Practice 1: Use of the ohmmeter, Voltmeter and Ammeter in measurements of D.C

Practice 1: Use of the ohmmeter,

Voltmeter and Ammeter in measurements

of D.C.

1CM15

INSTITUTO POLITÉCNICO NACIONAL | ESCOM

Integrants:

Miramontes Romero Alejandro

Ortiz Ubaldo Ezequiel

Felipe Figueroa del Prado

Practice 1.

Fundamental análisis of circuits

Practice 1: use of ohmmeter, ammeter and voltmeter

1

Index page

Objective………………………………………………………………………………………………………………………………………2

Equipment and materials……………………………………………………………………………………………………………..2

Theoretical introduction……………………………………………………………………………………………………………….2

Development of the practice………………………………………………………………………………………………………..3

Use of the Ohmmeter…………………………………………………………………………………………………………………..3

Use of voltmeter…………………………………………………………………………………………………………………………..4

Use of ammeter……………………………………………………………………………………………………………………………5

Simulations…………………………………………………………………………………………………………………………………..6

Calculus……………………………………………………………………………………………………………………………………….17

Questionnaire……………………………………………………………………………………………………………………………..19

Conclusion…………………………………………………………………………………………………………………………………..19

Image…………………………………………………………………………………………………………………………………………..20


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Objective

The students will understand the proper handling of measurement instruments, so that at

the end of the practice, he must be able to:

Proper use of the digital ohmmeter

Proper use of the digital voltmeter.

Proper use of the digital ammeter.

EQUIPMENT MATERIAL

1 DIGITAL MULTIMETER 1 protoboard 1 SOURCE OF VARIABLE VOLTAGE 1 resistor of 1kΩ 4 TIPS BANANA-CAYMAN 1 resistor of 560Ω

2TIPS CAIMÁN-CAYMAN 1 resistor of 680Ω

1 resistor of 330Ω

Wire connection

Theoretical Introduction

The current or voltage can be measured by means of ammeters or voltmeters, figure 1

shows 2 common forms of meters; one of the analog meter has a needle that moves on a

calibrated scale whose angular deflection depends on the magnitude of the variable that

measures. While the other is a digital meter which shows a series of digits in the screen,

indicating the magnitude of the variable that measures. Figure 2 shows the symbols of the

voltmeters and ammeters that are used in the electrical circuit diagrams.

Figure 1. a) Analog meter b) Digital meter Figure 2. Symbol of each meter


3

To measure the current in the branch of a circuit, you must open this branch and the

ammeter should be inserted so that it is connected in series with the element from which

you want to know their current. It is said that two elements are in "series" if one end of one

joins with one end of the other, and there is no conductor connected to that union. The

current flowing through that path, necessarily pass through the current meter (ammeter).

To measure the voltage between two points, the voltmeter connects in parallel with the

electronic device from which you want to know the voltage drop. Two elements of two

terminals are connected in parallel if the terminals are connected one to the other

terminals. It doesn't matter if in these unions or not there is another connection. The

essential characteristic of a parallel connection, which, through the elements there is the

same voltage.

Development of the practice

Use of the ohmmeter.

Without energize any circuit element, measure the resistance value that presents each

resistor, as shown in figure 3 and fill in the table 1.

Figure 3. Connection of the Ohmmeter.

Ohmmeter


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Table1. Measure of

resistive values.

Use of Voltmeter

Figure 4 shows how it should be to measure the voltage on an element. With the voltage

source off, install the circuit in figure 5. Once armed the circuit switch on the voltage source

and fill in the table 2.

Figure 4. Example of connection of voltmeter

Figure 5. Serial circuit

Resistance Measure with digital ohmmeter Value in the color codice

R1 327.3 Ω 330 Ω

R2 .986 k Ω 1k Ω

R3 560 Ω 560 Ω

R4 655 Ω 680 Ω

charge

voltmeter

schematic

Connection of the circuit in the protoboard


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TABLE 2. MEASURE OF VOLTAGE

Use of ammeter

Figure 6 shows how you have to connect the ammeter for current measure in element.

Figure 6. Connection of the ammeter example.

Source of

voltage DIGITAL MULTIMETER MEASURED VALUES

R1 y R2

voltage

R1 voltage R2 voltage R1 y R2

voltage R1 voltage R2 voltage

E=1V 1.004 V 0.754 V 0.249 V 1 V .75 V .248 V

E=2V 2.075 V 1.559 V 0.516 V 2 V 1.5 V .496 V

E=3V 3.022 V 2.271 V 0.751 V 3V 2.25 V .744 V

E=4V 4.008 V 3.01 V 0.997 V 4 V 3.007 V .992 V

E=5V 5.20 V 3.90 V 1.29 V 5 V 3.759 V 1.24 V

E=6V 6.24 V 4.69 V 1.55 V 6 V 4.511 V 1.488 V

E=7V 7.27 V 5.46 V 1.80 V 7 V 5.263 V 1.736 V

E=8V 8.33 V 6.25 V 2.07 V 8 V 6.015 V 1.984 V

E=9V 9.31 V 6.99 V 2.32 V 9 V 6.766 V 2.233 V

E=10V 10.40 V 7.81 V 2.59 V 10 V 7.51 V 2.481 V

E=11V 11.48 V 8.60 V 2.86 V 11 V 8.27 V 2.729 V

q 12.5 V 9.38 V 3.11 V 12 V 9.022 V 2.977 V

ammeter

charge

ee

schematic Connection of the circuit in the protoboard


6

With the voltage source off, install the circuit in figure 7. Once armed the circuit

switch on the voltage source and fill in the table 3.

Table 3.measure of current.

Simulations.

Use of voltmeter

Table 2.

Source of voltage with 1 V.

Source of

voltage Digital multimeter

Current

beetwen R1

y R2

Current in

R1 Current in

R2

E=1V 3.47 mA 1.49 mA 1.76 mA

E=2V 6.56 mA 3.06 mA 3.6 mA

E=3V 9.9 mA 4.5 mA 5.36 mA

E=4V 13 mA 6 mA 7.16 mA

E=5V 16.3 mA 7.46 mA 8.9 mA

E=6V 19.56 mA 8.93 mA 10.76 mA

E=7V 22.65 mA 10.45 mA 12.51 mA

E=8V 26.05 mA 11.85 mA 14.3 mA

E=9V 29.29 mA 13.36 mA 16.11 mA

E=10V 32.5 mA 14.87 mA 17.87 mA

E=11V 35.93 mA 16.39 mA 19.71 mA

E=12V 39.28 mA 17.9 mA 21.61 mA


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Source of voltage with 3 V


8




9


Source of voltage with 7V


10




11




12



13

Use of Ammeter

Table 3.





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Calculus

Use of voltmeter

To calculate values of table 2. Voltage measure, we have to use the Ohm’s law.

Calculus with a source of voltage of 1V.

𝐼 =𝑉

𝑅=

1𝑣

1𝑘Ω + 330Ω= 7.518𝑋10−4

𝑉1 = 𝐼 ∗ 𝑅1 = (7.518𝑋10−4 ) (1𝐾) = .75 𝑉

𝑉2 = 𝐼 ∗ 𝑅2 = (7.518𝑋10−4 ) (330) = .248𝑉

Calculus with a source of voltage of 2 V

𝐼 =𝑉

𝑅=

2𝑣

1𝑘Ω + 330Ω= 1.5037𝑋10−3

𝑉1 = 𝐼 ∗ 𝑅1 = (1.5037𝑋10−3)(1𝐾) = 1.5𝑉

𝑉2 = 𝐼 ∗ 𝑅2 = (1.5037𝑋10−3)(330) = .496𝑉

Calculus with a source of voltage of 3V

𝐼 =𝑉

𝑅=

3𝑣

1𝑘Ω + 330Ω= 2.2556𝑋10−3

𝑉1 = 𝐼 ∗ 𝑅1 = (2.2556𝑋10−3)(1000) = 2.25𝑉

𝑉2 = 𝐼 ∗ 𝑅2 = (2.2556𝑋10−3)(330) = .744𝑉


𝐼 =𝑉

𝑅=

4𝑣

1𝑘Ω + 330Ω= 3.0075𝑋10−3

𝑉1 = 𝐼 ∗ 𝑅1 = (3.0075𝑋10−3)(1000) = 3.007𝑉

𝑉2 = 𝐼 ∗ 𝑅2 = (3.0075𝑋10−3)(330) = .992𝑉


𝐼 =𝑉

𝑅=

5𝑣

1𝑘Ω + 330Ω= 3.7593𝑋10−3

𝑉1 = 𝐼 ∗ 𝑅1 = (3.7593𝑋10−3)(1000) = 3.759𝑉 𝑉2 = 𝐼 ∗ 𝑅2 = (3.7593𝑋10−3)(330) = 1.24𝑉


𝐼 =𝑉

𝑅=

6𝑣

1𝑘Ω + 330Ω= 4.5112𝑋10−3


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𝑉1 = 𝐼 ∗ 𝑅1 = (4.5112𝑋10−3)(1000) = 4.511𝑉 𝑉2 = 𝐼 ∗ 𝑅2 = (4.5112𝑋10−3)(330) = 1.488𝑉


𝐼 =𝑉

𝑅=

7𝑣

1𝑘Ω + 330Ω= 5.2631𝑋10−3

𝑉1 = 𝐼 ∗ 𝑅1 = (5.2631𝑋10−3)(1000) = 5.263𝑉 𝑉2 = 𝐼 ∗ 𝑅2 = (5.2631𝑋10−3)(330) = 1.736𝑉


𝐼 =𝑉

𝑅=

8𝑣

1𝑘Ω + 330Ω= 6.0150𝑋10−3

𝑉1 = 𝐼 ∗ 𝑅1 = (6.0150𝑋10−3)(1000) = 6.015𝑉 𝑉2 = 𝐼 ∗ 𝑅2 = (6.0150𝑋10−3)(330) = 1.984𝑉


𝐼 =𝑉

𝑅=

9𝑣

1𝑘Ω + 330Ω= 6.7669𝑋10−3

𝑉1 = 𝐼 ∗ 𝑅1 = (6.7669𝑋10−3)(1000) = 6.766𝑉 𝑉2 = 𝐼 ∗ 𝑅2 = (6.7669𝑋10−3)(330) = 2.233𝑉


𝐼 =𝑉

𝑅=

10𝑣

1𝑘Ω + 330Ω= 7.518𝑋10−3

𝑉1 = 𝐼 ∗ 𝑅1 = (7.518𝑋10−3)(1000) = 7.51𝑉 𝑉2 = 𝐼 ∗ 𝑅2 = (7.518𝑋10−3)(330) = 2.481𝑉


𝐼 =𝑉

𝑅=

11𝑣

1𝑘Ω + 330Ω= 8.2706𝑋10−3

𝑉1 = 𝐼 ∗ 𝑅1 = (8.2706𝑋10−3)(1000) = 8.27𝑉 𝑉2 = 𝐼 ∗ 𝑅2 = (8.2706𝑋10−3)(330) = 2.729𝑉


𝐼 =𝑉

𝑅=

12𝑣

1𝑘Ω + 330Ω= 9.0225𝑋10−3

𝑉1 = 𝐼 ∗ 𝑅1 = (9.0225𝑋10−3)(1000) = 9.022𝑉 𝑉2 = 𝐼 ∗ 𝑅2 = (9.0225𝑋10−3)(330) = 2.977𝑉


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Questionnaire

1. What is the characteristic of a series circuit?

Current is the same in all the elements and the voltage is distributed

2. What is the characteristic of a parallel circuit?

Current is delivered in each element and voltage is the same

3. What is the main difference between an analog meter and a digital?

Digital is more accurate than an analog

4. Why an ammeter must not be connected in parallel?

Because it burns

5. Why should no-energize the circuit when measuring the resistance of

an electrical circuit?

The value of the resistance may vary

Conclusions

In the practice we connect resistors in series and parallel. Also learn the operation of the

multimeter to measure resistance, voltage and current in our circuit. We used the Ohm’s

law to calculate the values of voltages in the second table.


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Practice 1: Use of the ohmmeter, Voltmeter and Ammeter in measurements of D.C

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Transcript of Practice 1: Use of the ohmmeter, Voltmeter and Ammeter in measurements of D.C