How does a capacitor function in an electrical circuit?

A capacitor functions by storing and releasing electrical energy, which plays a crucial role in stabilizing voltage levels within an electrical circuit. When a capacitor is charged, it accumulates electrical energy in an electric field between its plates. This stored energy can then be discharged when needed, helping to maintain a steady voltage supply and protecting the circuit from voltage spikes or drops.

This action is particularly important in applications such as smoothing out fluctuations in power supply, filtering signals in audio equipment, and providing quick bursts of energy to components like motors during startup. The ability of a capacitor to manage electrical energy in this way is foundational to its role in many electronic devices and electrical systems.

In contrast, the other options describe functions that do not accurately represent the core functionality of a capacitor within an electrical circuit. For instance, increasing electrical resistance pertains more to resistive components, while converting electrical energy into thermal energy relates to resistors or heating elements. Lastly, regulating frequency is a function of oscillators or filters, not the primary capability of a capacitor.