Potentiometers—simple electromechanical devices

Potentiometers—simple electromechanical devices that translate rotary or linear motion potentiometers into a change in resistance—have been a cornerstone of measurement, control, and position systems for more than a century. In a potentiometer, one terminal is hooked up to a voltage source and the second to ground. A third terminal connects a sliding contact called a wiper that runs across a resistive track. As the wiper is moved across the resistive track, the voltage changes, corresponding to the new position. This voltage change can be used to control anything from volume or light intensity to the movement of complex mechanical systems.