The Operation of a Potentiometer

You can use a variable resistor, also called a potentiometer, to adjust voltage or current in an electronic circuit. Available in rotary and linear versions, a potentiometer contains a metal contact that moves along a strip of resistive material.

Track

• Inside the potentiometer, a part called the track produces electrical resistance. The track is made of carbon, conductive plastic, metal or other materials. The potentiometer's specified value is the resistance of the entire length of the track. Typical potentiometer resistances range from 100 ohms to 1 megohm (1 million ohms).

Wiper

• A polished conductive slider called the wiper rides on the track. Its position on the track determines the potentiometer's resistance, from nearly zero to the full specified value.

Terminals

• A potentiometer has three terminals to which you can connect wires. The wiper has a terminal, as does each end of the track. You can produce a variable voltage by connecting one wiper end to ground and the other to a voltage supply. The voltage at the wiper will be at ground, at the supply voltage or somewhere in between, depending on its position.