What is the primary function of a capacitor in an electrical circuit?

The primary function of a capacitor in an electrical circuit is to store electrical energy. Capacitors are passive electronic components that can store and release energy quickly. They consist of two conductive plates separated by an insulating material called a dielectric. When a voltage is applied across the capacitor, an electric field forms between the plates, allowing it to hold a specific amount of electrical energy, known as capacitance.

In various applications, capacitors play crucial roles such as smoothing out voltage fluctuations in power supply circuits, coupling and decoupling signals in audio electronics, and timing applications in oscillators and timers. Their ability to quickly charge and discharge makes them essential for maintaining stable operations in circuits.

The other choices, while relevant to different components or materials, do not accurately describe the function of a capacitor. For instance, resistors are used to resist electrical current, diodes convert AC to DC, and amplifiers are designed to increase the strength of signals. These functions are accomplished through different types of components, each serving unique purposes within electrical and electronic systems.