rheostat

Date1924-1936

Inventory Number1997-1-0423

ClassificationRheostat

Subject

Attributed to Hardwick-Hindle Company 1924 - ca. 1936

Cultural Region

Place of Origin

Dimensions15.5 x 55 x 12 cm (6 1/8 x 21 5/8 x 4 3/4 in.)

Material

DescriptionA device consisting of a cylinder of insulating material held horizontally by a black metal frame. Metal wire is wound around the cylinder very densely along the grooves. At both ends of the cylinder are large electrical connectors. Above the cylinder, also held by the metal frame, is a metal bar from on which slides a large electric contact that reaches down to touch the wire that goes around the cylinder. This contact can slide from one side of the cylinder to the other.

Signedunsigned

Inscribedmarked on plate: 40.7 Ohms / Max Amps 13

FunctionA rheostat functions as a variable resistance or as a voltage divider. If one end of the metal cylinder and the electrical contact that slides above are connected to a circuit, the rheostat works as a variable resistance. It can be altered by moving the point of contact on the cylinder's wire. If one connects the other end of the cylinder, the movable contact becomes a voltage divider: one can get from the movable contact any voltage between those at the two ends of the cylinder.