Which electrical component is used to store electrical charge?

• A. Capacitor
• B. Inductor
• C. Resistor
• D. Transformer

Answer: (A)

A capacitor stores electrical charge by creating an electric field between two conductive plates separated by a dielectric. When voltage is applied, charges accumulate on the plates with opposite signs, so energy is stored in the field between them. The amount stored depends on the capacitance and the applied voltage. Capacitance increases with plate area and the dielectric’s ability to permit electric field (permittivity) and decreases with the distance between the plates. This is exactly what a capacitor is designed to do—hold charge for short periods and release it as needed. In contrast, an inductor stores energy in a magnetic field around a coil, a resistor dissipates energy as heat, and a transformer transfers energy via magnetic coupling rather than storing it as separated charge.