Alexander Fufaev

Formula: Capacitor - Discharge Process (RC Circuit)

Current-time diagram during discharge of a capacitor

Discharge current

Unit
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

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

Capacitance

Unit
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

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

Time

Unit
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.