PWM Testing Equipment

[Ether]

Originally Posted by Ether

#1 You can use a free program like Audacity as a simple oscilloscope. Connect the PWM signal to the "line in" input of the sound card. Use a simple resistor voltage divider to reduce the signal voltage to 1 volt.

The above method is admittedly clunkier than a nice compact hand-held unit that gives a digital readout or an LED pass/fail indication, but it does have one advantage: You can see the actual waveform, and you can record the waveform over a period of time.

This means that in addition to measuring the pulse width, you can also:

- see any noise or improper waveform

- see what the period is, and if it is consistent

- see if there are intermittent dropouts

Plus it just might inspire a student or two. I still remember how inspiring it was the first time I built a simple RC circuit and saw the waveform on a glowing green oval CRT screen. It made physics come alive for me.