Need help on DC Biasing

Discussion in 'Homework Help' started by BlackMelon, Jun 6, 2016.

  1. BlackMelon

    Thread Starter Member

    Mar 19, 2015

    The problem statement is on the file "Bias Ask". After I've seen this, I quickly draw a small signal model of the whole circuit in the file "small signal ask", which allows me to consider this amplifier as "Series-Shunt" or "voltage to voltage" amplifier.

    The problem is not with the small signal circuit but the DC biasing. I need to know the DC collector current(IC) first so I can determine the "early resistance, ro". I set the vs=0V... And so what's next? How can I determine the IC since the 200uA is not emitter current? Can we consider the op-amp as an ideal one (V+ = V-) in DC biasing?

    Thank you
  2. Jony130

    AAC Fanatic!

    Feb 17, 2009
    Simply assume that Ic is 200μA.