What device is used to store electrical energy for short durations?

A capacitor is the device specifically designed to store electrical energy for short durations. It functions by accumulating charge on two conductive plates separated by an insulating material called a dielectric. When voltage is applied across the capacitor, electric charge builds up on the plates, allowing it to store energy in the electric field created between them.

The stored energy can then be released quickly, which makes capacitors useful in various applications such as smoothing out fluctuations in power supplies, providing bursts of energy in electronic circuits, or timing applications. Their ability to rapidly charge and discharge gives them an advantage in scenarios where quick energy release is essential.

In contrast, while inductors also store energy, they do so in a magnetic field and are more suited for applications involving continuous energy supply rather than short bursts. Diodes control the flow of current but do not store energy, and transistors are used as switches or amplifiers, also unrelated to the task of energy storage. This distinct capability of capacitors to store energy electrostatically is what makes them the correct choice in this context.