 The term "rheostat" is becoming obsolete, with the general term "potentiometer" replacing it.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.Where the rheostat must be rated for higher power (more than about 1 watt), it may be built with a resistance wire wound around a semicircular insulator, with the wiper sliding from one turn of the wire to the next.