# Homework Help: Impedance of practical Capacitor

1. Dec 9, 2013

### bigu01

A practical capacitor can be modeled by an ideal capacitor in parallel with a resistor.Find the impedance of practical capacitor at the radian frequency ω=377rad/s.Known C1=0.1 x 10^-6F R1=1 *10^6.

I am first determining the Z, by adding the impedance of resistor and the capacitor in parallel.
And I am getting Z1(377)=10^6/(1+j37.7)= 2.6516*10^4 ∠-1.519 However book solutions gives ∠-1.5443.I would like to get some help about where my mistake is,or how should I approach the question. I know that finding the angle we should do θ=arctan(y/x) where y is the imaginary part and x is the real part.Hope I was clear and did not complicate it.

2. Dec 9, 2013

### Staff: Mentor

I can confirm the solution of the book. How did you calculate -1.519? Maybe just a rounding error?

3. Dec 9, 2013

### bigu01

I was using the degree mode, I should have used the radian angle unit one

4. Dec 9, 2013

### Staff: Mentor

Don't post the same problem in multiple threads. I am closing this thread.