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The last Beta and alpha for BJTs

  1. Mar 20, 2014 #1
    Thank you for any help that you can offer.

    Did I answer the questions?

    1. The problem statement, all variables and given/known data

    What is the minimum value of Beta which would cause a source? current source?

    https://scontent-a.xx.fbcdn.net/hphotos-prn1/t1.0-9/1959374_10151945917195919_465523700_n.jpg

    2. Relevant equations

    Beta = IC/IB

    IB = {(VB - VBE)/RE}
    ......................................................................
    IC = {[VCC - VC(sat)]/RC}


    3. Attempt at solving the problem

    Minimum Beta to cause a current:

    Beta = IC/IB

    IB = {(VB - VBE)/RE}
    ......................................................................
    IC = {[VCC - VC(sat)]/RC}
    .........................................................................
    IB = {(5 - 0.6)V/100kΩ}
    ......................................................................
    IB = (44uA)
    ......................................................................
    IC = (10 - 0.1)V/2kΩ
    .........................................................................
    IC = 4.95mA
    .....................................................................
    (IC)/(IB) = (4.95mA)/(44uA)
    .........................................................................
    (IC)/(IB) = 112.5 = β
    .....................................................................


    Are answers? Are there any errors located?

    Thanks again for your help.
     
  2. jcsd
  3. Mar 21, 2014 #2
    To be honest i don't quite understand your question. But I think that your answer is correct.
     
  4. Mar 21, 2014 #3

    NascentOxygen

    User Avatar

    Staff: Mentor

    Hi Duave. I think you are studying in a language that is not English? If that is so, then I recommend that you get the assistance of another student with the translation. We can understand your working and what it shows. We can't figure out what is meant by this question:

     
  5. Mar 21, 2014 #4
    Sorry It's a typo:

    What is the minimum value of Beta which would cause a saturation?
     
  6. Mar 22, 2014 #5

    NascentOxygen

    User Avatar

    Staff: Mentor

    In that case, your answer looks both appropriate and correct. :smile:
     
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