- A resistor is a device which resists the flow of electricity. Most resistors have a set value, but variable resistors can be adjusted from a value of nearly "0" to a certain maximum value. By turning up or down the variable resistor, a used can increase or decrease the flow of electricity through a circuit. This makes variable resistors useful in controlling dimmer lights, volume knobs and many other types of circuits.
- A variable resistor is a strip of a material such as graphite which resists the flow of electricity. There is a fixed terminal attached to one end of the resistor. There is also a moving device touching the graphite called a wiper. When the resistor is adjusted, the wiper slides along the graphite, either towards or away from the terminal. When the wiper is close to the terminal, the electricity only has to flow through a little bit of the resistive material and the resistance is fairly low. When the wiper is further away, the electricity has to travel much further through it, and the resistance is much higher.
- Perhaps the most common type of variable resistor is the potentiometer, also known as a pot. The potentiometer is adjusted by turning a knob. Inside is a semicircular resistor strip with a terminal at either end and a wiper which rotates between them. As it moves towards one terminal, the wiper moves away from the other. This can be used to do things that normal circuits can't do. For example, if one terminal is the terminals are attached to different speakers, the potentiometer acts as a fader. As the resistance to one speaker increases, quieting it, the resistance to the other decreases, raising the volume.
