# Homework Help: Complex Notation - Electrical Circuit

1. May 7, 2012

### amy1983

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

1 (a) using complex notation, find an expression for the output voltage, v0
1 (b) using complex notation, find an expression for the input current, ig, and hence determine the phase angle of ig relative to vg

2. Relevant equations

3. The attempt at a solution
See attached two attempts, in jpgs. I've gotten myself very confused!! If someone could advise that would be great.

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2. May 7, 2012

### Staff: Mentor

1.2 mH is not the same as 0.001 H; you've dropped a significant figure. This in turn has significantly altered your impedance value for the inductor, with the error propagating through your further calculations.

The input is specified as a voltage source, and you've treated it as a current. This is not correct.

You've then assumed that both the resistor and the inductor are conducting the entire "current" of 40A. They are in parallel so this is not possible; Parallel branches have the same potential difference, but not necessarily the same current. It's series components that have the same current.

3. May 9, 2012

### amy1983

Thank you gneill, i'll have to look at it and perhaps get a physics tutor.