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Region of Operation of BJT

Discussion in 'Electronics Homework Help' started by BigBen10, Dec 19, 2012.

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  1. BigBen10

    BigBen10

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    Nov 11, 2012
    My lecturer has bn teasing us with this. In what region of operation will a BJT be operating when Vbe=0? i.e the emitter and base are shorted.Thanks 4 ur replies:)
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    How many regions of operation are there and what are they?

    What defines these?

    The correct answer will be clear.
     
  3. BigBen10

    BigBen10

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    Nov 11, 2012
    There are four regions. Forward active when Vbe>0 and Vbc<0, Reverse active when Vbe<0 and Vbc>0, Saturation when Vbe>0 and Vbc>0 and Cutoff when Vbe<0 adn Vbc<0.The above is for NPN. The question is a PNP BJT with Veb=0v and Vcb=-3v. The problem is non of the values Vbe's above a definite value(=0), they either greater than or less than.
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    Perhaps you should read the wikipedia entry for this:

    http://en.wikipedia.org/wiki/Bipolar_junction_transistor#Regions_of_operation

    The regions are not as clear-cut as you might imagine and you might want to read what it says specifically about operation close to where the be junction goes from forward to reverse bias.

    edit: if you look at it in terms of be current, it will also be clearer.
     
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