Problems using an LM324 as a comparator ?

I'm using an LM324 to drive a MOSFET from a digital output from a microcontroller.

The microcontroller runs at 3.6VDC and thus the PWM pulse train is 0 to

3.3V. This is fed into the + terminal of one of the opamps on a LM324.

I generate a reference voltage of 1.8V and feed it into the negative input of the same op amp.

The LM324 is powered by a 13VDC supply.

The output of the op amp isn't changing. Its a steady 0V.

If I change the reference voltage to 0V, the output goes high, to nearly


Why isn't the op amp outputting a PWM pulse train ?


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google "LM324 oscillating"

-- Adrian C

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Adrian C

You should start by reconsidering your choice of device:

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