Topic summary
rheostat
Extracted from the Wikipedia article Potentiometer.
Rheostat
The most common way to vary the resistance in a circuit continuously is to use a rheostat. Because of the change in resistance, they can also be used to adjust magnitude of current in a circuit. The word rheostat was coined in 1843 by Sir Charles Wheatstone, from the Greek ῥέοςrheos meaning "stream", and -στάτης -states (from ἱστάναιhistanai, "to set, to cause to stand") meaning "setter, regulating device", which is a two-terminal variable resistor. For low-power applications (less than about 1 watt) a three-terminal potentiometer is often used, with one terminal unconnected or connected to the wiper.