# Phase of curcuit

1. Dec 4, 2013

### scorpius1782

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

I have an AC RLC circuit with the inductor in series with parallel capacitor and resistor.

At what w is the emf in phase with the current?

2. Relevant equations

3. The attempt at a solution

I'm suppose to know this from a previous class but as a transfer student my classes never dealt with phase or RLC circuits. Any help would be phenomenal.

The question is specifically asking if $w=\frac{1}{\sqrt{LC}}$

2. Dec 4, 2013

### sandy.bridge

What exactly within an electrical system causes the phase of the current to differ from the phase of the voltage?

3. Dec 4, 2013

### scorpius1782

The inductor resists changes in current so voltage changes happen more quickly and vice versa at the capacitor. (I just discovered ELI the ICE man). So, would this mean that the peak would happen every 90 degrees? How would I relate the angle to w?

4. Dec 4, 2013

### sandy.bridge

The phase of the current will differ from the phase of the voltage if there is reactance present within the network. If the voltage and the current are completely in phase with one another, it implies that the load is completely resistive (imaginary portion of the impedance is zero). Do you know how to calculate the impedance of a capacitor and inductor?

5. Dec 4, 2013

### scorpius1782

I see you found my other post! I'll discuss this there.