Kohlrausch drum-type slide wire potentiometer
Date: circa 1920
Inventory Number: 1997-1-0171
Classification: Potentiometer
Subject:
Maker: Leeds & Northrup Company (1903 - 1995)
Owner: Chemistry Laboratory, Harvard College (founded 1850)
Cultural Region:
Place of Origin:
City of Use:
Dimensions:
22 × 28.2 × 23.4 cm (8 11/16 × 11 1/8 × 9 3/16 in.)
Material:
Description:
The instrument consists of a rectangular, raised wooden base, with a hard rubber top panel. On this panel is a large drum of hard rubber and metal, with a large handle on top for turning it. Lower edge of the drum has a numerical scale, and in front is a vertical glass rectangle on a metal frame containing a vertical scale (0-10 top to bottom). Central metal axle extends higher than the drum. There are Several electrical connectors on the panel behind the drum.
Signedon panel: THE LEEDS & NORTHRUP CO / PHILADELPHIA / 36783
Inscribedpaper label on panel: CHEMICAL LABORATORY OF / HARVARD COLLEGE / (handwritten text) R slide 29.3 ohms / [illegible] Feb 46
FunctionSlide wire resistances or potentiometers are a very precise form of variable electrical resistance. A long wire of metal is wound around a spool or drum, and the point of electrical contact with the wire varies as it is turned. This varies the electrical resistance. The scales on the drum and glass are to determine very precisely the length of wire that is currently active.
Such precise resistances were used to regulate and measure electrical currents.
Such precise resistances were used to regulate and measure electrical currents.
Curatorial RemarksFrom tag: "The slide wire has a resistor 1000 ohms on a plug at each end"
Another tag: "1921 From Chem Lab Dec 1980."
Another tag: "1921 From Chem Lab Dec 1980."
ProvenanceFrom the Chemical Laboratory, Harvard University, 1980.