Phase angle

The phase angle is used to represent electrical impedance. It is the phase difference between the voltage applied to the impedance element and the current driven through it.　A time delay, or lag, takes place between the voltage across a circuit or an element and the current passing it. This is usually expressed as an angle where one-half cycle of a sine wave is represented by π (＝180°). The time lead/delay relation between two or more positions of an alternating current is discussed in terms of phase difference.