Skip to main content

Formula Resistor-Capacitor Circuit Half-life    Electrical Resistance    Capacitance

Formula: Resistor-Capacitor Circuit
Voltage-Time Graph - discharging capacitor


Half-life is the time after which an initial value has decreased or increased by half. You can use the formula to calculate the half-life for charge, current or voltage on the capacitor.

For example, the capacitor is initially charged to \( 10 \, \mathrm{V} \). You discharge it. Then the half-life indicates the time after which the capacitor voltage has decreased to \( 5 \, \mathrm{V} \), that is to half.

Electrical Resistance

Resistance of an electrical resistor that is connected in parallel with the capacitor. The resistor is mostly used to make the discharge process faster or slower. The greater the resistance, the longer it takes for the initial value to decrease or increase to 50%.


Electrical capacitance of the capacitor. A capacitor with a large capacitance discharges more slowly than a capacitor with a small capacitance.