Potentiometers are adjustable resistors. They can be either in the form of a sliding switch or a turnable knob. Internally there are two terminals connected by a tapered strip of resistant material and a third terminal, known as a 'wiper', which connects to it at a point set by adjusting the potentiometer, ranging from low to higher resistance. Potentiometers can be used to weaken a signal, to run part of a signal to ground, or to divide an input signal between two output signals.
The most familiar applications of potentiometers are in dimmer switches for adjusting lighting, and in the volume knobs used on audio equipment such as stereo systems, electric guitars and mixing desks.