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Current Amplification Ratio

  1. Mar 2, 2014 #1
    1. The problem statement, all variables and given/known data
    If IB and IC (IB = Base current and IC = Collector current) of bipolar junction transistor are 1mA and 100 mA respectively, determine its current amplification ratio in common emitter configuration.

    2. Relevant equations
    Where β = current gain = [itex]\alpha[/itex]/([itex]\alpha[/itex]-1) (is this the same as current amplification ratio)???

    Where [itex]\alpha[/itex] = IC/IE (IE = Emitter current)

    3. The attempt at a solution
    I understand that whatever signal is input in through the base is amplified out through the collector.

    I found this page very helpful http://230nsc1.phy-astr.gsu.edu/hbase/solids/trans2.html#c6

    β = IC/IB = 100mA/10mA = 100

    Was this problem really that easy?! Or am I missing something big here? Professor usually assigns pretty involved homework problems.

    Thank you.
  2. jcsd
  3. Mar 2, 2014 #2


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    Staff: Mentor

    100 is right. Too easy?
  4. Mar 2, 2014 #3
    Well he usually give us problems where we have to derive our own equations to use. This one seemed too much like a plug and chug question considering that equation was all over the lecture and book. Thank you though!
  5. Mar 2, 2014 #4


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    Staff: Mentor

    The solution would have been slightly more challenging had you been told that it was the emitter current that was 100mA, determine β.
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