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

The role of a capacitor in an electrical circuit is primarily to store energy. Capacitors consist of two conductive plates separated by an insulator, or dielectric, which allows them to accumulate electrical charge when voltage is applied. When the capacitor is fully charged, it holds this energy, which can then be released back into the circuit when needed.

Capacitors play a key role in various applications such as smoothing out voltage fluctuations in power supplies, filtering signals in audio equipment, and timing applications in oscillators and timers. The ability to store and release energy quickly makes them essential for stabilizing and enhancing the performance of electrical circuits.

In contrast, other options like amplifying signals or increasing power refer more to the functionalities of different components like transistors, not capacitors. Similarly, the role of decreasing resistivity does not pertain to capacitors, as this involves the material properties and design of the conductors themselves rather than the capacitive action.