Performance-Based Assessments for Semiconductor Circuit Competencies

I’ve used 0.47 μF capacitors and 1N4001 diodes with good success on a 10 volt AC (RMS) power supply. I recommend using low-capacity capacitors to minimize the amount of stored energy, since voltages in this circuit are potentially hazardous.

Any diodes will work for this, so long as the source frequency is not too high. I recommend students set the volts/division controls on both channels to the exact same range, so that the slope of the clipped wave near zero-crossing may seen to be exactly the same as the slope of the input sine wave at the same points. This makes it absolutely clear that the output waveform is nothing more than the input waveform with the tops and bottoms cut off.

An extension of this exercise is to incorporate troubleshooting questions. Whether using this exercise as a performance assessment or simply as a concept-building lab, you might want to follow up your students’ results by asking them to predict the consequences of certain circuit faults.

Any diodes will work for this, so long as the source frequency is not too high.

I have had good success with the following values:

V_source = 4 volts (peak)

f_source = 3 kHz

V_DC = 6 volts

C₁ = 0.47 μF

R₁ = 100 kΩ

Potentiometer = 10 kΩ, linear

D₁ = part number 1N4004 (any 1N400x diode should work)

An extension of this exercise is to incorporate troubleshooting questions. Whether using this exercise as a performance assessment or simply as a concept-building lab, you might want to follow up your students’ results by asking them to predict the consequences of certain circuit faults.