Current in Electric Circuit/L, R in Series/Constant EMF at t = 0/Corollary 3

Theorem
Consider the electric circuit $K$ consisting of:
 * a resistance $R$
 * an inductance $L$

in series with a source of electromotive force $E$ which is a function of time $t$.


 * [[File:CircuitRLseries.png]]

Let the electric current flowing in $K$ at time $t = 0$ be $I_0$.

Let EMF imposed upon $K$ be zero.

The electric current $I$ in $K$ is given by the equation:
 * $I = I_0 e^{-R t / L}$

Proof
From Electric Current in Electric Circuit: L, R in Series: Constant EMF at $t = 0$:
 * $I = \dfrac {E_0} R + \paren {I_0 - \dfrac {E_0} R} e^{-R t / L}$

Setting $E_0 = 0$:

Hence the result.