Lab 2 Report

Part 1 – The half-wave rectifier

a.       Include a copy of the print out from your oscilloscope.

b.      Does the diode model with a constant voltage drop do a good job of modeling the behavior?  What is your proof?

Part 2 - AC to DC

a.       Include a copy of the oscilloscope printout showing Vin and Vout with the 0.1 uF capacitor

b.      Qualitatively explain what happened, and why, when the resistance was decreased.

c.       Qualitatively explain what happened, and why, when the capacitance was increased.

Part 3 - The Modulator

a.       How much smaller do you expect the output of the Wavetek generator to be with the headphones attached than when it is an open circuit?  (Hint: voltage divider).

b.      What did the modulated signal sound like?

c.       Why?

Part 4 - The Demodulator

a.       Show how you calculated the appropriate value for the capacitor.

b.      Verify that your circuit works by including a copy of the scope printout showing the modulated signal (Vin) and the demodulated signal (Vout).

Optional Sections follow

c.       Using the headphones, what was the frequency range over which the circuit seemed to work well when the carrier was 20 kHz?

d.      Over what frequency range did your circuit work when the carrier was 200 kHz?

e.       Explain why one is better than the other.

f.        Explain the purpose of the 0.1 uF capacitor in the second (and third) demodulator circuit.

g.       Verify that the op amp circuit has a gain of one (do this on paper, not by using the actual circuit).

h.       Explain why an amplifier with a gain of one is useful in this lab.

Make sure you include the name of all the people in your group on your report.