emitter n collecter current........

Discussion in 'General Electronics Chat' started by ashutosh tiwari, Apr 7, 2010.

  1. ashutosh tiwari

    Thread Starter New Member

    Mar 19, 2010
    8
    0
    i wanna bjt we som time assume collecter current equal to the emittr n why some time not.......
     
  2. Engr

    Member

    Mar 17, 2010
    114
    5
    In terms of Ic you have this formula: Ic = Ib * B
    where B = beta and Ib = base current.
    In terms of Ie you have this formula: Ie = Ib + Ic
    where Ic = collector current and Ie = emitter current
    If the 1st equation is substituted to the 2nd equation in terms of Ic you will have this equation Ie = (Ic/B) + Ic

    Extracting Ic you will have this equation Ie = Ic((1/B) + 1)

    Typically B = 100 so ((1/B) + 1) is approximately equal to 1

    With this Ie is also approximately equal to Ic.

    Hope this helps.....
     
  3. kkazem

    Active Member

    Jul 23, 2009
    160
    26
    Hi all,
    I just wanted to say to Engr, excellent analysis, your spot-on.

    Regards,
    Kamran Kazem
     
    ashutosh tiwari likes this.
  4. ashutosh tiwari

    Thread Starter New Member

    Mar 19, 2010
    8
    0
    thanks alot.......................
     
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