RE: Op-Amp Line Follower - Blog 1 First Steps

jc2048 — Thu, 14 Apr 2022 16:42:48 GMT

I was curious about your LM393 problem, so I thought I'd give it a try it.

The blue waveform is the voltage on the timing capacitor of a 555 circuit (this is all running on a 5V supply). The comparator is comparing it to half the supply. These are the comparator output transitions in more detail.

The pull-up resistor on the output was 10k.

That's all fast enough to 'slice' a waveform up to about a megahertz, or so.

I did think it might need a small amount of external hysteresis added, but it's quite clean without. For a noisier waveform you may need to add some.

So I'm not sure why your circuit is misbehaving. If the pull-up became disconnected it might behave strangely, depending what else you had it connected to.