Electric Circuits Lab Manual

Dh o f a r Un i v e r s i t y Sc hool of Engi neeri neering ng E l e c t r ic a l a n d Co C o mp mp u t e r E n gi g in e er e r in g D ep e p a r t me n t

El e c t r ic Ci Cir c u it it s L a b Lab Manu al P re reppare aredd B y,

Sheii k M oha mm She mme ed Su l t ha han n

Salalah, Sultanate of Oman

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CONTENTS

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















Calculations:

(a) (b) (c) (d) (e)

Define Ohm’s Law Given Data Formulae Used Calculation Answers

Result:

Thus the OrCAD Pspice has been studied by design and simulated simple electric circuit. Lab Sheet Format:

1. 2. 3. 4. 5. 6. 7. 8. 9.

Title Objective Equip. and Comp. Schematic Diagram Procedure Circuit Diagram ( with values) Calculation Simulation Circuit 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.

3 Ohms 10 A dc















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 time-var ying 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 sinusoida l 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 cable make sure you have it connected correctly.

















 

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 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 oscilloscop oscilloscopee 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 you can change the voltage level if you want. If you 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 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 level set incorrectly without knowing it. it. If your 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?

V1 5Vdc















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. Equipments and Components     

12-volt battery Resistors Breadboard Connecting Leads Multimeter

Schematic diagram:















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















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 O hm’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. Equipments and Components      

Voltage Source Resistors Multimeter Breadboard Connecting leads Pspice Programming

Schematic diagram:















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:















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)

(ii) (iii)

To analyze the given circuit and find current i1 using mesh analysis theoretically. To analyze the circuit and generate the output using Pspice. To verify the result by a hardware.

Equipments:

1. 2. 3. 4. 5. 6.

Resistors DC voltage source – 12V, 5V Multimeter Connecting Wires Breadboard Pspice programming.















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 (-).















Experiment No.07 SOURCE TRANSFORMATION

Objective: (iv)

(v) (vi)

To analyze the given circuits theoretically using source transformation technique To analyze the circuit and generate the output using Pspice. 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:

















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. 2. 3. 4. 5. 6.

Title Objectives Equipments and Components Procedure Circuit Diagram Calculation















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. R3

R2

470

220

V1 10Vdc

V2 R1 1k

R4 2k

8Vdc















Experiment No.08 SUPERPOSITION THEOREM

Objective: (vii)

(viii) (ix) Equipments:

To analyze the given circuit theoretically and find voltage v using superposition theorem. To analyze the circuit and generate the output using Pspice. To verify the result by a hardware.















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. R3

R2 5

3 V1 R1

I1

2

8Adc

20Vdc















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:

















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.















Experiment No.10 Transient Analysis of RL Circuits















Figure1 R8

R9

2

2 1















Experiment No.11 MEASUREMENT OF POWER IN AC CIRCUITS















Experiment No.12 MEASUREMENT OF POWERFACTOR FOR R, RL, RC CIRCUITS

























































































Electric Circuits Lab Manual

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