Question

why rheostat is used in potentiometer?​

Answer 1

⊕ANSWER⊕

A rheostat is a variable resistor which is used to control current.

In contrast to potentiometers, rheostats have to carry a significant current.

Therefore they are mostly constructed as wire wound resistors.

Resistive wire is wound around an insulating ceramic core and the wiper slides over the windings

Answer 2

Answer:

The potentiometer is most sensitive when, at the balancing point, the slider or jockey is towards, but not too close to, the end of the potentiometer wire. The rheostat allows you to adjust the voltage across the potentiometer so that the balancing point is in the most sensitive region.