Vol III - BJT - Bias Calculations missing assumption?

Discussion in 'Feedback and Suggestions' started by deBooglel, Nov 26, 2012.

  1. deBooglel

    Thread Starter New Member

    Nov 26, 2012
    1
    0
    Hi there,

    I could be wrong but in the section for the Bias Calculations using the collector feedback method the following is stated based on KVL:

    Vcc-IcRc-IbRb-Vbe = 0

    I think technically the voltage across Rc is (Ic + Ib)Rc, but as Ic is much much greater than Ib we can assume Ib is negligible. BUT this assumption was not stated and therefore technically the KVL equation is wrong!

    I might be wrong though!

    D
     
  2. Georacer

    Moderator

    Nov 25, 2009
    5,142
    1,266
    The assumption is stated, even if not explicitly. You can read I_c=(\beta +1) I_b \approx \beta I_c

    I guess it could be more clear, but then again, space and coherence is an issue.
     
  3. tshuck

    Well-Known Member

    Oct 18, 2012
    3,531
    675
    Look at line 1: I_{C}\approx I_{E}
    That is your assumption...
     
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