Potentiometer Sensors

Abstract

A potentiometer, or pot for short, doesn’t change in resistance with temperature like a thermistor, or light level like a CdS light-dependent resistor. It changes with the rotation of a mechanical shaft. You’re probably already familiar with the device, because it’s commonly used as the volume control on audio equipment. Rotating the shaft changes the resistance between the center and outer two terminals. It’s a kind of self-contained voltage divider. Usually the shaft can only rotate 270 degrees, but multiturn versions are available. Figure 6-1 shows a few examples of potentiometers.