Pengukuran Besaran ListrikRE 1323 Potensiometer

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Potensiometer

Instrumen yg mengukur tegangan yg tidak diketahui dg cara membandingkannya thd tegangan yg diketahui. Teg yg diketahui dpt disuplai dari sebuah sel standar atau sumber teg referensi yg diketahui. Pengukuran2 dg perbandingan menghasilkan akurasi yg lbh tinggi

krn hsl yg diperoleh tdk tergantung defleksi jarum penunjuk; tp tergantung pd ketelitian teg standar yg diketahui tsb.2

Potensiometer

Potensiometer memanfaatkan kondisi setimbang atau kondisi nol.

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Rangkaian dasar potensiometer: Potensiometer kawat geser (slide-wire)

Tahanan total kawat geser: 200 ohm. Awal: Kalibrasi / arus kerja distandarkan Sel Standard**(Weston Cell)1.019 V Posisi kontak geser 101.9 cm (berarti 101.9 ohm) Tahanan geser diatur shg bila saklar ditutup, galvanometer tdk defleksi. ->Arus kerja 10 mA

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Rangkaian dasar potensiometer: Potensiometer kawat geser (slide-wire)

Setelah dikalibrasi, setiap teg DC kecil yg tdk diketahui dpt diukur. Kontak geser digerakkan sampai galvanometer tdk menunjukkan defleksi.Shg teg sepanjang kawat geser sebanding dg posisi kontak geser (mis. 143 cm = 1.43 V)

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Figure 23: Precision thermocouple slide-wire potentiometer Made by Leeds & Northrup, 1913.

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*Potensiometer Pengganti Tahanan geser

Tahanan Piring : 1 Switch 0.1 Volt Kawat geser 200 skala 1 skala = 0.0005 Volt7

*Potensiometer 2 Rangkuman

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*Penyederhanaan Potensiometer 2 Rangkuman

Sekali instrumen dikalibrasi pada range x1, kalibrasi range x10 tdk diperlukan. ->shg teg E hrs tetap sama pd kedua posisi range -> arus total batere hrs sama utk kedua posisi range. R(x1) = R(x0.1)9

*Rangkaian (a) Saklar x1 (b) saklar x0.1

R(x1) = R(x0.1)

Rm ( R2+ R2) R2( R2+ Rm ) = Rm + R2 + R2 R2 + R2 + Rm R2Rm = R2R2 R2 = Rm

Selanjutnya R2 ditentukan dg perhitungan10

*Potensiometer 3 Rangkuman

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At the heart of the potentiometer is a long slide wire. In the Type K potentiometer this was in the form of a tenturn coil, a design due to Kohlrausch. The potentiometer was used with an external standard cell and an external galvanometer.

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POTENSIOMETER SEBAGAI KOTAK VOLT Potensiometer yang digunakan untuk pengukuran tegangan biasanya hanya pada 0 1.6 Volt. Jika tegangan yang diukur lebih besar digunakan rangkaian pembagi tegangan/kotak Volt

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From the 1940 Central Scientific Company catalogue: Volt Box, L&N, for use with Students Potentiometer and Type K Potentiometer. The volt box has three ranges which permit measurement and calibration up to 15, 150 and 300 volts, respectively. Accuracy 0.04%.

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The volt box on the left was made by James W. Queen of Philadelphia. It looks as if it has undergone some internal modifications. The paper labels notes that it will divide the input voltage by 200, 100 or 10.

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POTENSIOMETER SEBAGAI KOTAK SHUNT Kotak shunt dimaksudkan utk digunakan bersama potensiometer dalam pengukuran presisi arus searah dan untuk kalibrasi Amperemeter DC dan Wattmeter

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Figure 15: Multirange Shunt Box Made by Leeds & Northrup Co., Philadelphia The multirange shunt allows the determination of currents from 0 A to 7.5 A,

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*Potensiometer untuk kalibrasi voltmeter dan ampermeter

Metoda potensiometer umum digunakan untuk kalibrasi voltmeter, ampermeter, dan wattmeter.

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*Potensiometer Untuk Kalibrasi Voltmeter

Pembacan Skala Voltmeter DC 0.0 1.0 2.0 3.0 5.0

Pembacaan Potensiometer 0.00 0.95 2.00 3.05 4.1

Koreksi

Pembacan Skala Voltmeter DC 6.0 7.0 8.0 9.0 10.0

Pembacaan Potensiometer 6.15 7.10 8.15 9.20 10.25

Koreksi

0.0 -0.05 +0.05 +0.1 +0.1

+0.15 +0.1 +0.15 +0.20 +0.25

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*Potensiometer untuk kalibrasi voltmeter dan ampermeter

Bila sebuah voltmeter menerima kalibrasi awalnya, voltmeter tsb akan dilengkapi suatu skala baru:

Teg yg tertera pd voltmeter diatur sampai potensiometer menunjukkan nilai yg diinginkan, lalu skala yg baru dituliskan.

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*Potensiometer Untuk Kalibrasi Amperemeter

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*Self Balancing Potensiometer

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Potentiometer as electronic component

A potentiometer is a potential divider, a three terminal resistor where the position of the sliding connection is user adjustable via a knob or slider.

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Leeds and Northrup made a series of lesser potentiometers designed for introductory work by students. This student potentiometer has a single-turn slide wire instead of the ten-turn slide wire used in the TypeK series. This particular instrument is in the Greenslade Collection.

http://physics.kenyon.edu/EarlyApparatus/Electrical_Measurements/Potentio meter/Potentiometer.html

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http://gsc.nrcan.gc.ca/geomag/lab/virtual

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http://www.allaboutcircuits.com/vol_1/chp http://physics.kenyon.edu/EarlyApparatus http://chem.ch.huji.ac.il/instruments/test/

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