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Formula Capacitor - Discharge Process (RC Circuit) Discharge current    Capacitance    Electrical Resistance    Time

Formula: Capacitor - Discharge Process (RC Circuit)
Current-time diagram during discharge of a capacitor
RC Circuit - discharging capacitor
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Discharge current

The current that flows when the capacitor is discharged. The current does not drop to zero immediately, but reaches zero after a certain time.

Initial current

The current at time \( t = 0 \). Its value is given by the applied source voltage \(U_0\) and the resistance \(R\): \( I_0 ~=~ \frac{U_0}{R}\).


Electrical capacitance is a characteristic quantity of the capacitor and tells how many charges must be brought onto the capacitor to charge the capacitor to the voltage \( 1 \, \mathrm{V} \). The capacitance has an effect on how fast the capacitor can discharge.

Electrical Resistance

Resistor with resistance \( R \) connected in series with the capacitor. The resistance has an effect on how fast the capacitor can discharge.


At the time \(t = 0\) of the discharge process, the current has the value: \( I(0) = - I_0\). With time, the discharge current decreases to zero.