I am trying to work on a design project and part of the overall circuit includes an Inverting Bistable Multivibrator using an OpAmp.
I have designed the circuit which is supposed to have a Upper/Lower Trigger point at +/-2 volts. As the circuit contains positive feedback, it is bound to saturate the output at L+/- of OpAmp. However my output seems to follow input with some gain instead of saturating.
Could someone explain what is wrong in the circuit and how can the desired functionality be achieved. I do not want to use non inverting bistable multivibrator ( and I have verified the saturation using non inverting) so as to keep the overall circuit polarity negative. Any help would be much appreciated if I can get a square wave (Green Trace) instead of triangular wave.
Following is the design schematic and the scope capture.
Best Answer
Your title is misleading - there is no bistable multi-vibrator in the circuit.
The circuit diagram as drawn has the op-amp shown with positive feedback, in this configuration it is a Schmidt trigger, which would give the output you want.
However, you have constructed the circuit with the +/- inputs (pins 2 and 3) the wrong way round - giving negative feedback. In this configuration the op-amp acts as a linear amplifier with a gain of 2 (1 + Rf/Rg)