Potentiometer

A potentiometer is a device which uses three-terminal resistors with one contact, known as the wiper. The wiper slides across the device in order to create a variable voltage divider. When we use just two terminals connected, potentiometers behave like a variable resistor or a rheostat. In the model, we can observe terminals A and C connecting the power supply and terminals B and C connecting the light bulb. The resistive material inside of the potentiometer is often made of graphite though other common materials are used, including a resistance wire, carbon particles in plastic etc. In a linear potentiometer, the wiper moves along a linear material rather than a circular path. The final piece is the wiper. It acts as a third terminal (B) which moves over the resistive section of the device thereby changing the resistance on either side of it. As the wiper nears the A terminal, the voltage on the wiper terminal increases. It decreases as the wiper nears the C terminal. Changing the voltage affects the current flowing through the light bulb and changes its light intensity.