I want to calculate the integral of a voltage pulse. I have designed this circuit to do the integration. I am using a non inverting integrator:
The op_amp_2 is the voltage pulse. Comp_1 is used to discharge the cap once the pulse has ended. So that the integral of each pulse can be found.
This is how the output looks like:
I wonder why the output falls down as the pulse ends. Is this because of the bias current of Op-AMP? I am specifically using a low bias (~pA) current opamp.
How can I avoid this?