Before starting this module, you should be able to:  When you complete this module, you should be able to: 
Note: Unless stated otherwise, discussions of inductive reactance in AC circuits assume a sinusoidal voltage source. 
The current through an inductor lags the voltage applied to the inductor by 90°

It is also
correct to say that the voltage applied to an inductor leads the current through the
inductor by 90° The 90° phase difference between current and voltage of an inductor applies only to ideal inductors—inductors that have no internal resistance. The internal resistance of realworld inductors causes the phase difference to be something less than 90°.
