A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider.^[1] If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat.

The measuring instrument called a potentiometer is essentially a voltage divider used for measuring electric potential (voltage); the component is an implementation of the same principle, hence its name.

Potentiometers are commonly used to control electrical devices such as volume controls on audio equipment. Potentiometers operated by a mechanism can be used as position transducers, for example, in a joystick. Potentiometers are rarely used to directly control significant power (more than a watt), since the power dissipated in the potentiometer would be comparable to the power in the controlled load.

There are a number of terms in the electronics industry used to describe certain types of potentiometers:

• slide pot or slider pot: a potentiometer that is adjusted by sliding the wiper left or right (or up and down, depending on the installation), usually with a finger or thumb
• thumb pot or thumbwheel pot: a small rotating potentiometer meant to be adjusted infrequently by means of a small thumbwheel
• trimpot or trimmer pot: a trimmer potentiometer typically meant to be adjusted once or infrequently for "fine-tuning" an electrical signal