hi friends, i cannot understand the derivasion of OPAMP as an integrator. my book has suddenly replaced a term 1/s(where s=jw ) by an integral with time as variable, without any explanation. another thing is that if OPAMP can act as integrator, then why is it not THE BEST AMPLIFIER ON EARTH? because as you let time pass by, the output voltage goes on increasing without limit.......?? thanks.