How to test pulse width modulator circuit without Oscilloscope

Discussion in 'General Electronics Chat' started by naitek, Jun 8, 2008.

  1. naitek

    Thread Starter Member

    May 31, 2008
    15
    0
    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
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    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.
     
  3. naitek

    Thread Starter Member

    May 31, 2008
    15
    0
    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
     
  4. Gadget

    Distinguished Member

    Jan 10, 2006
    613
    0
    Good thinking.
     
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