Equivalent resistance in a circuit

Discussion in 'Homework Help' started by Steve|, Nov 10, 2008.

  1. Steve|

    Thread Starter Member

    Nov 4, 2008
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    0
    Why is re = (rpi2+rb2)/(B+1) and not (rpi2+rb2||RC) ? Thanks.


    [​IMG]
     
  2. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    Can you post the initial circuit (i mean not the pi-model equivalent).
     
  3. Steve|

    Thread Starter Member

    Nov 4, 2008
    17
    0
    [​IMG]

    I'm actually not too sure why they left out Re either...
     
  4. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    They left out Re because you assume all the capacitors to be short circuits. Also, you cant say that re=(rpi2+rb2||RC) because there is a current source between them.
     
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