rheostat
Date1924-1936
Inventory Number1997-1-0419
ClassificationRheostat
Subject
Maker
Hardwick-Hindle Company
1924 - ca. 1936
Cultural Region
Place of Origin
Dimensions13.5 x 25 x 10 cm (5 5/16 x 9 13/16 x 3 15/16 in.)
Material
DescriptionA device consisting of a cylinder of insulating material held horizontally by a metal frame. A strip of metal is wound around the cylinder in a helical fashion from one end to the other. No turn ever touches the others around it. At both ends of the strip are electrical connectors. Above the cylinder, also held by the metal frame, is a metal bar from which hangs a large electric contact that touches the cylinder below on one side. This contact can slide from one side to the other.
Signedon slider: HH
Inscribedplate reads: .36 OHMS/ Max Amps 23
one number: 22
FunctionA rheostat functions as a variable resistance or as a voltage divider. If one end of the metal strip and the electrical contact suspended from the bar are connected to a circuit, the rheostat works as a variable resistance. It can be altered by moving the point of contact with the strip around the cylinder. If one connects the other end of the metal strip, the movable contact becomes a voltage divider.
Carl Zeiss Jena
Date: circa 1926
Accessories: wooden box with two hook-and-eye latches to fasten front opening; in instrument file: instruction book (photocopy); Geissler tube labeled "H2"; carboard tube containing German thermometer C in stainless steel holder that screws into instrument; glass bottle with cork stopper labeled "Monobromnaphthalin, Germany nD=1 658"; small round cardboard box labeled "For Pulfrich Refractometer" containing one tubulure
Object number: 1996-1-0229
Department of Physics, Harvard University
Date: mid 19th-late 19th Century
Object number: 0166
F. F. Metzger
Date: early 20th Century
Accessories: brown leatherbound wood case with purple stuffed velvet lining two metal locks in front;
steel rod contact points (4);
metal bar;
strain gauge;
card describing gauge ratio
Object number: 1999-1-0084
