Quote:
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.
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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.