Homework Help: Finding impedance in an ideal transformer circuit

m453438 · Dec 18, 2009

1. The problem statement, all variables and given/known data
This is a review question for my test, but I can't get the right answer, the problem is to find the impedance ab.

2. Relevant equations
Zin = 1/a^2 * ZL

3. The attempt at a solution
The 10 ohm resistor and the capacitor are in parallel and then add the 50 ohm resistor times 1/9. Doing this, I get 60-0.333j, but it is not the correct answer.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

berkeman · Dec 18, 2009

m453438 said: ↑

1. The problem statement, all variables and given/known data
This is a review question for my test, but I can't get the right answer, the problem is to find the impedance ab.

2. Relevant equations
Zin = 1/a^2 * ZL

3. The attempt at a solution
The 10 ohm resistor and the capacitor are in parallel and then add the 50 ohm resistor times 1/9. Doing this, I get 60-0.333j, but it is not the correct answer.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

Challenging question! I'd approach it by writing the 3 KCL equations for the 3 nodes. Put an AC voltage source at the left feeding terminals ab, label the upper left of the xfmr "1", the bottom of the xfmr "2", and the upper right of the xfmr "3". Write those 3 KCL equations, and see if you can solve for the voltages and currents in the circuit. Once you have those, you should be able to solve for Zin = ______

m453438 · Dec 18, 2009

berkeman said: ↑

Challenging question! I'd approach it by writing the 3 KCL equations for the 3 nodes. Put an AC voltage source at the left feeding terminals ab, label the upper left of the xfmr "1", the bottom of the xfmr "2", and the upper right of the xfmr "3". Write those 3 KCL equations, and see if you can solve for the voltages and currents in the circuit. Once you have those, you should be able to solve for Zin = ______

Thank You!, I would never thought of that...

The Electrician · Dec 18, 2009

Have you made any progress?

If you already have the correct answer, what is it?

m453438 · Dec 19, 2009

The Electrician said: ↑

Have you made any progress?

If you already have the correct answer, what is it?

I haven't tried solving yet, but the correct answer according to my instructor should be 210 - j2700 ohms. And thank you everyone for helping me out.

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Homework Help: Finding impedance in an ideal transformer circuit

m453438

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berkeman

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m453438

The Electrician

m453438