Transient Response

Both electrical and electronic circuits may not always be in a stable or steady state condition, but can be subjected to sudden step changes in the form of changing voltage levels or input conditions. For example the opening or closing of an input switch or sensor.

However, whenever a voltage or state change occurs, the circuit may not respond instantaneously to the change, but may take an amount of time no matter how small if reactive components such as capacitors and inductors are present within the circuit.

The change of state from one stable condition to another generally occurs at a rate determined by the time constant of the circuit which itself will be an exponentially value. Then the time constant of a circuit defines how the transient response of the circuits currents and voltages are changing over a set period of time.