VOLTAGE AND CURRENT DIVISION LAB REPORT.pdf

VOLTAGE AND CURRENT DIVISION Mhlanga S 23721804 and Dlamini L.S 23772727 Experiment Done 13/ 03/ 2013

ABSTRACT

 An experiment experiment to verify the the properties of voltage and and current division division is presented. presented. The voltage voltage divider  divider  is created using two resistors connected in series in a circuit. The current divider is created using 2 resistors connected in parallel. It is found that if one of the resistors in the voltage divider is greater  than the other, more voltage will be dropped across it. It is also found that the greater the resistor is, less current will pass through. Experimental, simulated and calculated results are found to be in good agreement.

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TABLE OF CONTENTS

1.

INTRODUCTION……………………………………………… INTRODUCTION……………………… …………………………………………………… ……………………………………………………… …………………………2 2

2.

THEORY…………………………………………………… THEORY………………………… ……………………………………………………… ……………………………………………………..…3, ………………………..…3, 4

3.

PROCEDURE…………………………..……………………………… PROCEDURE………………………… ..…………………………………………………………… ………………………………………………5 …………………5

4.

RESULTS AND DISCUSSION………………………… ON…………………………………………………… …………………………………………………… ………………………………..6, ……..6,

5.

CONCLUSION…………………………………………………… CONCLUSION……………………… ……………………………………………………… …………………………………………………… ………………………….8 .8

6.

REFERENCES…………………………………………… REFERENCES………………… …………………………………………………… ……………………………………………………… ………………………………….9 …….9

1.

INTRODUCTION

The aim of the lab is to investigate the concepts of voltage and current division. Voltage and current division is an application of Kirchhoff’s Laws. A voltage divider and a current divider will be designed. In electronics or EET, a voltage divider (also known as a potential divider) is a linear circuit that produces an output voltage (V out) that is a fraction f raction of its input voltage (V in). Voltage division refers to the partitioning of a voltage among the components components of the divider. a current divider is a simple linear circuit that produces an output output current (IX) that is a fraction f raction of its input current (IT). Current division refers to the splitting of current between the branches branches of the divider. The currents in the various branches of such a circuit will always divide in such a way as to minimize the total energy expended [1]. In this experiment the voltage and current division properties will be verified. Slight deviations are caused by experimental errors which include taking somewhat wrong readings due to fluctuating values in the ammeter and voltmeter.

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2.

THEORY

Voltage and current division allow us to simplify the task of analysing analysing a circuit. Voltage Division allows allows us to calculate what fraction of the total voltage across a series string of resistors is dropped across any one resistor . . For the circuit of Fig.1 voltage division formulas are:

V1 

 R1 V S  ( R1 R2)

(1)

V2

 R2 V S  ( R1 R2)

(2)



Where V is the voltage and R is the resistance

Figure.1 Voltage divider divider circuit [2]. Used to measure what fraction of the total voltage is dropped across any one resistor.

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Current Division allows allows us to calculate what fraction of the total current into a parallel string of resistors flows through any one of the resistors. For the circuit of Fig.2 current division formulas are:

I1 

I2



 R2  I S  ( R1 R2)  R1

( R1 R2)

 I S 

(3)

(4)

Where I is the current and R is the resistance

Figure.2 Current Divider circuit [2] Current divider circuit used to calculate what fraction of the total current into a parallel string of  resistors flows through any one of the resistors.

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3.

PROCEDURE

3.1 Voltage Division The circuit was constructed as shown in Figure 3. The voltages v1 and v2 were measured by choosing a nd setting the variable power supply voltage Vs = 5V. R1 = 5.6 KΩ, R2 = 1.5 KΩ and This step was repeated for R1 = R2 = 5.6 KΩ and the measurements measure ments were noted down. The voltages V1 and V2 were calculated by using the formulas (1) and (2) in each case.

Figure.3 Voltage divider circuit [2]

3.2 Current division  A circuit was constructed as as shown in figure 2. The currents currents Is, I1 and I2 were measured measured by choosing choosing R1 = 2.2 KΩ, R2 = 5.6 KΩ and a nd Rs=1 KΩ .The variable power supply voltage was set at Vs=10 V. This step s tep was repeated by using R1=R2 =2.2 KΩ and the measurements were noted down.

Figure.4 Current divider circuit [2]

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4. RESULTS AND DISCUSSION

4.1 Voltage Division Results Tables 4.1, 4.2 and 4.3 show the calculated, simulated and experimental results.

Table 4.1 Calculated results R(KΩ) V1(v) R1=5.6, R2=1.5 3.94 R1=5.6, R1=5.6 2.50

V2(v) 1.06 2.50

Table 4.2 Simulated results R(KΩ) V2(v) R1=5.6, R2=1.5 3.94 R1=5.6, R1=5.6 2.50

V2(v) 1.06 2.50

Table 4.3 Experimental results R(KΩ) V1(v) R1=5.6, R2=1.5 3.98 R1=5.6, R2=5.6 2.51

V2(v) 1.06 2.53

The voltage results convincingly seem to be in good agreement. The tables clearly indicate that the calculated and simulated results were found to be the same. Slight deviations in the experimental results might have been caused by fluctuating values in the ammeter making it hard to read precise values. In addition, setting the voltmeter to exactly 10V on the Digital Lab also proved to be a difficult task because the knob was too sensitive. If this experiment is to be redone, improvements can be made by taking enough time to set the source voltage on the Digital Lab to the correct value.

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4.2 Current Division Results Tables 4.4, 4.5 and 4.6 show the calculated, simulated and experimental results. Table 4.4 Calculated Results R(Ω) R(Ω) Is(mA) R1=1, R2=2.2, R3=5.6 3.88 R1=1, R2=2.2, R3=2.2 4.76

I1(mA) 2.79 2.38

I2(mA) 1.09 2.38

Table 4.5 Simulated results R(Ω) R(Ω) R1=1 , R2=2.2 , R3=5.6 R1=1, R2=2.2, R3=2.2

Is(mA) 3.88 4.76

I1(mA) 2.79 2.38

I2(mA) 1.09 2.38

Table 4.6 experimental results R(Ω) R(Ω) Is(mA) R1=1, R2=2.2, R3=5.6 3.89 R1=1, R2=2.2, R3=2.2 4.81

I1(mA) 2.79 2.42

I2(mA) 1.10 2.39

The calculated, simulated and experimental current results are also in convincing compliance. The calculated and simulated results gave out corresponding values. On the other hand the experimental results proved to be somewhat different from the calculated and simulated results. This might have been caused by the fact that the ammeter that was used to measure the current would slightly alter the values making it very possible to take wrong readings. If the experiment is to be redone, improvements can be made by allowing the ammeter to settle to one value before taking readings to avoid taking wrong reasons.

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5.

CONCLUSION

 An experiment experiment to verify the the properties of voltage and and current division division was presented. presented. The voltage voltage divider was created using two resistors connected in series in a circuit. The current divider was created using 2 resistors connected in parallel. It was found that if one of the resistors in the voltage divider  was greater than the other, more voltage was dropped across it. It was also found that the greater the resistor was, less current passed through. Experimental, Experimental, simulated and calculated results were found to be in good agreement. Slight deviations were caused by experimental errors which included taking somewhat wrong readings due to fluctuating values in the ammeter and voltmeter.

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6.

REFERENCES

[1] http://en.wi http://en.wikipedia.org/wi kipedia.org/wiki/Voltage_d ki/Voltage_divider  ivider  [2] Circuit drawings taken from Electronics Laboratory Manual http://www.wisc-online.com/Objects/ViewObject.aspx?ID=DCE3502

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