What type of component is primarily used to store electrical energy in a circuit?

A capacitor is primarily used to store electrical energy in a circuit. It consists of two conductive plates separated by an insulating material called a dielectric. When voltage is applied across the plates, an electric field is created, allowing the capacitor to store energy in the form of an electrostatic charge. This characteristic makes capacitors essential in various applications such as filtering, smoothing out voltage fluctuations, timing circuits, and energy storage in power supply systems.

In contrast, resistors do not store energy; they instead dissipate electrical energy as heat. Inductors store energy in a magnetic field created by the current flowing through them, but they operate based on different principles than capacitors. Transistors are semiconductor devices used for switching or amplifying electrical signals but do not function as energy storage components.