Capacitors have the ability to store and discharge electrical potential energy. Which statement best describes this behavior?

• A. Capacitors store energy as magnetic energy.
• B. Capacitors convert DC to AC.
• C. Capacitors store and discharge electrical potential energy.
• D. Capacitors regulate voltage.

Answer: (C)

Capacitors store energy in the electric field between their plates. When connected to a voltage source, they accumulate energy by building up voltage across the plates. The stored energy is proportional to 1/2 C V^2, where C is the capacitance and V is the voltage. When a discharge path is provided, the electric field collapses and the stored energy is released as current. This ability to store and then release electrical potential energy is what defines their behavior. They don’t store energy as magnetic energy (that’s for inductors), they don’t convert DC to AC, and while they can help smooth voltage in a circuit, their primary description is storing and discharging energy.