A resistance of R draws current from a potentiometer. The potentiometer wire, AB, has a total resistance of Ro. A voltage V is supplied to the potentiometer. Derive an expression for the voltage across R when the sliding contact is in the middle of potentiometer wire.
When the slide is in the middle of the potentiometer, only half of its total resistance i.e. R0/2 (since resistance is directly proportional to length) will be between A and point of contact (C), say R1, will be given by the following expression.
The total resistance between A and B will be sum of the resistance between A & C and C&B i.e R1+R0/2
Current flowing through the potentiometer will be
The voltage V1 taken from the potentiometer will be the product of current I and the resistance R1
