What is the primary function of a capacitor in electrical circuits?

The primary function of a capacitor in electrical circuits is to store and release electrical energy. Capacitors are passive components that can accumulate charge when connected to a voltage source. When the voltage is applied across the terminals of a capacitor, it stores electrical energy in the form of an electric field. This stored energy can then be released back into the circuit when needed. This capability allows capacitors to play critical roles in various applications, such as smoothing out voltage fluctuations in power supplies, filtering signals in audio equipment, and timing applications in circuits.

Capacitors do not amplify signals, which is the role of active components like transistors or operational amplifiers. They also do not primarily regulate voltage levels, although they can help in smoothing out voltage transients or AC signals; that function is more closely associated with voltage regulators. Lastly, while capacitors can contribute to energy conversion processes in combination with other components, they themselves do not convert energy from one form to another like inductors or transformers do. Their main utility lies in their capacity to store energy temporarily and release it, making them essential in many electronic applications.