These equations show that a series RL circuit has a time constant, usually denoted τ = L / R being the time it takes the voltage across the component to either fall (across the inductor) or rise (across the resistor) to within 1 / e of its final value. That is, τ is the time it takes V to reach V (1 / e) and V to reach V (1 − 1 / e).
what is the time constant of rl circuit
τ = L / R being the time it takes the voltage across the component to either fall (across the inductor) or rise (across the resistor) to within 1 / e of its final value