TECH 150
LAB #3
ELECTRONIC DEVICES AND CIRCUITS
THE DIODE AS A RECTIFIER
Name _____________________
Introduction
One of the most important applications of the diode is in the conversion of AC to DC, a process
called RECTIFICATION. Electronic circuits require a DC source, usually a low voltage from about
3V to 50V, although a few require higher voltages. We will examine the “half wave” rectifier
and the “full wave rectifier” in this lab.
Equipment Required
Parts kit, 12.6 VCT transformer
Procedure: Part A – Half Wave Rectifier
1. Set up the circuit shown using a function generator for the source voltage VS. Set the
function generator to 10 V P-P at 100 Hz. Connect the red lead of the scope to VOUT and the
black lead to ground to measure the output or load voltage.
2. Sketch Vout, measure and show on the diagram the exact peak voltage with respect to
ground (use the DC coupling setting of the scope).
Vout (Pk) = _______________
Vout
0 Volts
3. What is the frequency of the load voltage waveform?
Procedure: Part B
freq = __________
Full Wave Rectifier – 2 diode circuit
4. This rectifier circuit will be connected to a 12.6 VCT transformer.
5. Connect channel 1 of the scope across the full transformer secondary voltage (Vs). Measure
it accurately and sketch the waveform showing the ± peak voltages. Set the scope on DC
coupling and put 0 V in the center of screen. The waveform may be slightly too large to
display. If this is the case use the Measure button on the scope.
VS (P-P) = __________________
+
Vs
0V
-
6. Calculate the RMS secondary voltage, VS, from your measured peak to peak value.
Calculated Vs,rms) = ________ {recall Vrms = VP_P/2√2}
7. Measure the RMS secondary voltage using the DVM set to AC volts.
Measured Vs,rms) = ________
Does this measured rms voltage agree with the 12.6 V transformer rating? Yes/No
If not why not
8. What is the frequency of the secondary voltage waveform?
Freq = __________
9. Connect two 1N 4005 diodes to the transformer secondary as shown to create a full-wave
rectifier circuit. Use a 1 kΩ resistor for the load.
10. Sketch Vout, measure and show on the diagram the exact peak voltage with respect to
ground (use the DC setting of the scope).
Vout (Pk) = _______________
Vout
0 Volts
11. What is the frequency of the full-wave rectified voltage waveform?
Freq = __________
12. Calculate the average voltage (the DC value) of Vout
Average Vout (Vout, DC ) = 2 x
Measure Vout using a DVM.
Vout, peak

=
__________
π
Vout, DC = _________
A DVM set to DC volts always reads the average value of a waveform
Signature __________________