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Lab-in-a-Box
Experiment 23: Simulated Inductance
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Procedure
Analysis:
1. Derive the transfer function for the circuit in Figure 1(b) of the text.
2. Calculate the values of R1 and C1 so that the gyrator matches the RL filter in Figure 1(a) of the
text. Use only components in the parts list given in Appendix A of the text.
Modeling:
3. Simulate the RL circuit in Figure 1(a) of the text in PSpice. Use an AC Sweep to plot the
frequency response of the circuit from 1.0 Hz to 10 kHz. Make a printout of this graph, or copy
and paste it into your electronic laboratory notebook.
4. Using the Trace feature in PSpice, use the cursors to calculate the corner frequency of the circuit.
5. Simulate the gyrator circuit in Figure 1(b) of the text in PSpice. Use an AC Sweep to plot the
frequency response of the circuit from 1.0 Hz to 10 kHz. Make a printout of this graph, or copy
and paste it into your electronic laboratory notebook.
6. Using the Trace feature in PSpice, use the cursors to calculate the corner frequency of the circuit.
7. Comment on the similarities and/or differences between the curves generated in steps 3 and 5,
and the corner frequencies calculated in steps 4 and 6.
Measurements:
8. Construct the gyrator shown in Figure 1(b) of the text and simulated in step 5.
9. Connect the oscilloscope inputs with Channel 1 measuring the function generator output and the
Channel 2 measuring the filter output. Be sure to use proper attenuation on the scope input to
avoid saturating the soundcard input.
10. Set the frequency of the function generator to its lowest value (~67 Hz) and set the amplitude of
the function generator to 1 V. Record the magnitude and phase of the output signal.
11. Gradually increase the frequency of the circuit until the output reaches a maximum. Determine
the amplitude of the output at this point.
12. Set the voltage cursors at the -3 dB point from the signal maximum.
13. Decrease the input signal frequency from the maximum output until the signal just touches the
cursors. Record the frequency.
14. Comment on the significance of the measurement of step 13.
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15. Compute the percent deviation of the observed corner frequency from the design value computed
in step 6.
16. Plot the observed amplitude transfer function as a function of frequency. Compare this with the
PSpice simulation of the gyrator generated in step 5.
Last Revision 3.1: 9/25/2006
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