What is the function of a rheostat?

A rheostat is a variable resistor used to control and adjust the flow of electric current in a circuit.

Its primary function is to change resistance manually, which in turn regulates the current according to Ohm’s Law.

Key functions of a rheostat:

• Increases or decreases resistance in the circuit
• Controls current without changing the voltage source
• Used for adjusting brightness (in lamps), speed (in fans), or heating elements

A rheostat typically has a sliding or rotating contact, which changes the length of the resistive path, thereby varying resistance.

In summary:
A rheostat acts as a current controller by varying resistance in real time.