I've only shown a very small part of the circuit (if the rest of the circuit matters I can show the rest - diodes are used to maintain the charge acorss the capacitor).
The capacitor is constantly getting charged by the op-amp, i.e. the capacitor is initially at 0v, and keeps getting charged (without losing its charge) up to a peak value and it stays at the peak voltage. The peak value is determined by the power supply of the op-amp (In my case this is 15v).
What I've been trying to do (without much success) is find a way to discharge the capacitor to 0v (ground it, or just really close to ground) really quickly, and allow it to get charged up again, similar to a relaxation oscillator.
What I've Tried:
I've tried using a UJT, PUT, SCR, and interesting transistor combinations. I can always seem to ground the capacitor really quickly once it reaches a certain voltage, but I as do, it doesn't charge up again (I think it's because I also end up grounding the op-amp, but I'm not too sure). I can show them if need be.
It would be great if there was a way to discharge the capacitor once it reaches a certain voltage, and once it has been fully discharged, allow the op-amp to continue to charge it up again. Is this actually possible to achieve with this setup? Or is it inherently not possible? I'm hoping to try and find solutions using purely analogue components (transistors, capacitors etc)
Full Circuit (Simplified a bit)
It uses a diode pump to charge up the capacitor in steps.