What is a Rheostat ?

A Rheostat is a variable resistor.  The term rheostat was coined by Sir Charles Wheatstone.  It comes from two Greek words. Rheos, meaning stream and Stat, implying a regulating device.

The Rheostat is used to limit the current in an electric circuit.  The Rheostat is mostly wirewound with a slider moving over it.  The Rheostat is used for speed control of motors and other electric devices.

The terms rheostat and the potentiometer are often used interchangeable.  In principle, they are similar.  However, there are some differences.  The rheostat has a higher wattage and current rating.  It is used for current control.  The potentiometer, on the other hand, is used to control voltage in circuits.  Its rating is also lower.