What is the primary use of a capacitor in electrical circuits?

The primary use of a capacitor in electrical circuits is to store and release electrical energy. Capacitors are components that can accumulate an electrical charge when voltage is applied across them and then discharge that energy when needed. This capability makes them essential for various applications, such as smoothing out voltage fluctuations, providing power during brief interruptions, and improving the performance of signals in circuits.

They are particularly useful in filtering applications, where they can stabilize voltage and prevent spikes that might damage sensitive components. By storing energy temporarily, capacitors can react quickly to changes in electrical demand, making them invaluable in power supply systems, timing circuits, and audio electronics.

This function is distinct from the roles of other components like diodes, which rectify current, or resistors, which can limit current flow, and it also differs from processes such as amplification, where transistors would be the key component. The correct understanding of a capacitor's role helps clarify its significance in the design and operation of various electronic systems.