Hello all. I am currently trying to find the gain of a 2 stage amp. According to some notes I have, it is: A = A1 x A2 x (rin2 / (rin2 + ro1)) Where A1 = gain of first stage A2 = gain of second stage rin2 = input resistance of second stage ro1 = output resistance of first stage Let p = (rin2 / (rin2 + ro1)) so that A = A1 x A2 x p I understand conceptually why 'p' comes in. It is due to loading of the stages together (right?). But I don't understand how to get that factor ('p') mathematically. Please explain. Thank you. PS: If a schematic of the amplifier is needed please let me know.