What does a capacitor do in a circuit?

A capacitor is a two-terminal electronic component that stores electrical energy in an electric field. It consists of two conductive plates separated by an insulating material known as a dielectric. When a voltage is applied across the plates, an electric charge builds up on each plate, allowing the capacitor to store energy. This stored energy can later be released into the circuit when needed, which is crucial for various applications, such as smoothing out voltage fluctuations, filtering signals, or providing bursts of energy.

In contrast, the other options describe functions that are not associated with capacitors. Converting electrical energy to light is a characteristic of devices like light bulbs or LEDs. Amplifying electrical signals typically refers to components like transistors or operational amplifiers. Reducing electrical resistance is usually related to resistors in a circuit or the use of superconductors, rather than the storage function of a capacitor. Thus, the primary role of a capacitor in a circuit fundamentally revolves around its ability to store electrical charge.