What is a capacitor used for in electrical circuits?

A capacitor is primarily utilized in electrical circuits to store and release electrical energy. This function is crucial in various applications. When a capacitor is charged, it accumulates energy in the form of an electric field. This stored energy can be released when needed, making capacitors essential components in timing circuits, filters, and power supply systems.

For example, in a power supply, capacitors smooth out voltage fluctuations and provide bursts of energy quickly when necessary. This ability to release energy rapidly contributes to maintaining a stable and reliable supply in electronic devices. The charge and discharge cycle of a capacitor also enable it to filter signals in audio and radio applications, enhancing sound quality and signal clarity.

In contrast, the other functions listed in the options pertain to different components or principles in electrical engineering. Converting electrical energy into magnetic energy is a function of inductors, limiting current flow usually involves resistors or other protective devices, while increasing voltage levels is typically achieved through transformers. Therefore, the role of a capacitor is distinctly related to its capacity to store and release electrical energy.