# Illustration Current-time graph - charging a capacitor

During the charging of the capacitor in a RC circuit, a current $$I(t)$$ flows and decreases exponentially from a value $$I_0$$ to zero:$I(t) ~=~ I_0 \, \mathrm{e}^{-\frac{t}{R\,C}}$
Here $$I_0 = \frac{U_0}{R}$$ is the maximum charging current at time $$t = 0$$.