Capacitor Energy Calculator

A charged capacitor stores energy in its electric field.

How the Math Works

The Capacitor Energy Calculator uses the formula E = ½ C V² to determine the energy stored in a capacitor. Here, E represents energy in joules, C is capacitance in farads, and V is voltage in volts. The equation shows that energy increases with the square of voltage and linearly with capacitance. This relationship arises because work must be done to move charge onto the capacitor plates against the growing electric potential difference, with the ½ factor accounting for the average voltage during charging.

Practical Applications

This calculation is essential in designing electronic circuits, power systems, and energy storage solutions. Engineers use it to size capacitors for applications like power supply filtering, where capacitors smooth out voltage fluctuations, or in timing circuits where precise energy storage is critical. For example, in a camera flash, knowing the capacitor's stored energy ensures it can deliver a bright burst of light. It also helps in selecting appropriate components to prevent failure under high-voltage conditions or to optimize energy efficiency in battery-backed systems.

Day-to-Day Use

Understanding capacitor energy helps explain how everyday devices maintain functionality. For instance, when a smartphone powers off but the screen stays on briefly, capacitors provide temporary energy. In home electronics, capacitors stabilize power delivery, preventing surges that could damage appliances. Even in electric vehicles, capacitor energy calculations ensure efficient regenerative braking systems store and release energy effectively. Knowing this formula empowers users to make informed decisions about device longevity and energy use in modern technology.

Worked example

1000 µF at 12 V → 0.072 J.

FAQ