Alexander Fufaev

Formula: Charging Capacitor

RC Circuit - charging capacitor Hover the image!

Capacitor voltage

Voltage across the capacitor (e.g. between the two capacitor plates). When charging the capacitor, this voltage increases exponentially with time \(t\). At the end of the charging process it reaches the value given by the source voltage \( U_0 \).

Source voltage

Source voltage is the constant voltage applied to the capacitor.


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 \( 1 \, \text{V} \).

Electrical Resistance

Resistor with the value \( R \) connected in series with the capacitor. The resistor has an influence on how fast the capacitor can charge.


After the source voltage \(U_0\) is applied, the capacitor starts to charge. The more time \(t\) has elapsed, the closer the capacitor voltage \( U_{\text C}(t) \) is to the value of the source voltage \(U_0\).