In a circuit, what does a capacitor primarily store?

A capacitor primarily stores electrical energy in an electric field. This function arises from its basic design, which consists of two conductive plates separated by an insulating material called a dielectric. When a voltage is applied across the plates, positive and negative charges accumulate on each plate, creating an electric field between them. The energy is stored in this electric field and can be released when the capacitor discharges.

The ability of the capacitor to store energy is quantified by its capacitance, measured in farads. This stored energy can be utilized in various applications, such as smoothing out voltage fluctuations in power supplies, providing bursts of energy in flash photography, or coupling and decoupling signals in electronic circuits. This characteristic is fundamental to many electronic devices and circuits where quick release or absorption of energy is necessary.