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

The function of a capacitor in an electrical circuit is to store electrical energy temporarily. Capacitors are passive components that can accumulate and release electrical charge, which allows them to serve several purposes in various applications. When a voltage is applied across the capacitor, it charges up and stores energy in the form of an electric field. This stored energy can be released back into the circuit when needed, making capacitors crucial in smoothing out fluctuations in power supply, filtering signals, and providing timing elements in circuits.

In contrast, the other choices pertain to functions not performed by capacitors. For example, providing resistance to current flow is a characteristic of resistors, not capacitors. Measuring current flow falls under the function of ammeters or other measurement devices. Finally, converting electrical energy into thermal energy is a function associated with resistors in the context of energy dissipation, but this does not apply to capacitors, which instead focus on energy storage and release.