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# Illustration RC Circuit - discharging capacitor

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An electrical circuit with a capacitor of capacitance $$C$$ and a series resistor with resistance $$R$$. A specified source voltage $$U_0$$ is used to charge the capacitor when the switch is closed. If, on the other hand, the switch is opened, then the capacitor is short-circuited and discharges. It causes a discharge current $$I(t)$$ to flow through the circuit, which decreases exponentially.

The time-dependent voltage $$U_{\text C}(t)$$ is measured across the capacitor. This follows an exponential curve as the capacitor discharges:$U_{\text C}(t) ~=~ U_0 \, \mathrm{e}^{-\frac{t}{R\,C} }$