This lab explores the transient and AC behavior of capacitors and inductors.
Do the following exercises. Report your results by writing a Word document and submitting it in Isidore. Submit one report per group.
Component | Measured | Calculated |
---|---|---|
L1 | n/a | |
L2 | n/a | |
L1 + L2 | ||
L1 || L2 |
Use a function generator to produce a square wave and observe the signal on the oscilloscope. Adjust the frequency to produce a waveform something like the example below.
Display the frequency and rise and fall times on the measurement line. Capture at least one image to include in your report.
Calculate the time constant from the rise/fall times, trise = 2.2 τ. Also calculate the time constant τ = RC. Explain or discuss any differences between these calculations.
Use the oscillocope as before and display the frequency and rise and fall times on the measurement line. Capture at least one image to include in your report.
Calculate the time constant from the rise/fall times, trise = 2.2 τ. Also calculate the time constant τ = L/R. Explain or discuss any differences between these calculations.
In each of the following exercises you will need to record the following measurements from the oscilloscope.
Vary the frequency until the phase shift is 45° and record the AC response. The gain is the ratio of output amplitude voltage to input amplitude voltage (Vout / Vin).
component | Frequency | Vin | Vout | Ratio (gain) | Phase |
---|---|---|---|---|---|
L | |||||
C |
The frequency recorded above, and the measured value of the resistor can be used to calculate the capacitance or inductance. Verify this calculation by comparing to the value measured on the impedance meter.
component | calculated value | measured value |
---|---|---|
L | ||
C |
This is a resonant circuit. Adjust the frequency to give maximum output signal. Record the AC response (voltage and phase). Change the frequency higher and lower until the gain (ratio of output to input amplitude) has dropped to 0.707 of the peak gain. Repeat the measurement using a different resistance.
Frequency | Vin | Vout | Ratio (gain) | Phase |
---|---|---|---|---|
Frequency | Vin | Vout | Ratio (gain) | Phase |
---|---|---|---|---|
Case | R | L | C |
---|---|---|---|
1 | |||
2 |
Case | Measured | Calculated | ||||
---|---|---|---|---|---|---|
Resonant frequency | Bandwidth | Q | Resonant frequency | Bandwidth | Q | |
1 | ||||||
2 |
Maintained by John Loomis, last updated 22 October 2012