What function does a potentiometer perform in a circuit?

A potentiometer is an adjustable resistor, which means its primary function is to vary resistance within a circuit. This capability allows it to control the flow of current and the voltage across components in the circuit. By turning the knob or sliding the control, the user can change the resistance and thus adjust the output voltage or current in a desired manner.

This makes potentiometers particularly useful in applications like volume controls in audio equipment or as variable voltage dividers. The other functions listed do not align with the role of a potentiometer; for instance, they do not directly boost voltage, measure current, or store energy, which are the specific roles of other components in electrical circuits.