DC Analysis - Saturation

Discussion in 'Homework Help' started by Schniz2, May 18, 2010.

  1. Schniz2

    Thread Starter New Member

    Apr 15, 2010
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    I need to complete a DC analysis of the attatched circuit, but i am not sure how to approach it because the transistor Q3 needs to operate in its saturation region for some of the input range. Is there a way to solve the Collector/Base currents of Q3 and Q4?
     
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
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    Were you given any other information - such as the transistor β values?

    Q5 & Q6 (in part) form a current mirror which controls Q3 & Q4 emitter currents.
     
  3. Schniz2

    Thread Starter New Member

    Apr 15, 2010
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    yep, im analysing for B=100.. ive changed my circuit design now... managed to make it out of a differential amplifier...
    i still have one of the transistors operating in saturation though... how do you find R_be of a transitor when you only know the saturation currents.. you cant really use (n*V_T)/(I_B) because I_B is huge compared to what it would be in the linear region.... or does the value of R_be actually change when the transistor goes into saturation?
     
  4. t_n_k

    AAC Fanatic!

    Mar 6, 2009
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    If this is a linear amplifier..???? (Yes or No?)

    Why do you want to operate in the saturation region?
     
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