What is the role of a capacitor in an electrical circuit?

A capacitor's primary role in an electrical circuit is to store electrical energy. When voltage is applied across its terminals, a capacitor accumulates charge, creating an electric field that holds energy. This stored energy can be released back into the circuit when needed, which is beneficial for various applications such as smoothing out fluctuations in voltage and providing bursts of power to components that require it briefly.

In practical scenarios, capacitors are used in filters, coupling and decoupling applications, power supplies, and timing circuits, among other functions. The ability to store and release energy efficiently makes capacitors essential components in both analog and digital electronic circuits.

While the other options describe functions associated with different components or concepts within electrical systems, they do not accurately describe the fundamental role of a capacitor. For example, measuring resistance pertains to the function of resistors or ohmmeters, current control typically involves devices like transistors or switches, and voltage regulation is more directly associated with voltage regulators or control circuits.