What is a Variable resistor? Describe construction

 

What is a Variable resistor? Describe construction

Variable resistors are those resistors by which we can adjust the value of resistance

If we increase the resistance then the flow of current passing through the resistor is less and if we decrease the resistance value than the flow of current passing through the resistor is more.

For example, We all adjust the sound and brightness of our television set by turning the knob clockwise and anti-clockwise, these knobs are variable resistors . There are other names of variable resistors

1. Rheostats
2. Potentiometer

In electronics small variable resistors are generally used and that is called Potentiometer

Construction of variable resistor

The construction of all Potentiometer is basically the same

In a potentiometer the wire is wound over a dough shaped core. The shaft moves an arm and a contact point from end to end of the resistance element. There are three terminals coming out of a potentiometer. The outer two are the end-points and the middle one is the movable shaft.

Category

There are two types of Potentiometer

1. Linear
2. Non-linear

1. Linear – Linear potentiometer are those potentiometers whose height of the coil is uniform therefore the resistance can vary in the linear form
2. Non-linear – In Non-Linear potentiometer the height of the coil is not uniform and the output resistance is not in linear form.