Double Voltage - Capacitors & Stored Charge Step by Step

At fixed capacitance, stored charge is directly proportional to voltage. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Start with a base voltage

With capacitance 2 farads and voltage 6 volts, stored charge is 12 coulombs.

Q_{\text{base}} = 12\ \text{C}

Double the voltage

Keep the capacitance the same, but double the voltage to 12 volts.

V_{\text{changed}} = 2\cdot 6\ \text{V} = 12\ \text{V}

Charge doubles too

Because Q equals C times V, the stored charge doubles to 24 coulombs.

Q_{\text{changed}} = 2\ \text{F}\cdot 12\ \text{V} = 24\ \text{C}

The same direct rule keeps going

At fixed 2 farads, each voltage row maps directly to a charge row. Doubling is one row of the larger pattern.

\begin{array}{c|c|c}C&V&Q\\2\ \text{F}&6\ \text{V}&12\ \text{C}\\2\ \text{F}&12\ \text{V}&24\ \text{C}\\2\ \text{F}&24\ \text{V}&48\ \text{C}\\\end{array}