Electric Circuits Lab Manual

Dhofar University

School of Engineering

Electrical and Computer Engineering Department

Electric Circuits Lab

Lab Manual

Prepared By,

Sheik Mohammed Sulthan

Salalah, Sultanate of Oman

2 EECE210L Electric Circuits Laboratory

CONTENTS

1. Study of OrCAD Pspice Simulation 2. Using Oscilloscope and Function Generator 3. Using Multi meter 4. Current Divider Design and verification of Kirchhoff’s Law 5. Voltage Divider Design and verification of Kirchhoff’s Law 6. Mesh Analysis 7. Verification of Thevenin’s theorem 8. Source transformation Technique 9. Verification of Superposition theorem 10.Transient Analysis of RL Circuits 11.Transient Analysis of RC Circuits 12.Measurement of Power in AC Circuits 13.Measurement of Powerfactor in R, RL and RC Circuits 14.Verification of Kirchhoff’s Law in Frequency Domain


Experiment No.01

Study of OrCAD Pspice Simulation

Objective: To study the operation and functions of OrCAD Pspice by design and

simulate the simple electric circuits.

Q1. Calculate the current, voltage across the element and the power delivered by the source theoretically and simulates the circuit, obtain the output using OrCAD Pspice for the circuit shown in Figure 1.

Schematic diagram:

4 Ohm

24V DC

Figure 1

Procedure

1. Use Ohm's Law (I=E/R) to calculate current flowing through the circuit. 2. Calculate the value of voltage across the element and the power delivered by the

source. 3. Create a new project in OrCAD Pspice and connect the elements as shown in

Figure 1. 4. Change the value of elements and save the project. 5. Create a new simulation profile by entering Pspice and edit the simulation profile. 6. Apply the simulation profile and run simulation. 7. Add plot to window using Plot if necessary and click on trace to add the

parameter you need to view the output. 8. Obtain the output file by entering simulation and click on view output file

document. 9. Copy and Save the output files by copy to clip board from Window bar on the tool

bar. 10. Compare the simulation output with the calculated values and verify the result.


Calculations:

(a) Define Ohm’s Law (b) Given Data (c) Formulae Used (d) Calculation (e) Answers

Result:

Thus the OrCAD Pspice has been studied by design and simulated simple electric circuit.

Lab Sheet Format:

1. Title 2. Objective 3. Equip. and Comp. 4. Schematic Diagram 5. Procedure 6. Circuit Diagram ( with values) 7. Calculation 8. Simulation Circuit 9. Output

a. Plot (Voltage, Current, Power) b. Output File

10. Result

Q2. Calculate the voltage across the element and the power delivered by the source theoretically and simulate the circuit; obtain the output using OrCAD Pspice for the circuit shown in Figure 2.

10 A dc

3 Ohms


Experiment No.02

Using Oscilloscope and Function generator for Measurement and

Testing purposes

Objective: To familiarize with the use Oscilloscope and Function generator for Measurement

and Testing purposes and interface the oscilloscope with PC to obtain the results

Equipments and Components

Oscilloscope Function generator Connecting probes

Theory:

The important points about an oscilloscope:

An oscilloscope is a voltage measurement device. Unlike a voltmeter, an oscilloscope does not display a single number. An oscilloscope displays signals - voltages that are functions of time. Oscilloscopes can measure signal parameters - like frequency, peak-to-peak

voltages, RMS values of signals, etc.

Since an oscilloscope displays time-varying signal, you need a voltage source that produces a time-varying signal. Some sources of time-varying voltages include the following - which is very far from an exhaustive list.

A function generator (also often referred to as a signal generator) produces standard kinds of signals for test purposes. Those signals include sinusoidal signals, triangles, square wave signals and even random signals.

Measuring a Signal

Set the frequency of the signal generator output to 2 kHz. Set the amplitude of the signal generator output to 2 volts. Connect the output of the signal generator to the oscilloscope. Be sure that the

two grounds are connected together. If you use a coax cable make sure you have it connected correctly.

Now you need to set the oscilloscope so that it can display the signal. If you're lucky the oscillscope will have an autoscale button. If not:


Be sure that the timebase is set to something like 0.5 milliseconds/cm. A 1kHz signal has a period of one millisecond. This setting will let you see a few cycles of a 1 kHz signal.

Be sure that the vertical sensitivity is set to something like 0.5 volts/cm. Adjust the trigger: The oscilloscope needs a signal to tell it when to start the

display process - moving the dot across the screen.

Triggering the oscilloscope

The trigger can be an external signal, the power line, or the signal you are displaying. Usually, the dot starts across the screen when the trigger signal goes through zero volts - but you can change the voltage level if you want. If you are using the power line, then you are triggering with a signal that usually has no relation to the signal being displayed. When that happens it is very frustrating trying to figure out why you see chaos.

In multi-channel scopes, you can trigger off Channel 2, when you're only putting a signal into Channel 1. If there is no signal going to Channel 2, then you have no trigger signal. You need a trigger signal, so don't do that! Set the scope to trigger off Channel 1 if your signal is going into Channel 1.

It is possible to get the trigger level set incorrectly without knowing it. If your signal never gets above 5 volts and the trigger level is at 20 volts, then you can spend a lot of time wondering why you can't see your signal.

Assignment

1) Generate the sine wave for 50Hz, 4 volts peak to peak using function generator and view the output in Oscilloscope.

2) Generate the square wave for 100Hz, 1.5 volts using function generator and view the output in Oscilloscope.

3) Generate the triangular wave for 1kHz, 2.5 volts using function generator and view the output in Oscilloscope.


Experiment No.03

Using Multimeter to measure Voltage, Current and Resistance

Objective: To measure voltage, current, and resistance using the Multimeter provided in the lab and Verify theoretically calculated results using basic network laws. Equipments and components:

Variable Power Supply Multimeter Resistors

Schematic diagrams:

An ammeter measures current, a voltmeter measures the potential difference (voltage) between two points, and an ohmmeter measures resistance. A multimeter combines these functions and possibly some additional ones as well, into a single instrument.

The following diagrams show a multimeter can be used to measure current, voltage and resistance:


Procedure: 1. To measure current, the circuit must be broken to allow the ammeter to be

connected in series. Ammeters must have a LOW resistance

2. To measure potential difference (voltage), the circuit is not changed: the voltmeter is connected in parallel. voltmeters must have a HIGH resistance

3. An ohmmeter does not function with a circuit connected to a power supply. If you

want to measure the resistance of a particular component, you must take it out of the circuit altogether and test it separately.

Assignment: Measure the resistance using color coding and also measure voltage and current of the circuit given theoretically, implement the hardware and simulate the circuit using Pspice. Compare the results and verify them.

R1

R?

V15Vdc


Experiment No.04

Voltage Divider design and Verification of Ohm’s law and Kirchhoff’s voltage law

Objective:

To design Voltage Divider circuit using the given resistor and verify Kirchhoff’s voltage law theoretically, implement the hardware and simulate the circuit for the same using Pspice and compare the results.


12-volt battery Resistors Breadboard Connecting Leads Multimeter

Schematic diagram:

Procedure

1. Connect the three resistors in series, and to the 6-volt battery, as shown in the illustrations. Measure battery voltage with a voltmeter after the resistors has been connected to it.

2. Use Ohm's Law (I=E/R) to calculate circuit current, and then verify this calculated value by measuring current with an ammeter.

3. The measured value of current should agree closely with your Ohm's Law calculation. Now, take that calculated value for current and multiply it by the respective resistances of each resistor to predict their voltage drops (E=IR). Switch multimeter to the "voltage" mode and measure the voltage dropped across


each resistor, verifying the accuracy of your predictions. Again, there should be close agreement between the calculated and measured voltage figures.

4. Verification of Kirchhoff's Voltage Law: Use the numbers 0 through 3 is shown here in both illustrative and schematic form.

5. Using a digital voltmeter measure voltage drops around the loop formed by the points 0-1-2-3-0. Write on paper each of these voltages, along with its respective sign as indicated by the meter.

6. These figures, algebraically added ("algebraically" = respecting the signs of the numbers), should equal zero. This is the fundamental principle of Kirchhoff's Voltage Law: that the algebraic sum of all voltage drops in a “loop” adds to zero.

Result:

Thus the current divider circuit is designed, the output are obtained and verified by comparing the result with simulation output.

Lab Sheet Format:

1. Title 2. Objective 3. Equip. and Comp. 4. Circuit Diagram ( with values) 5. Details

a. State Kirchhoff’s Voltage Law b. Given Data c. Formulae Used d. Calculations e. Answers

6. Hardware Results a. Resistance b. Voltage across resistors c. Current

7. Simulation Results


a. Plot 1 (V1,V2,V3) b. Plot 2 (V, I, P) c. Output File

8. Result


Experiment No.05

Current Divider design and Verification of Ohm’s law and Kirchhoff’s current law

Objective: To design Current Divider circuit using the given resistor and verify Kirchhoff’s current law theoretically, implement the hardware and simulate the circuit for the same using Pspice and compare the results.


Voltage Source Resistors Multimeter Breadboard Connecting leads Pspice Programming

Schematic diagram:

Procedure

11. Connect the three resistors in parallel to and each other, and with the 12-volt battery, as shown in the illustrations. Measure battery voltage with a voltmeter after the resistors have been connected to it, noting this voltage figure on paper as well.

12. Measure voltage across each of the three resistors. 13. Use Ohm's Law (I=E/R) to calculate current through each resistor, and then verify

this calculated value by measuring current with a digital ammeter. 14. Calculate the power delivered by the source.


15. Measure current for each of the three resistors, comparing with the current figures calculated previously.

16. Measure total circuit current. 17. Note both the magnitude and the sign of the current as indicated by the ammeter.

Add this figure (algebraically) to the three resistor currents. 18. Disconnect the battery from the rest of the circuit, and measure resistance across

the parallel resistors. 19. Divide the battery voltage (previously measured) by this total resistance figure,

you should obtain a figure for total current (I=E/R) closely matching the measured figure.

20. The ratio of resistor current to total current is the same as the ratio of total resistance to individual resistance.

21. Design and simulate the circuit in OrCAD Pspice and generate the output for voltage, current flowing through each elements, and the power delivered by the source.

Result:

Thus the current divider circuit is designed using the given resistor, the values are calculated theoretically and, the results verified by comparing the them with hardware and simulation output.

Lab Sheet Format:

9. Title 10. Objective 11. Equip. and Comp. 12. Schematic Diagram 13. Details

a. State Kirchhoff’s Current Law b. Given Data c. Formulae Used d. Circuit Diagram ( with values) e. Calculations f. Answers

14. Simulation Circuit 15. Output

a. Plot 1 ( I1, I2, I3) b. Plot 2 (V, I, P) c. Output File

16. Result


Experiment No.06

MESH ANALYSIS

1. Find the current i1 for the circuit shown in Figure by using mesh analysis. Use PSpice to analyze the circuit and to generate output file and plot of the voltage i versus t.

Objective:

(i) To analyze the given circuit and find current i1 using mesh analysis theoretically.

(ii) To analyze the circuit and generate the output using Pspice. (iii) To verify the result by a hardware.

Equipments:

1. Resistors 2. DC voltage source – 12V, 5V 3. Multimeter 4. Connecting Wires 5. Breadboard 6. Pspice programming.

Circuit Diagram:

Procedures:

22. Connect the three resistors with each other, and with the Voltage source and Current source, as shown in the illustrations.

23. Set the voltage source as 6volts and current source as 5amps 24. Measure battery voltage with a voltmeter after the resistors have been connected

to it, noting this voltage figure on paper as well.


25. Measure the current flowing through each of the three resistors and the current i1 using nodal analysis.

26. Verify this calculated value by measuring current with a digital ammeter. 27. Switch OFF the supply and disconnect the circuit. For Pspice Simulation

1. Assembling of the electric circuit using Pspice software. 2. Changing the value of the part according to the electric circuit shown in the

figure. 3. Setting up the parameters. 4. Simulate the circuit.

Note: It is important to find the direction of flow of current Direction and Magnitude of current

(a) If the current flowing direction is same as to the source, then the magnitude of current is positive (+). (b) If the current flowing direction is opposite to source, then the magnitude of current is negative (-).

Lab Sheet Format:

11. Title 12. Objective 13. Equip. and Comp. 14. Circuit Diagram 15. Procedure 16. Circuit Diagram ( with values) 17. Calculation

a. Given Data b. Formulae Used c. Calculations d. Answers

18. Output Plot 19. Hardware Output 20. Result


Experiment No.07

SOURCE TRANSFORMATION

Objective:

(iv) To analyze the given circuits theoretically using source transformation technique

(v) To analyze the circuit and generate the output using Pspice. (vi) To verify the result by comparing with simulation output and hardware

results Equipments and Components:

7. Resistors 8. Power Supply 9. Breadboard 10. Connecting Wires 11. Pspice programming

Circuit Diagram:

24Vdc

3

Figure 1

5Adc

6

Figure 2

Procedures:

28. Convert the circuits shown in Figure 1 and 2 using source transformation technique.

29. Design and simulate the circuits using Pspice. 30. Compare and verify the calculated results with simulation output.

Result:


Thus the source transformation technique has been studied by analyzing various circuits. The simulation and hardware results are compared with theoretical calculation and verified. Lab Report Format:

1. Title 2. Objectives 3. Equipments and Components 4. Procedure 5. Circuit Diagram 6. Calculation 7. Hardware results (if available) 8. Simulation results 9. Result

Assignment

1. Apply source transformation technique to determine voltage across resistor R1

R3

2V3

12R6

8

R5

4 I2

3Adc

R4

3

0


2. Apply source transformation technique to determine the voltage across resistor R1 and current flowing through it for the given circuit. Implement the hardware and verify the results.

R4

2k

R1

1k

R2

220

V28Vdc

V110Vdc

0

R3

470

3. Apply source transformation technique to determine voltage across resistor R1 and current flowing through the circuit.

0

R1

3

R3

5

V115VdcI1

3Adc


Experiment No.08

SUPERPOSITION THEOREM

Objective:

(vii) To analyze the given circuit theoretically and find voltage v using superposition theorem.

(viii) To analyze the circuit and generate the output using Pspice. (ix) To verify the result by a hardware.

Equipments:

12. Resistors 13. Power supply 14. Multimeter 15. Breadboard 16. Connecting wires 17. Pspice programming.

Circuit Diagram:

v

0V

R1

8

+

0

R2

4I1

3AV1

6V

-

Procedures:

31. Calculate the voltage across the resistor for the given circuit using superposition technique theoretically.

32. Connect the three resistors with each other, and with the Voltage sources as shown in the illustrations.

33. Set the voltage source values as shown in figure. 34. Measure battery voltage with a voltmeter after the resistors have been connected

to it, noting this voltage figure on paper as well. 35. Measure the voltage across the resistor R1 using multimeter. 36. Switch OFF the supply and disconnect the circuit. 37. Simulate the circuit using Pspice 38. Verify this calculated value with simulation results and hardware outputs.


2. Find voltage across resistor R1 for the circuit shown in Figure by using the superposition theorem. Use PSpice to analyze the circuit and to generate output file and plot.

V120Vdc

R3

3

R1

2

I1

8Adc

R2

5

3. Find voltage across resistor R1 for the circuit shown in Figure by using the

superposition theorem. Use PSpice to analyze the circuit and to generate output file and plot. Implement the hardware and obtain the output.

R3

470

V38Vdc

0

R2

220

V212Vdc R1

1k


Experiment No.09

Transient Analysis of RC Circuits 4. Find the voltage vc(t) for t<0 and t>0 in the circuit shown in Figure1. Use PSpice

to analyze the circuit and to generate output file. Objective: To study the transient response of the given RC circuits. Equipments and Components:

18. Capacitor. 19. Resistance. 20. Timer switch. 21. DC voltage source. 22. Pspice programming.

Procedures:

5. Assembling of the electric circuit using Pspice software. 6. Changing the value of the part according to the electric circuit shown in the figure

below. 7. Setting up the transient parameters. 8. Simulate the circuit.

Circuit Diagram:

V1

24Vdc C1

20m

R2

9

R3

1

R1

3 U1

t=01 2

Figure 1


5. Find the voltage vc(t) for t<0 and t>0 in the circuit shown in Figure2. Use PSpice

to analyze the circuit and to generate output file.

C1

1/6

R2

12

R3

4

V1

24Vdc

U1

t=01 2

R1

6

Figure2

Lab Report Format:

1) Title 2) Objective 3) Equipments and Components 4) Circuit diagram 5) Calculation 6) Simulation Results


Experiment No.10

Transient Analysis of RL Circuits 6. Determine the inductor current i(t) for both t0 and t0 for each of the circuits

in Figure1 and Figure2.

Objective: To study the response of the given RL circuit. Equipments:

1. Indictor. 2. Resistance. 3. Timer switch. 4. DC voltage source. 5. Pspice programming.

Procedure:

1. Assembling of the electric circuit using Pspice software. 2. Changing the value of the part according to the electric circuit shown in the figure

below. 3. Setting up the transient parameters. 4. Simulate the circuit.

Circuit Diagram:

R8

2 U3

01 2

R10

12

R11

16

V440Vdc

R9

4

0

L2

2H

1

2


Figure1 R8

2

R11

4

V424Vdc

U4

0

1

2

R9

2

0

L2

2H

1

2

Figure 2

7) Title 8) Objective 9) Equipments and Components 10) Circuit diagram 11) Calculation 12) Simulation Results


Experiment No.11

MEASUREMENT OF POWER IN AC CIRCUITS

Objective:

(i) To analyze the given circuits theoretically and calculate the power. (ii) To analyze the circuit and generate the output file using Pspice.

Equipments:

23. Pspice programming. Circuit Diagram:

0

V1150Vac

0Vdc

R1

12

L1

10j

1 2

R2

8

C1

6j

Procedures:

39. Calculate the power for the circuit theoretically. 40. Assemble the given electric circuit using Pspice software. 41. Change the value of the parts according to the electric circuit shown in the figure. 42. Setting up the parameters. 43. Simulate the circuit. 44. Compare the output of the simulation with the calculated values and verify the

result.

Result: Thus the power calculation for the given circuit is studied and simulated.


Experiment No.12

MEASUREMENT OF POWERFACTOR FOR R, RL, RC CIRCUITS

7. Find the powerfactor R, RL and RC circuits shown in Figure A, B and C respectively. Use PSpice to analyze the circuit and generate plots of the voltage v versus time and current i versus t.

Objective:

(i) To analyze the given circuits theoretically and find the powerfactor. (ii) To analyze the circuit and generate the output file using Pspice.

Equipments:

24. Resistors 25. Capacitor 26. Inductor 27. AC voltage source – 220V, 50Hz 28. Pspice programming.

Circuit Diagram:

R1

1 Ohm

0

V1

FREQ = 50Hz

VAMPL = 220V

Figure A. R Circuit

Note: Use VSIN as voltage source


R1

1k

L1

1mH

1 2

V1FREQ = 50HzVAMPL = 220V

0 Figure B. RL Circuit

R1

1

C1

1uF

0

V1

FREQ = 50HzVAMPL = 220V

0 Figure C. RC Circuit

Procedures:

45. Connect the resistor with the Voltage source as shown in Figure A. 46. Calculate the powerfactor for the circuit theoretically. 47. Assemble the given electric circuits individually using Pspice software. 48. Change the value of the parts according to the electric circuit shown in the figure. 49. Setting up the parameters. 50. Simulate the circuit. 51. Compare the output of the simulation with the calculated values and verify the

result. 52. Repeat the above procedure to find the powerfactor for RL and RC circuits.

Powerfactor: It is defined as the cosine of the phase difference between voltage and current. The value of powerfactor ranges between zero and unity. Powerfactor (pf) = cos


R Circuit:

For a purely resistive load, the voltage and current are in phase, so that 0 iv . Therefore, the powerfactor is 10cos The power factor of purely resistive load is unity. RL Circuit: For an inductive load, the current lags voltage by 900, so that 90 iv . Therefore, the powerfactor is 01cos The power factor is lagging for inductive load. RC Circuit: For a capacitive load, the current leads voltage by 900, so that 90 iv . Therefore, the powerfactor is 01cos The power factor is leading for capacitive load. Result: Thus the power factor R, RL, RC circuits are studied and simulated.


Experiment No.13

KIRCHHOFF’S LAW IN FREQUENCY DOMAIN

8. Find voltage v(t) and current i(t) for the circuit shown in Figure applying kirchhoff’s law. Use PSpice to analyze the circuit and to generate output file .

Objective: (i) To analyze the given circuit theoretically and find voltage v(t) and current

i(t) using kirchhoff’s law. (ii) To analyze the circuit and generate the output file using Pspice.

Equipments:

29. Resistor - 5Ω 30. Capacitor – 0.1F 31. AC voltage source – 10V 32. Pspice programming.

Circuit Diagram:

+

-

Vs10cos4t

i

C0.1F

R

5 ohm

v

Procedures:

53. Connect the resistor and capacitor with the Voltage source as shown in the illustration.

54. Calculate the voltage v(t) and current i(t). 55. Assemble the given electric circuit using Pspice software. 56. Change the value of the parts according to the electric circuit shown in the figure

below. 57. Setting up the parameters. 58. Simulate the circuit.


Setting the parameters

(a) Select Pspice and click new simulation profile. (b) Create new simulation and select AC sweep as analysis type to obtain output file. (c) Calculate the frequency for the given circuit, and enter the same as start

frequency, and end frequency in sweep type, enter total points as 1. Calculations:

Given:- Vs = 10sin4t , therefore 4 Vs= 0010

f 2 , therefore Hzf 636.024

The impedance is

Cj

RZ1

= 1.0*4

15j

= 5-j2.5Ω

Hence the current

ZVsI =

j2.5-5010 0 = 22 5.25

)5.25(10 j

= 1.6+j0.8 = A057.26789.1 The voltage across the capacitor is

1.0*4

57.26789.1 IZcV0

jCjI

= V43.6347.4904.0

57.26789.10

0

Simulation Circuit:


AC = y esMAG = y esPHASE = y es

R1

5

IPRINTPHASE = y esMAG = y esAC = y es

C1

0.1

V110Vac0Vdc

0 Output File: ** Profile: "SCHEMATIC1-ac test" [ C:\orcad\ac test-schematic1-ac test.sim ] **** AC ANALYSIS TEMPERATURE = 27.000 DEG C ****************************************************************************** FREQ IM(V_PRINT1)IP(V_PRINT1) 6.360E-01 1.789E+00 2.659E+01 **** 10/03/08 13:13:59 ********* PSpice 9.2 (Mar 2000) ******** ID# 1 ******** ** Profile: "SCHEMATIC1-ac test" [ C:\orcad\ac test-schematic1-ac test.sim ] **** AC ANALYSIS TEMPERATURE = 27.000 DEG C ****************************************************************************** FREQ VM(N00236) VP(N00236) 6.360E-01 4.476E+00 -6.341E+01 JOB CONCLUDED Result :


Assignment:

1. Find voltage v(t) and current i(t) for the circuit shown in Figure applying kirchhoff’s law. Use PSpice to analyze the circuit and to generate output file.

5 sin 10t 0.2H

1

2

4

1. Find voltage v(t)) for the circuit shown in Figure applying kirchhoff’s law. Use PSpice to analyze the circuit and to generate output file.

5H

1

2

20 cos (4t-15)

60

10mF

Key: (A) FREQ IM(V_PRINT1)IP(V_PRINT1) 6.360E-01 1.789E+00 2.659E+01 FREQ VM(N00236) VP(N00236) 6.360E-01 4.476E+00 -6.341E+01

(b) V = 2.236 sin(10t+63.43) V, I = 1.118 sin(10t-26.57)A

(c) FREQ IM(V_PRINT3)IP(V_PRINT3) 6.366E-01 1.715E-01 -7.403E+01 FREQ VM(N05099) VP(N05099) 6.366E-01 1.715E+01 1.597E+01


Source

Fundamentals of Electric Circuits, III Edn, Sadiku

(1) Example 9.9 – Page No. 389

(2) Exercise 9.9 – Page No. 389

(3) Example 9.11 – Page No. 394

Electric Circuits Lab Manual

Documents

lab sheet

lab report

purely resistive

source transformation

dc voltage

orcadac test

current flowing

current divider