A potentiometer is a type of tool and fixing used to adjust the electrical resistance of a circuit by varying the position of a contact along a resistance element. It is commonly used as a variable resistor or a voltage divider in electrical circuits. When used as a variable resistor, the potentiometer may be adjusted to control current flow, amplify signals, or adjust the output voltage of a circuit. When used as a voltage divider, the potentiometer can provide a voltage level in between two reference voltages. Potentiometers can also be used to control or adjust the sensitivity or frequency of circuits or devices.