How to test pulse width modulator circuit without Oscilloscope

Thread Starter

naitek

Joined May 31, 2008
15
Hello Everyone;

i have built a few pwm circuits now and i am a newbee at this stuff. I attached my drain(pc fac) to circuit and adjust my pot and the fan goes slow, medium to fast.

I have a voltmeter that can test frequency & hertz. Is there a way i can test or how can i test the circuit to make sure it is generating the proper signal.

thanks,

naitek
 

Wendy

Joined Mar 24, 2008
21,847
Assuming you have a signal, and the frequency is correct, the DC voltage on the output of the PWM will vary according to the PWM setting. The DC voltage, as measured by the meter, should be proportional to the PWM.
 

Thread Starter

naitek

Joined May 31, 2008
15
I created a jumper prope using 1000R & 100R resistors to connect to sound card, then using winscope saw my sawtooth on my lm324 IC and square wave on the comparator; : -))

yay.. Well, at least it looks correct. As i adjust my pot, the square pattern gets larger and smaller.

cheers
 
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