What is the purpose of a capacitor in an electrical system?

A capacitor plays a crucial role in electrical systems by storing electrical energy temporarily and helping to regulate voltage. This component can charge and discharge, providing a way to manage voltage fluctuations and maintain stable power levels in a circuit. For instance, in power supply circuits, capacitors help smooth out voltage peaks and dips, ensuring that devices receive a consistent voltage.

Additionally, capacitors are essential in filtering applications, where they can block direct current (DC) while allowing alternating current (AC) to pass, thus playing a key role in signal processing.

The other options do not accurately reflect the main function of a capacitor. While some components transform voltage levels, provide grounding, or increase current capacity, these are not the primary functions associated with capacitors. Instead, capacitors are specifically designed for energy storage and voltage regulation, making the choice of storing electrical energy temporarily and regulating voltage the correct explanation of their purpose.