A potentiometer is a three-terminal resistor featuring a sliding or rotating contact that allows it to function as an adjustable voltage divider. When only two terminals are utilized—one end and the wiper—it operates as a variable resistor, or rheostat.

The device known as a potentiometer serves as a voltage divider for measuring electric potential (voltage), reflecting its name and design principle.

Potentiometers are frequently employed to control electrical devices, such as volume knobs in audio equipment. Additionally, when operated by a mechanism, they can serve as position transducers, as seen in joysticks. However, potentiometers are seldom used to directly manage significant power (over a watt), as the power dissipated in the potentiometer would be similar to that in the load being controlled.