A bjt

Discussion in 'Homework Help' started by JeromeDarshana, Sep 26, 2010.

  1. JeromeDarshana

    Thread Starter New Member

    Sep 17, 2010
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    I need to know a bipolar junction transistor which has an input impedence more than or close to 20 kOhms.:(
     
  2. Jony130

    AAC Fanatic!

    Feb 17, 2009
    3,962
    1,097
    Input impedance in BJT is depending on circuit configuration.
    For common-emitter Rin is equal
    Rin ≈ hfe * (26mV/Ic)
    And for common collector (emitter follower)
    Rin ≈ hfe * ( 26mV/Ic + Re).
    So for Rin> 20KΩ you need to use emitter follower circuit.
     
  3. JeromeDarshana

    Thread Starter New Member

    Sep 17, 2010
    11
    0
    thankz dude
     
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