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Help Input output characteristics of BJT

  1. Jul 31, 2012 #1
    help!! Input output characteristics of BJT

    I have attached an image of the graph. Does this graph apply for both npn and pnp transistors. I have asked this because for pnp, the collector(c) and base(B) terminals must be reverse-biased at the active region, and B must be at a higher potential than C. Therefore, i think that for the active region Vcb is negative: Vcb= Vc-Vb <0 so Vbc must be positive. As shown in the graph, the transistor is in the active mode for Vcb>0. Why?

    For npn there is no problem. That's why I'm asking whether this graph applies for both npn and pnp. Please reply. Thanks!
  2. jcsd
  3. Jul 31, 2012 #2
    Re: help!! Input output characteristics of BJT

    i can't attach the pic so i'll jusr give the link
    http://comutronics.blogspot.com/2012/02/ece-basic-interview-question-and_06.html [Broken]
    Last edited by a moderator: May 6, 2017
  4. Jul 31, 2012 #3


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    Science Advisor

    Re: help!! Input output characteristics of BJT

    Correct for a pnp transistor.

    Presumably because they are showing the graph for a npn transistor.
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