The potentiometer is a resistance element with three lead-out terminals and the resistance value can be adjusted according to a certain change rule. The potentiometer is usually composed of a resistor and a movable brush. When the brush moves along the resistor body, the resistance value or voltage that has a certain relationship with the displacement is obtained at the output end. 　　

The potentiometer can be used as a three-terminal component or a two-terminal component. The latter can be regarded as a variable resistor, because its function in the circuit is to obtain an output voltage that has a certain relationship with the input voltage (external voltage), so it is called a potentiometer. The resistor body of the potentiometer has two fixed ends. By manually adjusting the shaft or the sliding handle, changing the position of the moving contact on the resistor body will change the resistance value between the moving contact and any fixed end, thus changing The magnitude of voltage and current.