Thread: Seeing PWM Data
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Old 01-11-2019, 12:06 PM
andrewwynn's Avatar
andrewwynn andrewwynn is offline
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Seeing PWM Data

My fluke DMM has a duty cycle setting on the voltage setting that will get the results of PWM (it assumes positive so reads inverse for ground controlled pwm but you could hook up backwards).

Eg if pwm is on 80ms off 20ms it will read 80%. It doesn't show the details of the waveform just how long it's above vs below the average.

If you have a DMM that says "duty" on it that's the purpose.

The other quick and dirty test is an LED voltage tester. If the pwm control circuit can put out enough current to drive the led it will get dimmer and brighter to indicate the pwm control is lower and higher duty cycle.
E53 / M54 2001 3.0i gas LHD (pair of them: his & her)
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