Emitter, Collector, Transistors...?

Discussion in 'Homework Help' started by missfangula, Sep 20, 2010.

  1. missfangula

    Thread Starter New Member

    Sep 14, 2010
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    0
    Hello All,

    I am currently stuck on a circuits homework problem...the book is not much help, and I cannot find anything online similar to the circuit I am having to understand, so any insight is much appreciated.

    I have a circuit with two resistors, Rb, and Re, Rb connected to ground V and to transistor, and Re connected to the same transistor and to -15 V voltage source. The collector end of the transistor is connected to a +15 V.

    What is Vb, Ve, and Vc (base, emitter, and collector voltage drop)?

    Thanks in advance!

    -miss fangula
     
  2. Georacer

    Moderator

    Nov 25, 2009
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    1,266
    Is this a completely theoretical question, or it comes with numbers you forgot to provide?
     
  3. missfangula

    Thread Starter New Member

    Sep 14, 2010
    9
    0
    Sorry, beta = 180, Rb = 820 ohms, Re is 3.3 kOhms.

    Thanks again!
     
  4. missfangula

    Thread Starter New Member

    Sep 14, 2010
    9
    0
    Also, this is an NPN bipolar transistor.
     
  5. Georacer

    Moderator

    Nov 25, 2009
    5,142
    1,266
    First, let setup our set of equations:

    We have:
    I_E=\beta \cdot I_B \ and\\<br />
0=I_B \cdot R_B +0.7+I_E \cdot R_E -15\ \text{according to Kirchoff's Voltage Law for the mesh I have indicated}

    Do you understand on what ground I have written these equations? Can you solve the system yourself? As for the Vc, you can see for yourslef that it is connected to the voltage supply, making it 15V.
     
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