How does a rheostat work?

Answer 1

A rheostat is simply a variable resistor. It is engineered so a "wiper" travels along the resistor carbon path. There is minimum resistance at one end of the path, and maximum resistance (what maximum value the engineers made into it) at the other end. Rheostats come in many values such as "0 to 1000 ohm", 0-1000 ohm, 0-10,000 ohm, and etc., all the way up to mega-ohm values. Some are designed to work on 0-5 watts, 0-20 watts, or larger power versions with resistance wire in them.

Answer 2

A rheostat is a simple variable resistor with two contacts. A resistor is a device designed to resist the flow of electricity. The more resistance an electronic current encounters, the more slowly that current flows. By increasing or decreasing the resistance in a circuit, a rheostat changes the amount of current flowing through that circuit.

Most rheostats contain a strip of some substance with fairly high resistance, such as carbon. One of the rheostat's two contacts attaches to the end of the carbon strip. The other moves along the strip as you adjust the rheostat slider or knob. When the sliding contact moves close to the fixed contact, the electric current only has to flow through a little bit of carbon to get from one contact to the other. This creates only a slight resistance. As the contacts get farther apart, however, the electricity has farther to travel along the carbon. This creates greater resistance, slowing down the current.