Time Constant of an RL Circuit

The time constant τ of an RL circuit (a circuit consisting of a resistor and an inductor) is a measure of how quickly the current in the inductor rises to its maximum value after a voltage is applied. It is given by the ratio of the inductance L (in henrys) to the resistance R (in ohms). The time constant represents the time it takes for the current to reach approximately 63.2% of its final value during the charging phase of the inductor. This time constant also indicates how long it takes for the current to decay to 36.8% of its maximum value after the voltage source is removed.

Practical applications of this formula include predicting how an RL circuit will behave in electronic filters, surge protectors, audio equipment, and other devices where inductors are used to regulate current or voltage over time.