Problem met on LM393
Posted: Fri Mar 03, 2017 9:00 am UTC
In the attached circuit, I have a comparator (LM393) that takes a sine wave (from pint "A") and produces a 5v square wave (at point "B"). Then it is fed to a limiter circuit to condition it for input to a TTL 3.3v micro.
When only the comparator circuit is present (i.e. other part not connected), I get a nice 5v square wave. But when I connect the second part of the circuit, the amplitude of the square wave at the output of the comparator itself is reduced to about half (and with some distortion).
Why is this happening? I have previously used the same second part of the circuit for conditioning all types of inputs to bring them down to 3.3v and worked fine but not here.