Miller Theorem

Discussion in 'General Electronics Chat' started by VVS, Apr 20, 2009.

  1. VVS

    Thread Starter Active Member

    Jul 22, 2007
    Hello people,

    I am studying for analogue electronics atm and we studied the miller theorem (approximation) so in the BJT small signal model in Common Emitter configuration one can replace the capacitor between the base and collector by a scaled capacitor (1+gain of circuit without Capacitor) between the input and ground and a scaled capacitor (1+1/gain of cct without Capacitor between) output and ground.
    I understand how to use it and we have also got a kind of derivation of the theorem, but our lecturer told us that it is not a theorem it is an approximation.

    But I am not sure why it is an approximation?? :confused:
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009