I would like to get a signal that is the mean value of a square signal going from 0 to 15 V using an integrator op-amp. Here is what I'm getting so far (the op-amp I have put is the UniversalOpAmp2):
For now I can only get an output voltage close to zero, here is a zoom showing that it oscillates very close to zero:
These things are really new to me so I'm probably missing some crucial points, maybe you could enlighten me?