What does a capacitor store?

A capacitor is primarily designed to store electric charge. This makes it a fundamental component in electrical circuits, as it accumulates charge on its plates when a voltage difference is applied across them. When the capacitor is charged, it creates an electric field between the plates, which is where the energy is actually stored in the form of electric potential energy.

While it's true that a capacitor can also be associated with electrical energy and can influence voltage levels in a circuit, the core function of a capacitor is to store the electric charge itself. The ability to hold charge is what allows capacitors to perform various roles in electronic circuits, such as filtering, timing, and energy storage applications. Capacitors do not store magnetic fields; those are associated with inductors. Thus, focusing on the essential role of charge storage confirms the importance of electric charge in the context of capacitors.