stepped resistance box

Datecirca 1910

Inventory Number1997-1-0188

ClassificationResistance Box

Subject

Maker Leeds & Northrup Company 1903 - 1995

User Department of Physics, Harvard University founded 1884

Cultural Region

Place of Origin

Place of Use

Dimensions17.5 × 25 × 19.7 cm (6 7/8 × 9 13/16 × 7 3/4 in.)

Material

DescriptionStepped resistance box consisting of two pairs of brass terminals on opposite sides of top panel, one pair labelled "P.", other labelled "E.M.F". In the center of the panel is a brass switch with a knob that can be rotated to make contact at three different settings: 10, 100, & 1000 Ohms. These elements are mounted on a hard rubber panel over a rectangular mahogany box. The sides of box are perforated with small ventilation holes.

The small blue triangle indicates that this instrument was used in the Harvard University Physics 3 laboratory course in the late 1920s.

Signedon top panel: THE LEEDS & NORTHRUP CO. / PHILADELPHIA . / 6925

Inscribedfrom tag (written by DPW): Stepped Potentiometer Resistance Box c. 1900 [Tag also has a physical description of the instrument, a diagram of it, and a description of its inner workings.] terminals labeled: P and E.M.F. steps labeled: 10, 100, 1000

Curatorial RemarksThis model looks quite dated in style and technology, and does not appear in any of the collection's L&N catalogs (earliest dated 1912). DPW dates it c. 1900, though the blue triangle indicates use at Harvard in the 1920s.

FunctionSuch an instrument is used to measure the resistance of electric conductors. For a short general description and other images, go to the following website.

ProvenanceFrom the Department of Physics, Jefferson Laboratory Physics 3 rooms, Harvard University, 4-27-70.