A temporary component of current and voltage in an electric circuit which has been disturbed. In ordinary circuit problems, a stabilized condition of the circuit is assumed and steady-state values of current and voltage are sufficient. However, it often becomes important to know what occurs during the transition period following a circuit disturbance until the steady-state condition is reached. Transients occur only in circuits containing inductance or capacitance. In general, transients accompany any change in the amount or form of energy stored in the circuit. After the following Introduction, transients in direct-current (dc) and alternating-current (ac) circuits with lumped elements are discussed. Transients of a more complex nature occur on distributed-parameter circuits, such as transmission lines. Such phenomena are elaborated upon in a separate section on transients in power systems. Finally, the modeling of transients in digital simulation is explained.