Need help in getting an expression for A for the loop gain AB(s)

Discussion in 'Homework Help' started by leoisleo, May 10, 2015.

  1. leoisleo

    Thread Starter New Member

    Jan 25, 2015
    10
    0
    Hi! In my task I'm supposed to draw a small signal model for a current amplifier realized with three steps (ASCE-CB-CE) and get an expression for the loop gain AB(s).

    I'm stuck at getting an expression for A for the loop gain AB(s) as the title states. Below I have picture of what I've done so far and if you see an error please tell me. Anyway I need to find an expression for ic3 in order to get an expression for A since A = ic3/v1 if you use the parameters in my model. So if you see in my calculations at the bottom I don't know how to go further because i'm stuck and would appreciate if anyone could help me with this? I'm also not sure where ic2 is supposed to go. Is ic2 = gm2v2?

    Thanks in advance!
    Photo 2015-05-10 11 39 52.jpg
     
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