EGR 2201 Lab 5 Superposition
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NAME ______________________________ EGR 2201 Lab 5 Superposition OBJECTIVES: - To build and make measurements on a circuit with more than one voltage source. - To find out whether the superposition principle correctly predicts currents and voltages in such circuits. - To find out whether Kirchhoff's laws apply to such circuits. PROCEDURE: 1. Select the resistors shown in Data Table A. Measure and record their actual resistances. Throughout this lab, round all predicted values, measured values, and percentage errors to three significant digits. Data Table A: Resistor Values Resistor I.D. Nominal Value R1 560 ļ R2 1.2 kļ R3 1.2 kļ Actual Value 2. The diagram below shows a circuit with two voltage sources. The diagram also identifies three branch currents I1, I2, I3, and one node voltage vo that we wish to measure. EGR 2201 Lab #5 - Page 1 Revised 8/2/2016 3. In the space below, redraw this circuit with the 5-V source acting alone and the 7-V source “turned off.” Include component labels and values. Let’s call this Circuit 2. 4. Build Circuit 2 in Multisim, with ammeters and a voltmeter inserted at the proper places to measure the branch currents I1, I2, I3, and the node voltage vo. Obtain a printout of your Multisim circuit with the meters displaying values for these quantities, and attach it when you turn in the lab. Also record the Multisim values in the “Predicted” column of Data Table B. 5. On the blank breadboard diagram below, draw resistors (in pencil) showing how to build Circuit 2. Label the resistors as R1, R2, and R3. Also show the points where the trainer’s 5-V source and GROUND attach to the circuit. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. 6. Build Circuit 2 on a breadboard. Then measure the quantities listed in Data Table B, recording your measured values in the table. As always, round all values to three significant digits and include units with your values. Compute percentage errors, which should all be less than 5%. 7. Before proceeding, call me over to check your work. I will ask you to show me how to measure a quantity in the circuit. ____________________ Data Table B: Circuit 2 (with 5-V Source Acting Alone) Quantity Predicted Value (Multisim) Measured Value % Error I1 I2 I3 vo EGR 2201 Lab #5 - Page 2 Revised 8/2/2016 8. In the space below, redraw the original circuit again, but with the 7-V source acting alone and the 5-V source “turned off.” Include component labels and values. Let’s call this Circuit 3. 9. Build Circuit 3 in Multisim, with ammeters and a voltmeter inserted at the proper places to measure the branch currents I1, I2, I3, and the node voltage vo. Obtain a printout of your Multisim circuit with the meters displaying values for these quantities, and attach it when you turn in the lab. Also record the Multisim values in the “Predicted” column of Data Table C. 10. On the blank breadboard diagram below, draw resistors (in pencil) showing how to build Circuit 3. Label the resistors as R1, R2, and R3. Also show the points where the trainer’s 7-V source and GROUND attach to the circuit. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. 11. Build Circuit 3 on a breadboard. Then measure the quantities listed in Data Table C, recording your measured values in the table. As always, round all values to three significant digits and include units with your values. Compute percentage errors, which should all be less than 5%. Data Table C: Circuit 3 (with 7-V Source Acting Alone) Quantity Predicted Value (Multisim) Measured Value % Error I1 I2 I3 vo EGR 2201 Lab #5 - Page 3 Revised 8/2/2016 12. Using the superposition principle, combine your predictions from Data Tables B and C to predict the quantities listed in Data Table D for the original circuit (Circuit 1, on the first page of this lab). 13. On the blank breadboard diagram below, draw resistors (in pencil) showing how to build Circuit 1. Label the resistors as R1, R2, and R3. Also show the points where the trainer’s 5-V source, 7-V source, and GROUND attach to the circuit. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. .............................. 14. Build Circuit 1 on a breadboard. Then measure the quantities listed in Data Table D, recording your measured values in the table. As always, round all values to three significant digits and include units with your values. Compute percentage errors, which should all be less than 5%. Data Table D: Circuit 1 (with Both Sources Acting) Quantity Predicted Value (Superposition) Measured Value % Error I1 I2 I3 vo REVIEW QUESTIONS. Type your answers as part of your lab report. Use complete, grammatically correct sentences. 1. Based on your data for Circuit 1, is Kirchhhoff's Current Law satisfied in circuits having more than one voltage source? Explain, giving one specific example of how this law either is or is not satisfied in that circuit, using your actual (measured) values. As part of your answer, show your calculation, and discuss the percentage error between your actual values and the values predicted by KCL. LAB REPORT For this lab you will turn in a typed lab report, with your handwritten lab sheets stapled to the back. The course syllabus has instructions on how to format your lab report, along with a sample lab report. EGR 2201 Lab #5 - Page 4 Revised 8/2/2016
