what is potentiometer
potentiometer has three terminals first and third terminal are connected to a resistive element which has different carbon composition.A resistive element is nothing but a potential wire which possesses some specific value of resistance.this resistive element mould like a circle. in between this, a shaft which is attached with a wiper type link which is rotates over the resistive element.this wiper type link is responsible to change in resistance and according to this voltage will also change.
construction is also shown in figure below.
TYPES OF POTENTIOMETER ACCORDING TO CONSTRUCTION
linear potentiometer is an instrument used to measure the potential different. it consist of 10meter wire of maganin or constantan which is stretched in ten segment each of one meter length.
principle of the potentiometer
it is basically consist of a battery and a potentiometer wire of 1m length . the positive and negative terminal of the battery are connected to the the ends A and B of the potentiometer wire.
if the balancing length is L then the potential different is equal to IRL
E = IRL
where E is the potential difference between AC length
I is the current flow through the primary circuit
L is the length between the A
here we can easily see that the current and the resistance is equal and only length of AC is changing so potential difference is directly proportional to the length.