Introduction to Pspice

Version 1.1 Page 1 of 3

Your Name ECE 201 – Lab 8 Sinusoidal Steady-State Analysis Date Completed

PRELAB 1. What would you expect the ratio of the resistances in the windings of your transformer to be? Explain.

° 2. If we choose to use Vi 10 as our reference for the circuit shown in Figure 1, will the

angle of V1 be positive or negative? Why?

° 3. If we choose to use Vi  10 as our reference for the circuit shown in Figure 1, will the

amplitude of V1 be larger or smaller than Vi? Why? 4. Suppose you have a 1 V power source at 1 kHz driving a speaker, but the sound produced is not loud enough. How could you use a transformer to increase the speaker’s volume? (Remember that the power produced by a speaker is related to the voltage applied to the speaker’s terminals.)

MAGNETICALLY COUPLED COILS 5. Use the oscilloscope to measure the amplitude of the voltages shown in Figure 1. Use the primary winding of your transformer as the inductor. Measure the phase of V1 with respect to Vi. Then use sinusoidal analysis to calculate the inductance of the primary winding of your transformer. Record the value in Table A. Repeat for the secondary winding of your transformer 6. Using sinusoidal analysis, estimate the mutual inductance of your transformer and enter this value in Table A. 7. Measure the inductance of each side of your transformer using the RCL meter. Record these values in Table A.

Primary Secondary Mutual Winding Winding Inductance L1 L2 M (H) (H) (H) 500 Hz

RCL Meter N/A

Table A. Transformer Coil Inductance

SPEAKER CHARACTERIZATION 8. What is the resistance of your speaker? 9. Record the inductance of your speaker at the specified frequencies in Table B. Speaker Inductance (H) 500 Hz

Table B. Speaker Inductance 10. Calculate the amount of power being delivered to the circuit with no compensation based on the amplitude of the voltage across the speaker and the speaker resistance. Record your results in Table C. 11. To boost the power delivered to the speaker, should you connect the primary or secondary winding to the speaker? Which winding should be connected to the function generator? 12. Based on measurements of the voltage amplitude across the speaker, how much power is delivered to the speaker with the transformer in the circuit? Record your results in Table C. 13. Draw below the complete circuit that you designed to maximize the power delivered to the speaker. 14. Calculate the amount of power being delivered to the speaker with the compensation circuit. Record your results in Table C.

Power Delivered to Speaker (W) Without Transformer or Compensation With Transformer With Compensation Circuit and Transformer Table C. Power Delivered to Speaker 15. Is there an audible difference between the volume produced in question 10 and 12? 16. Is there an audible difference between the volume produced in question 12 and 14? 17. Is there an audible difference between the volume produced in question 10 and 14?

OP-AMPS AND SPEAKERS 18. Does your circuit work? Why or why not? 19. Use the oscilloscope to capture a measurement showing the input voltage signal and output voltage driving the speaker. Paste a copy of the screen shot here.