, dual traceHM412 4 20M1 -le dual trace sweep delaySupers 10MHz single beamSuper 10 10MH, dual trace141315 Scope. 15MHz dual trace4025. Scope. 25MHz dual tracePROBES r 1.10 14.50 x 10 9.95. I 7.96SINCLAIR 10MHz MininscoOe

-

287.00402.50166.00239.00325.00414.00

559.55

t

FREQUENCYCOUNTERS

MAX 50 50mHz 6 digspocket counter 61.00MAX 100 100MHz 8 digitportable counts, 85.75MAX 550 550MHz 6 digit

DIGITAL MULTIMETERS0iA235 Sinclair portable 31/2 digit LEDPDM35 Sinn!. Pocket 31/2 digit LEDDM360 Sinclair 31/2 digit 1DM460 Sinclair 4'h digit with 10 amp

(30Kv Probes 19.00. Mains adaptors 4.00.M1200 Bench Portable 31/4 digit LED Resolution001 ohm .. . . .

935 Data Precision 3V5 dye hand-held LCD 2

52.9531.9074.45

range 106.45DM carry.. 8.951

1 v A / 01 my%. . .. 67.50

amp AC/ DC 113.85

pocket counter 106.00500 MHZ Prescaler for

I

max 50 or max 100 40.00PFM200 Sinclair 200MHzPocket Counter 8 digs 53.00OPT07000 7 digit. 600MHzrioncZes)HZ RES with

.

198. Low cost 31/4 digit general purpose LCD197. Pocket Low cost 31/4 digit LCD

52.9539.95

MULTI -METERS - GENERALMuloRange Instruments featuring AC/ DC volts.

except 71/ IT-2/712/TM3A (1M3TM11 incredible 120 Range Electronic MultiTM38 large scale .. .. AC MicroTM3A AC Micro360T11 100k1 volt 23 RangePROE 20k /volt 26 Range.7081 50k /volt 36 RangeTrnK500 30k/volt 22 Range68OR 20k /volt 52 Range7200 20k /volt 22 RangeMicro80 20k /volt 26 RangeRE132m /171-2 20k /soh 16 RangeLT22 204 /volt 19 RangeLT101 llovoh 12 RangeRE142m 20k /volt 17 RangeRE152m 20k /volt 19 RangeAT205 50k/1ml! 21 RangeTR202 20K /volt 23 Ranges/Transistor Checker

AVO Be and a large range

PURPOSE & ELECTRONICDC current Resistance Ranges an with mirror scales

AC volts only). some with AC current etcrneter . 158.00

voltmeter 3MHz >4 Meqohm 151.75voltmeter 3MHz>4 Magonin 139.50(plus transistor checker). Large scale 38.95Large scale 29.95

Multi -meter 22.95Multimeter (plus Continuity Buzzer) 22.95Pocket Multi -meter 36.75Double Multi -meter 17.95Pocket Multi -menu 19.10Popular M Jorneter 11.95Pocket Multi -meter 14.50Pocket Mulorneter 6.95Multi -meter 13.50Multi -meter plus transistor check 18.95Mulometer 28.95%Checker /Continuity Checker 19.95

of rept...mete tests leed in stock

GENERAL EQUIPMENT8E250 Signal InfectorTE7 Signal Tracer AF /RESWR50 SWR /Power Meter 19.503019. 6 Range Sound Level meter 21.55DC2SSV 100 Meg HV Probe 11.55DRE410 36 Value RM. Boa .

RP124 0/ 24v 0/1 Amp P/S StabilisedSingle Meter . . . . 42.00

RP230N 0/30,0/1 Amp P/S TyanMeters . .. .. 115.00

TR1000 Transistor checker in/a...circuit 11.95PA0063 Signal 'elector1.51 Transistor /Diode Checker . 21.503101 Clamp Meter 0 /1 K ohm 0/150%

300 /600 AC Volts O/300 Amp 3646SWRS SWR & FS Meter 10.50SWR10 SWR Meter 12.50MS319 2.100 Watt Audio Watt Meter 13.95'500V Megohmeter 500 Megohms 61.00'2 V, Amp Variable Transformer 21.95

5.159.95

3.55

6.65

GENERATORSTG152 Series 3Hz 300k Hz 5 RangesTG152D 86.25TG1520m (with meter) 107.50TG200 Seties RC Oscillators Sine 'Square output1Hr-1MHz 12 RangesTG200D 113.95TG2000m (with meter) 139.50TG200Dnes (meter & tine control) 145.904001 Digital Pulse Generator 0 51-17-5MHz

. 105.002001 Function Generator -Sine /SquareTriangle TTL 86.00SG2030 (13F16 bands 250101x-300MHz 49.95AG751 rAudrol sere 19Hz-220Hz square 1 9Hz-100KHz 61.00ARF300 (RE -Audio) 18h1,200M11, 78.50

PROTO BOARD IN STOCKKITS PR 6 9.20, PR 100 11.80.SEPARATES EXP300 5.76, EXP5006.30.0T 7B 1.30, EXP4B 2.30.

DRILLS AND DRILL KITS9 end 12 volt Operated 1/4" max.SMALL DRILL with colletsMEDIUM DRILL with 3 colletsSMALL DRILL with 20 drills, etc 16.95SMALL DRILL with 6 P/C drills 12.95MEDIUM DRILL with 20 drills, etc 18.95MAINS Eliminators 5,VARIABLE Speed 5 13.9512 volt 1/4" Heavy Duty Drill 12.50

6.859.90

9.95

LOGIC PROBES ANDMONITORS

LT2000 Economy Probe 10MHz 11.96LM1 Monitor .33.00LP1 Probe 10MHr 35.50LP2 1 5MHz 20.5015 -pin IC test clip 1.95

PIEZO HORNA TWEETERS/- ,..- , Uo to 100 its each No x.over

I 141 reqd. Only 4.95 ea_, Rated Horns 6.50If Midrange Hared Horns 11.95

,P P 20p tier 1 or 2 30p oer 3 to 5)

TV SOUNDHigh quality TV sound from your Hi.F1Simply plug trio aerial socket of yourtuner. 6.50 (UK P&P 50p)As reviewed b 'Po ular H i-Fi '. July '7

FM

9

SPECIAL OFFER

GEC 1E1.10 well Tomr/Areplitier.WM/SW/Stem FR Seopliedas hoe easy to commands.

1:24.115 P&P E Iate

- 4 , , WE SELLKel. Seas. Audax. Fane. TM3

6-43.4..1

TM 1 1

>/

TMK500

Goodmans. MotorolaPeerless

Speakers/Kits. etc.em.

CALL IN AND SEE FOR YOURSELFPRICES

AU301

01-724-3564.

CORRECT

EDGWARE

1 IDAT 1.11.79

ELECTRONICSRD.,

OPEN

LONDON

9-6,W2

MON-SAT.

TREECATALOGUE

1BN SENDr STAMPEDitro UZIADDRESSED ENMELOPE

iMIN 9' i x 6 i l

COPY NOWFon YOURALSO AT 248 TOTTENHAM COURT ROAD W 1

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

Now, the complete MK 14 micro -computersystem from Science of Cambridge

VDU MODULE. £33.75(£26.85 without character generator) inc. p & p.

Displa up to K memory 32 lines x16chars, with character generator, or 4096spot positions in graphics mode on UHFdomestic TV. Eurocard-sized module include,UHF modulator, runs on single 5 V supply.Complete ascii upper-case character set can bemixed with graphics.

POWER SUPPLY. £6.10 inc. p & p.Delivers 8 V at WO mA from 220/240 V mains -sufficient to drive all modules shown heresimultaneously. Sealed plastic case, BS -approved.

MK 14 MICROCOMPUTER KIT£46.55 inc. p & p.

ed microcomputer kit withhexadecimal keyboard, display, 8 x 512 -bytePROM, 256 -byte RAM, and optional16 -lines I/O plus further 128 bytes of RAM.

Supplied with free manual to coveroperations of all types - from games tobasic maths to electronics design. Manualcontains programs plus instructions forcreating valuable personal programs. Alsoa superb education and training aid - anideal introduction to computer technology.

Designed for fast, easy assembly; supplieowith step-by-step instructions.

Science ofCambridge Ltd6 Kings Parade, Cambridge, CAMBS., CB2 1SN.Tel: 0223 311488.

CASSETTE INTERFACE MODULE.£7.25, inc. p & pr.Store and retrieve programs on any cassetterecorder. Use for serial transmission dun nsingle line at up to 110 baud . teletype speed ,e.g. over telephone line, and to COMMUlliC atebetween two or more MK 14s.

PROM PROGRAMMER.£11.85 inc. p & p.Use to transfer your own program developedand debugged on the MK 14 RAM to PROM 74S571! to replace SOPS monitor forspecial applications, e.g. model railwaycontrol. Software allows editing and verifying

To order, complete coupon and post to Science of CambridgeReturn as received within 14 days for full money refund if not completely satisfied.

171n: Science of Cambridge Ltd, 6 Kings Parade, Cambridge, Cambs., CB2 1SN.

Please send me: MK 14 standard kit a L46.55. Extra RAM ii L;4.14 per pair. RAM I/O device a £8.97. VDU module including character

generator o £33.75.

Cassette interface module PROM programmer it £11.85. Power supply it Full technical details of the MK 14

System, with order form.All prices include p+p and VAT.

I enclose cheque/MO/PO for 'total .

Name

Address please print

1

ET11/8rj

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

- CLEF KITS -

High Quality Electronic Musical In-struments under the personal supervi-sion of Specialist Designer A. J.BOOTH MAN.JOANNA 72 & 88 PIANOSSix and 71/4 Octave Electronic Pianos withunique Touch Sensitive Action as used inthe P E JOANNA, which electronicallysimulates piano key inertia - a featurenot available in any other design. Buildthis widely acclaimed professional instru-ment, for either Domestic or Stage use,horn our top quality Compinent.kits.SIX OCTAVES -£18471/4 OCTAVES - £209P.E. STRING ENSEMBLEThe versatile String Synthesizer with afantastic sound at an economic price. SplitKeyboard facility with a range of impress-ive voices

COMPKNENT KIT - £164Back up TELEPHONE advice is avail-able from the designer to supplementthe clear instructions included withthe above Kits.P.A.'s - SPEAKERS -CABINETSUnits can be supplied to add to theComponent Kits, including Domestic orStage Cabinets and portable tubular legs.

SUB -KITSReduce the cash outlay during thebuilding process - details in the lists.

KEYBOARDSWe believe that we have located the bestmanufacturer of square front Keyboards.as used in our Kts, and can also supplyKeyswitch hardware including the in-dustry standard soft plated contactsprings.49 NOTE C -C £23.8073 NOTE F -F £37.0088 NOTE A -C £45.00All Keyboards are easily cut to provideyour required length and compass. Quan-tity enquiries welcome.

NEW KITSThis space reserved for December releaseof Electronic Rotor! (See us at BREAD-BOARD '79).

BUILDING SERVICEWe are specialists in Electronic PianoManufacture and can build your Piano foryou - see lists.

DEMONSTRATION CASS-ETTESPlease specify Ensemble or Piano at£1.50 each for ten minute content. Costmay be deducted from subsequent orders

INFORMATIONPlease send S.A.E. quoting items ofinterest. Telephone BARCLAYCARDorders can be accepted, all prices includeV A.T.. carriage & Insurance.

VISITSAre welcome by appointment, otherwiseMal Order Only.

EXPORTEnquiries welcome - in Australia pleasecontact JAYCAR (Sydney)

CLEF PRODUCTS (ELECTRONICS) LIMITED(EDT)

16 Mayfield Road, Bramhall, Cheshire SK 7 1JU. 061 439 3297

DISPLAY LIGHTING KITS

Each unit has 4 channels (rated at 1KW at 240Vper channel) which switch lamps to providesequencing effects, controlled manually or by anoptional opto isolated audio input

OLIO:WICThis kit features a bi.directional sequence. speedof sequence and frequencyof direction change being

enable by means of poten-).0meters Incorporatesmaster dimming control

E14.60

01210008lower cost version of the

featuring unidirec-al channel sequence

In speed variable b1'leaf. of a preset pot. Out.nuts switched only at mainszero crossing points toreduce radio interference tominimum £8.00Optional Opto Input (DIA 11

601s.

MINI KITSThese KITS form useful subsystems which may beincorporated into larger designs or used aloneKITS include PCB. short instructions and allcomponentsTEMPERATURE CONTROLLER/THERMOSTAT. Uses LM 3911 IC to sensetemperature (80 C max ) and mac to switchheater 500W E3.20 1 KW £3.50SOLID STATE RELAY, Ideal for switchingmotors lights, heaters. etc.. from login. Optoisolated with zero voltageswitching SuppliedWITHOUT mac Select the requiredMac from ourrange E2.60BAR /DOT DISPLAY. Displays an analoguevoltage on a linear 10 -element LED display as a baror single dot Ideal for thermometers. level,indicators etc. May be stacked to obtain 20 to'100 element displays Requires 5-20V supply.

E4.75

TRIACS400V Plastic Case (Texas)

3A 4141 16A8A 579 20A

12A 71Ip 25A6A with triggerBA Isolated tabDili

90p165p190p80p82p18p

DIGITAL VOLTMETER/THERMOMETER KIT

£20.75

sed on r e ICL 710This kit contains a PCBresistors, presets, capacitors, diodes, IC and 0 5"liquid crystal display.Commies in IS. lecleHtl toNON On basic 05 kii io be

111811111 be I 04831 Thernomeitr

nisi I Pape lees Is as Nato,Rapist a 341 AI Supply IPP3SI

LEDs DISPLAYSO D.1".119119NJ 0.2". Ad Sp

or. fens 12ptr. Mrs 12pHun Rel.5112.50199 alp

SPECIAL OFFER25 off 0 2"Red E1.50Green E2.00 e SPECIAL a 1174 Opto IsolaYellow £2.00 tor 45p

ocry 05"

f_150

OL304 les menial MB et 704)03" 70p01.841/015500. csegabbii kithD1.747/75(110.r Dub E1.90

INTEGRATED CIRCUITS555 Timer 21p741 Op Amp 18pAY -5-1244 Clock £2.60

AY -5-1230 dock /Timer E4.50AY -5-1232 Clock z Timer £4.50ICL7106 D.V.M.(LCD Clove) E7.00TDA1024 Zero Voltage Switch £1.20LM10C OP Map

,

£2.99LM3911Thermometer E TOLM386 250mW Audio Amp 75pLM380 2w Audio Amp 90pLM382 Lo noise pre -amp E1.001M377 duel 2w Audio Amp E1.45LM379 dual Audio Amp £3.50TBA 800 5w Audio Amp E6OpTBA 810 7w Audio Amp

0LM1830 Fluid detector E111,1LM2907 Frequency S to V converter E1.5511.43909 LED Flasher . . . 76pMM74C915 7 sag to BCD convener . SepMM74C911 4 digit display controller E4.50MM74C926 4 decade counter E4.50LM7217 Dot/ Bar dnver E2.40ICM7217 Counter IC .A LED Drive) E7.90MM57610 . . 110pMM57160 Stec Timer E5.95S5668 Touchdimmer E2.6059268 Touchdirniner £4.852N1034E Timer El .80

II IC's supplied with data and cu , coooni 5

ALL COMPONENTS ARE BRAND NEW AND TO MANUFACTURERSSPECIFICATION. ADD VAT AT CURRENT RATE TO ABOVE PRICES PLUS 30pP&P. MAIL ORDER - CALLERS WELCOME BY APPOINTMENT.

EITK Electronics LONDON.E71106

SW7117 21.01xETTGERLA0P1185E1R909A7834

111111110P1116,

* * * *

OUTSTANDINGFEATURES:DUAL TIME: Local timealways visible and youcan set and recall anyother time zone %such asGMT). Also has a light fornight viewingCALENDAR FUNC-TIONS include the dateand. day in each time

'zoneCHRONOGRAPH/STOPWATCH displaysup to 12 hours. 59minutes. 59 9 seconds.

MEN'S FIVEFUNCTION

QUARTZ LCDHours. mins secs.,month., date, auto.calendar. Quality metalbracelet 8mm thick.

£6.95

* * * * *

* * * * * * * * * * * *

MEN'SSLIML1NE 7mm

SOLAR DUALTIME ALARMCHRONO WITH

MINERALGLASS £33.95

LADY'S

7 -FUNCTION

ALARM

'On command stopwatchdisplay freezes to show *intemtediete (split/lap)time while stopwatch .rcontinues to run. Can also A,switch to and from -timekeeping and stop- *watch modes withoutaffecting either s opera- *bon.ALARM can be set toany time within a 24 -hour 4period At the designatedtime. a pleasant, but*effective buzzer sounds toremind or awaken you!

Ladies' 7 -function Alarm,MM . sec.. hr. Day, date,month. backlight, 8mmthick.

£14.95Inc. VAT & P&P

MEN'S7 -FUNCTION

ALARM WATCHAlarm. Hours, mins.,secs. Month, date, day, 6digits, 3 flags, plus con-tinuous display of dayand date or seconds.Bak -light. 10mm thick.

£11.95Inc VAT & P&P

* * * * * * * * * * * * * * * * * * * * * * * *

ILLITRCNIICS IL1ID12 Little Newport StreetLondon WC2 7- 1- 1 (orPh_) !437 4910

LADY'S

5 -FUNCTION

WATCH *Gold/silver colour finish.*8mm thick.

£12.95Inc VAT & P&P

* * * * * * * * * *

* * * *

MEN'S ALARMCHRONO

--7=.

LADY'S

5 -FUNCTION

WATCHHours. mins., sec cbymonth, date. backlight8mm thick.

£9.95Inc VAT & P&P

* * * * * * * * * *

Hr min., sec., day, date, *1 10 chronograph, laptime, alarm. 6 digits plus *day, 12/24 hour option.Month date/date month *option.10 mm thick.

Inc. VAT & P&P

* * * * * * * *

£18.95

* *

MEN'S

11 -FUNCTION6 digit. 11 functions.Hours, mins., secs., day.data, day of week. 1 /100th, 1 / 10th. secs.,10X secs., wins Splitand lap modes. Back-light, auto calendar. Only8mm thick. Stainlesssteel bracelet and back.Adjustable bracelet.8mm thick.

£10.95Inc VAT & P&P

* * * * * * * *Payment can be made by sending cheque or postal order Write your name and addressand order details clearly. All products carry one year guarantee and full money back10 -day reassurance. Battery fitting service is available at our shops. All goods are sent byfirst-class post.

8.CLAVCARD

tShop open 7 days per week, 12 noon to 8 p.m.

114 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

FINDINGIT HARDTO GET?

Do you suffer from ETI withdrawal symptoms?

Do you break out in a cold sweat every month, wondering where your next ETI's coming from?

Do you nave holes in your socks?

The answers to these and many other vital questions of today can be found in ETI subscriptions.

For only £7.00 (£8.00 overseas) you can have twelve issues of ETI (all different) and cunningly

spread over the entire year. You'll never again have to pack sandwiches, don haversack and set

out on a monthly treck around the newsagents.

Relax in your armchair and wait for the satisfying sound of the best electronics mag in the

country (unbiased opinion) dropping onto your welcome mat, delivered by hand to your door.

Send your subscription fee direct to ETI SubscriptionsMap PublicationsPO Box 35Bridge StreetHemel HempsteadHerts.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 115

PCB FOIL PATTERNS

fifil:44....++;

OD c

4i)NuieN)ETI BUFFER

Herein this months PCB patterns (minus the DFMwhich is double sided and copyright Watford). Alsoshown are the two we missed from last issue,namely the hum filter and logic probe.

1 1 6 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

PCB Foil Patterns

Left: process controller board.

Right: last months logic probePCB. Apologies for the delay!

Below: the Triton EPROM pro-grammer PCB. Companies noteTransam hold copyright.

ETI TRITON EPROM PROGRAMMER

1

1-1.(J )ugaTITTTIT

"("\*

( J7117 1114.144"411)%. _]L.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 117

CLASSIFIED INFORMATIONSemi -Display: -1 -3 insertions - £6.00 per single column centimetre4-11 insertions - £5.50 per s.c.c.

12 insertions - £5.00 per s.c.c.Classified: -23 pence per word (minimum 25 words)

Box number £1.00 extra

ALL ADVERTISEMENTS IN THIS SECTION MUST BEPRE -PAIDClosing date: 1st Friday in month preceding publication.

Advertisements are accepted subject to the terms and conditionsprinted on the advertisement rate card (available on request).

Cheques and postal orders should be crossed and made payable to'Electronics Today International.'

CLASSIFIED ADS, E.T.I., 145 CHARING CROSS ROAD,LONDON WC2H OEE. (TEL: 01-437 1002).

VIDEOMUSIC

VI 135001.45.......= os.....oa co.c

.61,1.1 (Ty/MT SV.S.VVJAS

Videograph II links to the aerial socket ofyour tv and provides a full colour GIANToscilloscope display. A must for hi-fi, homeentertainment, discos, organs etc.New - signal invert control, integral square wavegenerator. Plus - full details for testing your audiosystem for transient dist.ortion, crosstalk etc.Complete ryLuxu cabinet andKit only £26.95 controls. £12.95

READY BUILT UNIT E49.95 Et .00 P&P

WILLIAM isowerPou.. 8iIlaray RoadSTUART '4°,0-,7r,,ri,-,770- mrt

SYSTEMS Ltd Telephone Brentwood (0277) 810244

STEPPING MOTOR DRIVES: 0.5 amps/phase, £17. 4 amps/phase, £21. Motors16oz. in., £15. Send for details: R. Harden,24 Belvoir Avenue, Trentham, Stoke-on-Trent.

TRANSCENDENT 2000 SYNTHESIZER.No waiting! To buy a fully working instru-ment. Come and try for yourself. £250 ono.Twickenham, Middx. 892-7943 (evenings).

PRINTEDCIRCUITS

HARDWARE

Comprehensive range Constructors HardwaJ,and accessories.

Selected range of popular components'Full range of HE printed circuit boardsnormally ex -stock. same day despatch atcompetitive pricesP C Boards to individual designsResist -coated epoxy glass laminate for thed i y man with full processing instructions (no.unusual chemicals required)

Alfac range of etch resist transfers and otherdrawing materials for p c boards.

Send 15p for catalogue.

RAMAR CONSTRUCTORSERVICES

MASONS ROADSTRATFORD-ON-AVONWARWICKS. Tel. 4879

CONVERT YOUR CAR TO GAS. Sur-prisingly easy. All parts readily available (plusfree DIY fuel plan). £1. B. Kerr, 27 ColesRoad, Milton, Cambridge CB4 4BL.

IN -CIRCUIT TRANSISTOR TESTERS.Also tests out of circuit transistors, thyristors& diodes. £7.95 post free. Sae list. Bobker,29 Chadderton Drive, Unsworth, Bury,Lancs.

WANTED: ELECTRONIC COM-PONENTS, Redundant Stock, Test Equip-ment, Tools, Machines, Hardware; Factoriescleared. Immediate cash decision. Contact:Mr. Quirk, "Q" Services Electronic (Camber-ley) Ltd., 29 Lawford Crescent, Yateley871048, Camberley, Surrey.

Electronic kits for the thrifty!Build 50 Interesting Projects on a P.C. Chassis withsurplus components from your "Spares -Box."

EXPERIMENTER'SPRINTED CIRCUIT KIT

Contents: 4 small boards to suit the enclosed designs.Etching Powder, Resist Paint Solvent, Degreaser and,Etching Instructions; also 50 Circuit diagrams, ChassisPlans and Layouts for simple Crystal Sets, TransistorRadios, Transmitters, Amplifiers, Intercoms., RadioControl, Metal Detector, Photoelectric and UltrasonicAlarms, "Perpetual Motions", Light -Beam TelephoneInstruments, Testers, Gadgets, etc., you can build atnegligible cost with "Surplus" or reclaimed parts andtransistors you already have.Pricc.E.1.70. Postage and Packing 30p.

PHOTOELECTRIC KITA kit of basic parts to build a simple I.R.-sensitivePhotoelectric Switch. Contents: Phototransistor, Tran-sistors, Diode, Resistors, Connector. latching Relay,Chassis Board, Case. Screws and full instructions.Price, E4.50. Postage and Packing 50p.

OPTICAL KITA kit of parts to build an I.R. folded -beam Projector andReceiver to Suit the above kit. Contents: 2 Lenses, 2Mirrors, 2 45 -deg. blocks, Infra -Red Filter, Lampholder,Building Plans. Price: £3.70. Postage and Packing 30p.Both kits together make an Invisible -Beam Alarm.

EXPERIMENTAL ELECTRONICS335 Battersea Park Road, London SW11 4SL

Send SAE for full details of all kits and circuits

TGS GAS SENSORS 812 & 813. Sendaddressed envelope 61/2" x 9" for Tech.Data and Prices. Design service alsoavailable. Asti Supplies Ltd., Shannon,Co. Clare, Ireland

_ PAP -QUALITY ELECTRONIC

COM PONENTSAT LOW PRICES

Write or telephone for free pamphlet to.

HARRISON BROS.Dept. E.T.I., P.O. Box 55

Westcliff-on-Ses, Essex 550 7LQTelephone. Southend-on-Sea 32338

Mau wad

ORGANISE YOUR COMPONENTS!

COMTRAYSStore resistors. capacitors, IC's, screws, etc. Ideal fororganising your project components - saves all thatsearching around while constructing. Plastic trays with16 compartments, each compartment 3'4 x 216 x1'/x ins. deep.

-11.90 each,,inclitding p.p. and VATFour for £6.95 (64 compartments)

Eight for £12.60 (126 compartments)

.Cheque or P.O. to:

HELISTAR SYSTEMS LTD.150 WESTON ROAD

ASTON CLINTONAYLESBURY, BUCKS HP22 5EP

Tel. Aylesbury 630364

OLIVETTI TE300 ASR 10 CPS (Paper TapePunch/Reader included) Terminal for sale.Full working condition. £300. Telephone995 8038 (day) or 749 2750 (evgs.).

BREAKING COMPUTERS. All parts avail-able. Callers only. E. R. Nicholls, P.C.B.Transfers, 46 Lowfield Road, Stockport,Cheshire. Tel: 061-480 2179.

CCCATMYE

R£114.99

+pPt/P £3.45Optional extra manualC6 Total £124.44 A

BEST OFFER EVERCamera Kit, Lens,Vidicon Er Modulator

CROFTONTel: 01-8911923 detFor als

full

118 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

,Available for most ETIprojects from day one of

ETI, 'phone your order.

SPECIAL OFFER-Singlesided Pax PCB mat, four off,:43/4",x 61/2'L,99pall up

35 GROSVENOR ROAD, TWICKENHAMMIDDLESEX TW1 4AD Tel: 01-891 1923

FLASHING RED LEDS 89p.Small Reed Switches 10p. Magnets 7p.Rubber Mats 11p. Syringes 16p. Postage18p.

GRIMSBY ELECTRONICCOMPONENTS

Lambert Road, GrimsbyHumberside.

List 12p

MSF CLOCKSNEWT Shows continuous Date, Hours. Minutes,Seconds, 8 digit LED - larger digits for Hours andMinutes, also parallel BCD output, never gains or loses,auto -reset after power failure, auto GMT/ BST and leapyear, only 5x8x15cm, built-in antenna, 1,000km range.IDEAL for synchronising activities, navigation, astro-nomy etc. ABSOLUTE TIME always. FAILS°.60KHz Receiver, serial data output, £13.70.V.L.F.? EXPLORE 10-150KHz, Receiver £10.70.Each fun -to -build kit includes all parts, printed circuit,case, instructions, postage etc, money back assuranceso SEND of/ NOW.

CAMBRIDGE KITS45 (TA) Old School Lane, Milton, Cambridge

INTENSIVE WEEKENDCOURSES IN

BASICincluding hands-on mini com-

puter operation.This short intensive course is intended toinstruct from minimal knowledge to anoperational capability of computer pro-gramming in BASIC high level language. -The course is fully residential front Fridayevening to Sunday afternoon.Option of non-residential weekend, week-day evening and weekday courses avail-able if required.

For further details of dates available,fees, etc..

Phone (0401) 43139, or write toDept. ETI

CLEVELAND BUSINESS SERVICESCleveland House, ROUTH

Beverley, North Humberside

Inner London Education AuthorityLondon College of FurnitureDEPARTMENT OF MUSICAL INSTRUMENTTECHNOLOGY (ELECTRONICS)LECTURER GRADE I - is required as soon as possible toteeth electronics to Technician Education Council (T.E.C.)Diploma level in subjects related to electronic musicalinstruments and audio frequency engineering.The person appointed should have a C. & G. Final or H.N.C./H.N.D. in Electronics and a practical knowledge of electronicmusk systems.Salary:On an incremental scale within the range of E3,480E5,988plus supplement of £6 per month, subject to formal approval(plus 0174 Inner London Allowance), starting point dependingon qualifications, training and experience.Application form and further details available from: SeniorAdministrative Mks, LONDON COLLEGE OF FURNITURE,41.71 Commercial Road, London, El ILA. Tel. No. 91-247 1953.

THE UNIVERSITY OF SUSSEXSCHOOL OF MOLECULAR SCIENCES

ELECTRONICSTECHNICIAN

GRADE 4Required as soon as possible for the digital systemslaboratory, this new post will give an excellent oppor-tunity to a suitable candidate to. join a small groupworking in a busy research environment. Duties toinclude development and servicing, under supervision,of computer -based equipment for research and teachingpurposes. The main requirement is a keen interest inmicroprocessors and digital electronics, but candidatesshould possess a good working knowledge of moderndigital electronic design and construction, and prefer-ably an ONC or equivalent.

Salary on scale E3,432 -E3,950 p.a. rising on 1st April,1980 to £3,641-E4.191 p.a.; both salary scales aresubject to review. Twenty days' annual holiday plusUniversity closures and Bank Holidays.

AppficatIons in writing and enclosing the names oftwo technical referees to Mr. P. J. Gilliver, Super-intendent of Laboratories, School of MolecularSciences, University of Sussex, Fahner, BrightonBN1 9ELI.

BARGAINS FOR THEELECTRONIC HANDYMANBRANDED LED DIGITAL

ALARM CLOCKS

mg(1) (2) (3)

Returned to Service Department within guaranteeperiod.It With alarm repeat - S.R.S.P. of El 7.00 offered at

E3.95 inc. VAT.(2) With luxury lamp and repeat alarm as featured in

Most major U.K. Mail Order catalogues, S.R.S.P.£31.00-offered at E7.95 inc. V.A.T.

(3) With integral luxury light and repeat alarm also asfeatured in most major U.K. Mail Order catalogues,S.R:S.P. of £32.00-offered at ,0,46 inc. V.A.T.

-

These will be sow as received from our customers withthe existing fault(s) and without guarantee.

Discounts available on large bulk purchases

PRESCOTT CLOCK ANDWATCH COMPANY LIMITED -

Prescott House, Humber Road, London NW2 6ER

TEKTRONIX dual beam oscilloscope, TypeS81, for sale. Full working order with allfacilities. £150 ono. Tel. Wokingham784966.

STOP PRESS: Superboard Compatible/

COLOUR

YOUR

NASCOM!DAllLING COLOUR GRAPHICS FOR NASCOM 1

Genuine bit -addressable "pixel" system for straightforward programming of pictorial or mathematicalfunctions.

8 Colour display plus 8 colour independent backgroundfacility. Full documentation with FREE SOFTWARE:powerful sub -routines for vector generation, demon-stration program for animated effects. All runs in Nascom1 without expansion. Complete with UHF ColourModulator for operation with normal colour TV set.Superior design allows connection to most other micro-processor systems - send us diagrams etc of your b Et wvideo circuitry for free advice. Don't be fooled by theprice: this is a top quality product which will transformyour computer.

NOW AVAILABLE FOR0C4 of VAT

LIMITED PERIOD AT ,ostage

WILLIAMDower Ho se Bilioriody Road. corm.Elise;e7 gcamtei.31330si woodSTUART Ey.

SYSTEMS Ltd Telephone Brentwood 0271110244

If it's a case of making your projectlook good, then use one of ours.Simply send a S.A.E. forDetails and prices.

TRADE ENQUIRIESINVITED. 1,663.! (

H.M. ELECTRONICS271a/275a Fulwood Road,

BroomhillSheffield S10 3BD

"VERO 19" CARD FRAMESHeight 5U. Super value. Suit Newbear 77-68Price includes cabinet, frame, module. blankplates, etc. £15 + £4 p.p. 78 way edge conns£1 each. Regulator PCB £4.Tel. 04895-5355 (Southampton) anytime

LEDs flee Gre Yell125in 10p 16p lapTB Ilk 16e IseIntend MW 0.55

Couple 11 74 55pLED DISKATS707 34, DI 900747 6ffl DI 170p

ORP 12 Ler 62p0001 Photo tr 40p19125 1513p

photo tel 50p

AC125/6/7/8 I Bp

11117 27p11124/5/6/7 35pAF139/239 411p

BC/10711/9 9p01/107/8/90 10p6E147/8/9 7p66157/8/9 lap11167/8/9 tiplICINJE 12p116177/8/9 14p11116/3/45 10p0E186/7 24pBC12/3/41 10p61070/71/72 14p10131032 35p50139,140 35p61194/5/07 100BFR39/46 27p81179/0 27p65150,51 15p8552314/85 25p83119/20 top1812955 £1

14.113055 68p10S105/06 22p100155/56 22p0071 17p111144:30A Sprim A/32A 45p10411/428 50p

11P35/36,11 £228697 12p211706 'IP251711

221.

2112219 Op242904, 5,6 7 200

2112934 558 22p211292681 9p2112925111 I I p7113053 16p213054:3055 45p203792'3A Ilp2113773 E3

2113901/4/5/6 lip2112646 48p11643UJT rup85244 32pMPF102 32p21111319 20p

2713823 65p205245 45p205657.8/9 32p2115027 34p1914/4148 3p0916 5p04001/2 up4480/4 6p144005/6 7p114007 Bp

34 Plastic 50V 12p0011 14p 5308 16p

4001 199 5001 24p010006 22p

WORM I IP64/06 011

81127 12p0447/70/0895 Op

5890/91,L,I'5879/5881'"1

00280/5/202 BP

V PEGS IA plastic 5V128 15V IR 24V pas

650 mil ISp100.01092 .4. to

m mly 34ptoss llestalit20V 100mA E2723 D1L14 44p709 all 28p741 8 pin 113p

748 0 11_ 3Sp74714 -pm DI L 50p1M301 705 25pLM308 DIL13 90pLM3900 OIL 14 65pCA 31 30 90pCA 3140 80p555 T.mer 22p5562m555 60pLM380 80pLM38 1 140pTBA BOO OIL 70pCA3046 Away 75pNE565 130pNE566 veo 135p2X414 85pBRIDGES

1A 2A 10150V 22p 35p 150p100 25p 40p200 28p 45 p 170p400 34, 50pPCB Pen 110pInsulation kitsT03,66'220 5pLED Chips 3p

8 C R 50V 100V 400V DILSOCKETS Eon 10p ZENERST05 IA 28p 32p 40p 14pin 11p 16pin 12p 2 7-33V1066 3A 32p 34p 48p 1 Bpin lap 2Cpon 20p 400mW 9pSTUD 7A 54p 58p 70p 22pin 22p 24pn 25p 1 3W 16pTroac 400V 2A 70p 10A El 28pin 30p 40pon 35p Din 20pISLAND DEVICES, 9PAAPLESTEAD, PARK STPrices inclusive Post & Pack 20p ALBANS, HERTS

.

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 119.

DO YOU TRANSMITAUDIO SIGNALS

OVER CABLECIRCUITS?

We manufacture a full range ofinterface equipment for transmis-sion of audio signals over privatewire of telephone circuits, fromNarrow Band STD systems(300Hz-3.4kHz) up to Wide BandMusic Circuits.

PARTRIDGEELECTRONICS

(A. C. Partridge Ltd.)56 Fleet Road, Benfleet, Essex

Tel: (STD 03745) 3256We also manufacture audio

mixers and sub -assemblies

DIGITAL CAPACITANCEMETER

1pF to 2pF in 5 ranges. Directreadout in pF. nF and 0F Accu-racy 0.5%.Assembled modules £22.92 allinc.Precision Measurements P.O.Box 70, St. Stephens Ct.. Can-terbury Kent (prototype shownon photo).

CIRCUIT DESIGN, Prototype construction,1Analogue or Digital, Single Circuits or Corn-plete Instruments/Systems. Write A. J:ATTWOOD, C.Eng., MIERE, Heathercote,Heatherton Park, Taunton, Somerset, TA41ET or Phone Bradford -on -Tone (082-346)536.

BOOKS: Introduction to Microprocessorsand Computing £2.75. Interfacing Techni-ques (Sybex) £7 80. Microprocessors (Sybex)£7.80. TTL Bughooks I & II (Sybex) ea.£7.60. Educational Data and Technical Ser-vices, 59 Station Road, Cogenhoe, Nor-thampton NN 7 1 LU.

COLOUR MODULATORKit FO/? ALL TV GRAPHICS!

£9.95 Red tireen Blue ',suds )can be mixed)Available now Nascom Colour Kit.E45.00 int Graphics Software.

WILLIAM STUART SYSTEMSHeronqate Brentwood. Essex

.0277) 810744Bari iu ' Access weLorne

50Hz SUPER BOARDSBRITISH MODEL

boor £190 , vA,Fully built, set Op and tested

AUTHORISED dealer back-upC.T.S., 1 Higher Calderbrook

Littleborough, Lanes.Tel. Littleborough 79332 any time

ADVERTISEMENTINDEX

AJD Direct SuppliesAmbit InternationalAudio ElectronicsBaydisB. BamberBi-PakBK ElectronicsB.N.R.S.Calculator Sales & Service

112107112

6199

4 & 527 & 106

47108

Cambridge Learning Enterprises 40 & 41Catronics 94Chiltmead 102Chromasonics 106Clef Products 114Codespeed 109Comp, Comp, Comp 122 & 123Crimson Elektrik 92Crofton Electronics 94C.S.C. 34Delta Tech & Co 106Doram Electronics 35E.D.A. 27Electrovalue 93Greenbank 70Greenweld 40GR International 93GMT Electronics 84 & 85Hameg Ltd 104Harvelec 93Henry's Radio 27, 36 & 93I LP Electronics 6 & 7Jeremy Lord Synthesisers 66Kramer & Co 108Lascar 35LB Electronics 47L&B Electronics 68Leytronics 114Lotus Sound 28Magnum Audio 61Maplin 100 & 124Marshalls 61Menocrest 17Metac 18, 19, 20 & 21Micro -Circuits 11Minikits 80Monolith 79Mountaindene 97E. R. Nicholls 108NIC Models 66T. Powell 99Powertran Computers 111Powertran Electronics 2 & 8Progressive Radio 94J. W. Rimmer 93Roger Squire's Disco Centre 1 7

Rolls Royce 121Romane Electronics 13R.T.V.C. 55Science of Cambridge 113Scopex 28C. N. Stevenson 42Steve's Electronics 109Strathand 47 & 104Suretron 109Swanley Electronics 99Tandy 75Technomatic 12Teleradio 106Tempus 80 & 81TK Electronics 114Transam 16 & 66Videotime Products 48Watford Electronics 14 & 15Wilmslow Audio 104

120 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

SITUATION VACANT

ILNIMOD

Instrument Mechanicsand Instrument Fitter/Machinists

To work in the following areas of the Instrument Department:-

* Machining and fitting * Assembly * Wiring * Test * Maintenance * Calibration * Enginetest preparation.

The Aero Division of Rolls-Royce Limited are seeking to employ experienced andqualified men and women to join the existing teams based at Derby.

The work involves a wide range of equipment from simple voltage and current meters tocomplex microprocessor and computer based systems.

Applicants should have served a recognised apprenticeship or H.M. Services equivalent inradio/TV, radar, instrumentation, electrics, precision instrument making, fitting, machiningor other relevant field. Whilst experience of instrumentation would be an advantage it is notessential.

The posts are on our dayshift (with 3 shift working as and when required) and on ourpermanent 3 shift system.

The work is interesting and challenging offering scope for promotion.A high basic wage is offered with generous additional premiums for overtime and shift

working. In addition attractive fringe benefits include free safety shoes and overalls,subsidised meals and full factory staff conditions after only 12 months service. In additionthe Company provides a comprehenisve pension scheme with life assurance, excellent sportand welfare facilities. Assistance with relocation expenses will be given in appropriate cases.

To apply either fill in the quick response coupon and mail FREEPOST, (no stamprequired) to: -

M. Barnard, Employment Office, Aero Division, Rolls-Royce Limited, P.O. Box 31,Derby DE2 8XA.

or telephone Derby (0332) 42424 ext 569 for an application form or call in at the:Employment Office, Nightingale Road, Derby, 8.30am until 5pm Monday - Thursday and

8.30am to 4pm Friday, or 9am to 12 noon Saturday.

Quick Response Coupon:R-F/1

Name AgeIAddress

Telephone (if any)IApprenticeship served with (name of company or H.M. Services)

ITick times preferred for informal interviewWeekdays Evenings

Present employer (if you wish to state)

ROLLS.

ROYCE,

Saturday mornings

AERO DIVISIONCome with us into the 21st century

ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980 121

PET COSTS LESSAT COMP and it's

8K - Comes complete witha pedigree integral cassette deck

Full manualssupplied. Powerful 8K Microsoft Basic in ROM.Masses of software available - £499 + VAT16K - Same as above but with newimproved keyboard and cassette suppliedas extra. Machine code monitor on board -

so you can program in 6502 machinecode - £590 + VAT32K - for a little extra get 32K memory 411111010.providing greater storage capacity forprograms or data - £890 + VATExternal Cassette deck for 8K. 16K or 32K - £55 + VATcomplete with cable and connector.

FULL RANGE OF PETSOFTSOFTWARE NOW AVAILABLE

r SORCERER SPEAKSYOUR LANGUAGE

For personal or business use. Thevalue for money around.* 512 by 256 point screen

resolution * 16K or 32KUser RAM * Centronics

Parallel Port * RS232C Serial\Port * Composite IV peak to peak vide

output T.V. output supplied as extra. * 64programmable graphics + 64 standard PET

f'graphics * 79 key keyboard including 16 keynumeric keypad. * Expansion bus for

Word connection to S100 Expansion Box.Processing 16K Sorcerer - £690.00 + VAT

Pac and 32K Sorcerer - f790.00 + VATDevelopment Pac S100 Expansion Box - £210 + VAT

now available,Word Processing Pac - £70 + VAT Development Pac - £70 + VAT

THE TRS80 (Special Scoop)Low Priced, Ready te,

PLUGS INTO YOUR OWN TVUse your own cassette

LEVEL II BASIC WITH 16K USER RAM provides you with possibly the most power-ful micro around. All our TRS8Us are fully converted to English Television Stan-dard and include a U.K. Power Supply, Cassette Leads, Sample Tape, Level I &Level II programming manuals, and special lead that enables you to connectdirect into your own television.Special features of Level Ii Basic enable you to:-- Set or reset any point on the screen - Test for the presence of a point onthe screen (these features enable easy animation) - Save or load data fromcassette under program control - File handling capabilities on cassette usingnamed files. - Graphics blocks as standard - design your own pictures andmany many more features for only £399 + VAT

FULL RANGE OF TRS80SOFTWARE NOW AVAILABLE

THE NEW ITT APPLE (2020)

* Full colour - UHF output * Audio cassette tape interface * Up to 48KRAM on board * BASIC in ROM (graphics commands include COLOUR =

VLIN, HLIN. PLOT and SCRN) * Built in loudspeaker * Buckets of softwareavailable * Disk System (110K byte per drive - includes controller)

only £425 + VAT EX -STOCK

ANADEX DP8000 ONLY £540 + VATPET Connector - £49

The DP 8000 prints the 96 -character ASCIIset in single or double width at 84 linesper minute. The unit operates bi-directionally to print a 9 x 7 matrix onmultiple copy, pin -feed plain paper. This model accepts RS -232C or currentloop serial data at baud rates switchablefrom 110 to 9600 and Parallel Bit data in-put at over 1000 characters per second.

Standard storage capacity of 256 characters Other features include Outof Paper Detector, Top of Form Programming and Skip Over Perforation Control.

video 100 12" BLACK a WHITELOW COST VIDEOMONITOR

Ideal for home, personal and business computer systems 12" diagonal video monitor

Composite video input Compatible with many computer systems Solid-state circuitry for a stable & sharppicture Video bandwidth - 12MHz + 3DB Input impedance - 75 Ohms Resolution - 650 tines Minimum In Central

80% of CRT; 550 Lines Minimum beyondcentral 80%.

Only £79 + VAT

COMP PRO MixerProfessional audio

mixer that you can build yourself and save over £100.

Ws *

. 0 0

111114 AP, 0

4 t'

6 into 2 with full equalization andecho, cve and pan controls.All you need for your ownrecording studio is a stereo tape orcassette recorder.

This superb mixer kit has sliderfaders, level meters andadditional auxilliary inputs.Only £99.90 plus VAT forcomplete kit Plus FREE powersupply valued at £25.00

Ideal forDISCOS STAGE MIXING HOME STUDIOS

AND MANY OTHER APPLICATIONS

MODULATORS UHF Channel 36Standard 6 meg band width £2.25

High Quality 8 meg band width £4.90 EX -STOCK

SHORT C12 CASSETTES FORCOMPUTER PROGRAMMES 10 for £4.00

HIRE PURCHASE AVAILABLE THROUGHHODGE FINANCE.

SEND S.A.E. FOR APPLICATION FORM.

122 ELECTRONICS TODAY INTERNATIONAL - JANUARY 1980

Om.

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313

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AS SEEN INEUROPES FASTEST

JUST

P.E. AUGUST, SEPTEMBEROCTOBER 1979 ompuKIT

SELLINGCHECK

ONETHE

BOARDSPECS.

COMPUTER

UK101

- SAMPLE TAPEWITH EXTENDED

MACHINE CODE MONITORAND DISSASSEMBLER

INCLUDED FREE

The

LOW COSTCompukii UK 101 has

SUPERBOARD IN KIT FORMeverything a one board 'superboard' should have

Uses ultra powertul 6502 microprocessor tl,. 50H; Frame refresh or steady clear picture1

417,U S A products with 6061s frame refresh alwaysresults in jittery dIsplaysl .I l I 1 i'

Simpleconsise

Soldering due to clear andinstructions compiled by

Dr. A.A. Berk, BSc.PhD48 chars by 16 -- 1K memory mapped videosystem providing high speed access to screen displayenabimg animated games and graphs 11 till '11 : Ill,. - -Extensive 256 character set which includes full

1c.:i $ 1. . BAupper and lower case alphanumerics Greek symbolsfor mathematical constants and numerous graphic

NO EXTRAS NEEDED JUST HIT'RETURN' AND GO.

chaireanywhereformshapeon the screen

Video output and UHF Highgrade modulator (8MzBandwidth, which connects direct to the aerial socket

..

' '. II Pt -of your T V Channel 36 UHFFully stabilised 5V power supply including trans

former on board 1111*;

II.

Build, understand, and program yourown computer for only a small

outlay.Standard KANSAS city tape interface 'providing

high reliability program storage --use on anystandard domestic tape or cassette recorder

4K user RAM expandable to 8K on board £49A

. :

,

s

cextra

T l., Ia 40 line expansion interface socket on board forattachment of extender card containing 24K RAM anddisk controller (Ohio Scientific :ompatiblel

6502 machine through

includingKIT ONLY £219 + VAT

RF Modulator & Powersupply.

Absolutely no extras.a code accessible powerful2K machine code monitor on board

High quality thru plated PCB with all IC'smounted on sockets

.Professional 52 Key keyboard in 3 colours - soft- and from Pet. Apple and Sorcerer easy.ware polled meaning that all iebouncing and key

'8K Microsoft Basic means conversion to

Many compatible programs already in print.decoding done In software SPECIAL CHARACTERS

Available ready assembled andtested, ready to go for

£269 + VATCOMMANDS 0. Erases line being typed, then providesCONT LISTSTATEMENTS

NEW NULL RUN carriage return, line feed.Erases last character typed. FUNCTIONS

CR Carriage Return - must be at the end of ABS, x,CLEAR DATA DEF DIM END FOR each line LOGIX)GOTO GOSUB IF GOTO IF THEN INPUT LETNEXT ON GOTO ON GOSUB POKE PRINT READ Separates statements on a line.

CONTROL/C Execution or printing of a listSPCM

REM RESTORE RETURN STOP FREi Xiis interrupted at the end of a line.EXPRESSIONS "BREAK IN LINE XXXX" is printed, in SGNiXI

OPERATORS dicating line number of next statement to be USROI32 +32 executed or printed.

STRINGt NOT AND OR > < <, > n- <, RANGE 10 to 10

CONTROL/0 No outputs occur until return ASCixSiVARIABLES to command mode. If an Input stateRIGHTS(XSABC 7 and loo, letter variables merit is encountered. either anotherThe ,Moyo ,,an an be subscripted when used in an CONTROL/0 is typed, or an error occurs. LENiXS,,,,, Str,5 vri,lan,O, uSl' abmo, ritir-no,, pill, Si' q A$ ", Equivalent to PRINT VAL,X$1

ATNIXI COSIXI EXP(X)PEEKili POSIII RNDiX

INTiSX7IX'TABM TAN,X)

SINIXI

FUNCTIONSCHRSSiii FREIX$i LEFTSixS I,

MIDSt XS I JI

STRSIX1bment

COLOUREnables you to choose you foreground

ADD-ONthe background

documentation

CARDcolour anywhere

and parts

AVAILABLEon the screen.in kit form.

Flash anySOON

character on the screen at will. Full

-11,

,

1,

1l'. 4THEAtari'svariationsHaveYou

ATARIVideo

andfun while

can play rousing,

Computeroptionsyou sharpen

VIDEO COMPUTERSystem now offers more than

in twenty great Game ProgramTmyour mental and physical

challenging. sophisticated video

1300cartridges!

coordination.games,

different

the

SYSTEMgame

coA5e.\11):Cgames that made Atari famous.

You'll have thrill, in the thick dogfight,il ill Y v ii thrill after whether you're of a screeching around a racetrack,or dodging asteroids in an alien galaxy. With crisp bright color (on color TV) and incredible. true -to -4 . life sound effects. With special circuits to protect your TV.A'

-:,,

,..

od A

Cartridges now available in stock:Basic Maths - Hunt & Score' - Space War -Video Olympics - Outlaw - Surround - Sky Diver 0.3.9°.4

acs

5511057I-6 Basket Ball - Air Sea Battle - Black Jack - Breakout eacXi.,Ar4 iseaaN\ssk2,2,:st:e6Codebreaker - Miniature Golf.

NI'1.,,,,,Extra Paddle Controllers - £14.90 + VAT'Keyboard Controllers - £16.90 VAT

1:-173- 1",_5NNI ° -

-AP- ..

SPECIAL OFFER WHILE STOCKS LAST:Free extra cartridge of your choice please state 1st 2nd and 3rd preference.

LPlease add VAT to all prices - Delivery at cost, will be advised at time of purchase. Please makecheques and postal orders payable to COMPSHOP LTD.. or phone your order quotingBARCLAYCARD. ACCESS. DINERS CARD or AMERICAN EXPRESS number.

CO)N.= .1CREDIT FACILITIES ARRANGED - send S.A.E. for application form.- I

J14 Station Road, New Barnet, Hertfordshire, EN5 IOW Telex: 298755 TELCOM GTelephone: 01-441 2922 (Sales) 01-449 6596__I

OPEN 10 am 7 pm - Monday to SaturdayCOMP

COMPUTER 11.611TUM- *NOW OPEN ALL DAY For Shop Sales COMPONENTSSUNDAY - Only*

NSAClose to New Barnet BR Station - Moorgate Line. Part of the Compshop Ltd. Group)

A 63 -key ASCII keyboard with 625 -lineTV interface, 4 -page memory andmicroprocessor interface. Details inour catalogue.

Our catalogue even includes somepopular car accessories at marvellousprices.

A 10 -channel stereo graphic equaliserwith a quality specification at anunbeatable price when you build ityourself. Full specification in our

BreadboardI919

'Asev

bg,g,ercatalogue.

arrd,better

Oar\\atlearYs

the orerote

sbotAdOss.

These are just some of the metal caseswe stock. There are dozens of plasticones to choose from as well.See pages 52 to 57 of our catalogue.

A massive newcatalogue fromMaplin that's evenbigger and betterthan before. If youever buy electroniccomponents, this isthe one catalogueyou must not bewithout. Over 280pages - some in fullcolour - it's acomprehensiveguide to electroniccomponents withhundreds ofphotographs andillustrations andpage after page ofinvaluable data.

Our bimonthly newsletter contains guaranteed prices.special offers and all the latest news from Maplin.

Jib IR

::: Rises'Mobile amateur radio, TV and FMaerials plus lots of accessories aredescribed in our catalogue.

A digitally controlled stereosynthesiser the 5600S with morefacilities than almost anything up to£3,000. Build it yourself for lesspthan E750. Full specificatiVin our catalogue.

A superb range of microphones andaccessories at really low prices.Take a look in our catalogue-send thecoupon now!

An attractive mains alarm clock withradio switching function and batteryback up! Complete kit with case onlyE18.38 (incl. VAT & p & p) MA1023module only £8.42 (incl. VAT).

ELECTRONIC SUPPLIES LTD

JPost this

eri coupon now for your 11

copy of our 1979-80 f /catalogue price 70p.

Please send me a copy of your 280 pagecatalogue. I enclose 70p (plus 37p p&p).

If I am not completely satisfied I may return the

n catalogue to you and have my money refundedIf you live outside the U.K. send £1.35 or ten

International Reply Coupons.

I enclose £1.07.

ev.INAME

ADDRESS

l)

oo

Fil 1 BE'

A'hi-fi stereo tuner with medium andlong wave, FM stereo and UHF TV

sound! Full construction details in ourcatalogue.

A superb technical bookshop in yourhome! All you need is our catalogue.Post the coupon now!

Add-on bass pedal unit for organs.Has excellent bass guitar stop forguitarists accompaniment.Specification in our catalogue.

All mail to: -PO. Box 3, Rayleigh, Essex SS6 8LR.

Telephone: Southend (0702) 554155.Shop: 284 London Road, WeStcliff-on-Sea, Essex.(Closed on Monday).Telephone: Southend (0702) 554000.