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Insight - How Potentiometer works

Written By: 

Ashok Sharma

Potentiometer also known as pot is generally used in circuits to provide variable resistance or variable voltage. The heart of the potentiometer is a resistive strip inside it through which one can adjust the amount of resistance/voltage to pass in a circuit through it. Potentiometers are commonly used in circuits for various purposes like to control volume in audio circuits, to regulate the speed of the motor in a fan, as light dimmer, etc.

A potentiometer is shown in the images below.
Potentiometer, pot or variable resistor
Fig. 1: Image of a Potentiometer
Potentiometer, pot or variable resistor2
Fig. 2: Three Terminals of a Potentiometer


You can see there are three terminals on the potentiometer which are used to connect it to any external circuit.

Terminals of a potentiometer

Fig. 3: Metal Cap of Potentiometer 

The metal cap in the above image forms the outer covering and encloses all parts of the potentiometer.

Metal bearing of potentiometer

Fig. 4: Metal Bearing for Mechanical Connections

The metal bearing shown in the left side of the above image is used for mechanical connections.

Resistive Strip

Resistive Strip of potentiometer
Fig. 5: Internal Mechanism of Potentiometer
Resistance Strip in potentiometer or variable resistor
Fig. 6: Image Showing Concentric Circle of Potentiometer
You can see two concentric circles in the image above. The outer black arc (resistive strip) on the plate is the heart of the potentiometer. It is used to provide variable resistance to the circuit. The inner circle made up of a conductive material is connected to the middle terminal.

Conductive Brushes

Conductive Brushes of Potentiometer

Fig. 7: Stainless Steel Brush of Potentiometer

As shown in the figure, the brush, generally made up of stainless steel has two sections of dents. First one with three dents moves on the resistive strip and second one with two dents moves on the inner circle which is connected to the middle terminal (wiper).
The brush is attached to the shaft. It moves on the plate and the resistance applied to the circuit, depends on the position of the brush on the plate.

Variable Resistance Mechanism

Variable resistance Strip in potentiometer

Fig. 8: Image Showing the Entire Mechanism of Potentiometer

When we rotate the external shaft, the position of the brush varies accordingly. The resistance applied in a circuit depends on the position of the brush. The brush is designed so as to connect the resistive strip to the middle terminal via inner conductive circular metal plate which in turn is connected to the middle terminal of potentiometer at every instant.


thats up. now its very clear that how potentiometers work.

found it intersting too.



wow good


nice one:)


whats vcc and what pin is ground.