What is the function of a rheostat?

A rheostat is a variable resistor specifically designed to control the flow of electric current in a circuit. By adjusting the resistance within the rheostat, you can increase or decrease the current that passes through it. This is essential in applications where one needs to fine-tune the brightness of lights or the speed of motors, as it allows for smooth and gradual changes rather than abrupt ones.

In systems where current regulation is vital, such as in dimming lights or controlling speed in motors, the ability to vary resistance makes the rheostat an invaluable component. When the resistance is increased, the current flowing through the circuit decreases, and when it's decreased, the current increases. Therefore, the primary function of a rheostat is to control current by providing variable resistance within the circuit.