What is the purpose of a capacitor?

A capacitor serves the purpose of storing electrical energy. It does this by accumulating charge on its plates when a voltage is applied across it. Once the capacitor is charged, it can release this stored energy back into the circuit when needed, which is critical in various applications such as smoothing out fluctuations in power supply, filtering signals, and providing bursts of energy for devices that require a rapid discharge of electrical energy.

In the context of electrical circuits, while other components may conduct current, isolate circuits, or influence voltage levels, the primary function of a capacitor specifically lies in its ability to store energy for later use. This characteristic is what distinguishes capacitors from other electronic components and is fundamental to their function in both AC and DC circuits.