type K-3 Universal Potentiometer
Date: 1949-1958
Inventory Number: 2000-1-0039
Classification: Potentiometer
Subject:
Maker: Leeds & Northrup Company (1903 - 1995)
User: Department of Physics, Harvard University (founded 1884)
Cultural Region:
Place of Origin:
Dimensions:
17.5 × 48.9 × 31.8 cm (6 7/8 × 19 1/4 × 12 1/2 in.)
Accessories: includes a grey plastic dust cover with Leeds & Northrup logo in red
Description:
Potentiometer is comprised of a large metal box with several knobs on the top panel. These have labels such as: 'Aux EMF', 'Aux Pot', 'Galvanometer', 'range', 'SC', 'fine,' 'coarse, ' and 'GA sens.' An analog dial is labeled "Volt" and has a display of numbers that can be manipulated by turning the knobs. There are also two handles on both ends of the box. Instrument label includes Leeds & Northrup catalogue #7553.
Signedengraved: TYPE K-3 UNIVERSAL POTENTIOMETER / LEEDS & NORTHRUP CO. / PHILADELPHIA MADE IN U.S.A / CATALOG NO. 7553
FunctionA potentiometer is an instrument for measuring the potential (voltage) in a circuit against a standard cell. Before the introduction of the moving coil and digital volt meters, potentiometers were used in measuring voltage, hence the '-meter' part of their name. The method was described by Johann Christian Poggendorff around 1841 and became a standard laboratory measuring technique.
This information, and more, can be found on the following website.
This information, and more, can be found on the following website.
Historical AttributesBelonged to Harvard's Dept. of Physics as part of Prof. William Paul's group (also a member of the Dept. of Engineering and Applied Sciences) until donated to CHSI by Dr. Joseph Chen. (See instrument file for info from informal interview with Dr. Chen). Date range for first appearance on market: 1949-1958 [See also references to Type K potentiometer made by I. Melville Stein, "Measuring Instruments - a Measure of Progress..." 1958. (see instrument file)] Evidence shows that the K-3 was still widely used at least until 1960, when it was priced at $730.00 by the Central Scientific Co.
Curatorial RemarksValue information from Sphere Research Co. website; under "vintage electronic test equipment," has a picture and description of the K3, see the following link. See instrument file for a printout.