Hello all. I am currently trying to find the gain of a 2 stage amp. According to some notes I have, it is:(adsbygoogle = window.adsbygoogle || []).push({});

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.

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# Output gain of 2-stage amp.

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