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Homework Help: Finding a Transfer Function using Laplace

  1. May 23, 2012 #1
    I'm trying to find the Transfer function of the circuit below so that I can draw the Bode plot for it. I chose to use Laplace because I think it made it a little simpler.
    7hRIx.png

    My equations so far:

    KVL of Left Loop: EQUATION1
    Vs=I1(900+1800)-900I2

    KVL of Right Loop: EQUATION2
    0=((2E6)/s+400+900)I2-900I1

    EQUATION3
    Vo=I2*(2E6)/s

    Rearranging EQUATION2 gives:
    I1=(1/900)((2E6)/s +1300)I2
    Substitute this back into EQUATION1 to get Vs in terms of I2 and s.

    When I do:
    H(s)= Vo/Vs
    I get:
    H(s)= 5000/(3(s+5000))

    Which I'm pretty sure is wrong.
     
    Last edited: May 23, 2012
  2. jcsd
  3. May 23, 2012 #2

    gneill

    User Avatar

    Staff: Mentor

    I think you'll want to check the math for your capacitor impedance; 1/(50E-6) is not 2E6.
     
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