What does capitance alone do in the circuit?

Capacitance in a circuit primarily stores and releases electrical energy. It allows for the smoothing of voltage fluctuations, acting as a buffer by charging when voltage increases and discharging when it decreases. This property is crucial in applications like power supply filtering and timing circuits, where stable voltage levels are essential. However, capacitance alone does not provide energy; it must be part of a circuit with other components to be functional.