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The University of New South Wales

School of Electrical Engineering and Telecommunications ELEC 2134: Laboratory 3

Superposition Theorem In this laboratory you will analyze a circuit using the superposition theorem.

1. (12 marks) Consider the circuit shown in Fig. 1. Preparation: You must understand the superposition principles before you arrive at the laboratory. The circuit you will test contains one ac supply voltage. The same principles apply to this circuit as to circuits with only dc voltages. You are required to find the voltage across the capacitor by measurement and simulation. You do NOT need to calculate the voltage across the capacitor. If you are not prepared you will be penalised up to 5 marks.

a) Build the circuit.

b) Use the oscilloscope to measure the voltage across the capacitor. Save the result.

c) Use the superposition theorem to find the voltage across the capacitor by measurement. Record all the steps and save all intermediate results. Compare with result from Step 1b) and comment.

Fig. 1

2. (8 marks) Build PSpice model of the circuit shown in Fig. 1.

a) Use PSpice to plot the voltage across the capacitor. Compare with the result obtained in Step 1b) and comment.

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b) Use PSpice and superposition theorem to find the voltage across the capacitor by simulation. Record all the steps and save all intermediate results. Compare with results from Step 1c) and comment.

(Total: 20 marks)