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Homework Help: Mutual inductance in a circuit.

  1. Nov 20, 2013 #1
    1. The problem statement, all variables and given/known data

    Derive TEC between terminals "ab".

    2. Relevant equations

    3. The attempt at a solution

    I figured I'd add the mutual inductances to the inductors, and solve it as a normal RLC circuit, since no current is passing through the 80j coil, it's inductance wouldn't change. The 50j coil becomes an 80j coil (50j + 30j) and the 40j coil becomes a 70j coil (40j + 30j). Setting the voltage source to zero yields a thevenin resistance of -60 + 60j and KVL yields to a Thevenin voltage of 9 + 41j volts. However the answer says Rth = 60 + 60j and Vth = 9 + 51j. Can anyone help me identify where I went wrong? Thank you in advance.

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    Last edited: Nov 20, 2013
  2. jcsd
  3. Nov 20, 2013 #2

    Andrew Mason

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    First of all you will have to explain the question. What does TEC stand for?

    Where do you take into account the capacitor?

  4. Nov 21, 2013 #3
    TEC stands for Thevenin Equivalent Circuit, and the capacitor does not undergo mutual inductance, so I use its phasor form to find the equivalent thevenin resistance like I would with a resistor.
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