op-amp --- input voltage Hello, I find op-amps very fun! And I understood mostly everything I was offered to study. But here is the thing. Why does the voltage has to be the same at the input leads? To be more specific. Lets say we have a inverting op-amp. And we have an imput Vin at -ive lead. +ive lead is grounded. Why are both then at 0 potential? Why can't -ive be at Vin and +ive at 0? Whats going on there? Does this has something to do with differential amplifier ?