We will be looking at a few circuits with combinations of Resistors, Capacitors and Inductors and their response to AC current.

The first is the RL series circuit.

We are familiar with complex numbers now. We find that the total impedance of this circuit is and the current is With the power factor being . Generally in a RL series circuit the current lags the voltage by an angle less than . If the resistance is very high compared to the inductive reactance the phase difference becomes negligble.