Which component is classified as a passive component in a circuit?

A capacitor is classified as a passive component because it does not require an external power source to operate; rather, it stores and releases electrical energy in the form of an electric field. Passive components, like capacitors, resistors, and inductors, do not amplify or control the flow of electrical energy; they interact with it without providing gain.

Capacitors are used in a variety of applications such as smoothing out voltage fluctuations in power supplies and filtering signals in electronic circuits. They are distinguished by their ability to store charge and influence voltage and current in passive roles.

In contrast, transistors, diodes, and amplifiers are considered active components because they require an external power source to operate and can control or amplify electrical signals. Transistors act as switches or amplifiers, diodes allow current to flow in one direction and block it in the opposite direction, and amplifiers increase the amplitude of signals. Each of these components plays a role that involves actively manipulating electrical energy rather than merely storing or passing it on.