Lr Circuit Time Constant. That is τ is the time it takes vl to reach v 1. T l r seconds.
R is the total circuit resistance and is measured in ohms. The time constant of an lr circuit is the time required to achieve 63 of the maximum current flowing through the circuit. In lr circuit this means build up of current when a voltage is applied.
However for a resistor inductor circuit the time constant is calculated from the quotient division of inductance in henrys over the resistance in ohms.
L is the inductance and is measured in henrys. This difference in calculation has a profound impact on the qualitative analysis of transient circuit response. In the first period of time τ the current rises from zero to 0 632 i0 since i i0 1 e 1 i0 1 0 368 0 632 i0. The larger the time constant the longer it takes for current to build up or decay in lr circuits or for capacitors to charge or discharge in cr circuits.
