type K-3 Universal Potentiometer
Date1949-1958
Inventory Number2000-1-0039
ClassificationPotentiometer
Subject
Maker
Leeds & Northrup Company
1903 - 1995
User
Department of Physics, Harvard University
founded 1884
Cultural Region
Place of Origin
Dimensions17.5 × 48.9 × 31.8 cm (6 7/8 × 19 1/4 × 12 1/2 in.)
Material
Accessoriesincludes a grey plastic dust cover with Leeds & Northrup logo in red
DescriptionPotentiometer 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
Curatorial RemarksValue information from Sphere Research Co. website; under "vintage electronic test equipment," has a picture and description of the K3, see the following <a href="http://www.sphere.bc.ca/test/vintage.html" target="_blank">link</a>. See instrument file for a printout.
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.
Leeds & Northrup Company
Date: circa 1920
Accessories: cover; instruction sheet inside of cover
Object number: 1997-1-0180
Leeds & Northrup Company
Date: circa 1948-1960
Accessories: vinyl cover
Object number: 1997-1-1131
Leeds & Northrup Company
Date: 1925-1935
Accessories: cover; instruction sheet inside of cover
Object number: 1997-1-0201
Leeds & Northrup Company
Date: circa 1930
Accessories: cover; instruction sheet inside of cover
Object number: 1997-1-0204
Leeds & Northrup Company
Date: circa 1926
Accessories: cover; instruction sheets inside of cover (2)
Object number: 1997-1-0205
Leeds & Northrup Company
Date: circa 1930
Accessories: mahogany cover with sheet of directions attached inside
Object number: 1997-1-0157
Edison Manufacturing Company
Date: circa 1894
Accessories: wooden case (0277a) with removable door (0277b); Edison certification on backside of door; fragment of broken inspection tag inside case reads "The Leeds"...
Object number: 0277a,b,c
Leeds & Northrup Company
Date: 1926-1929
Accessories: storage box
Object number: 1997-1-0227f
Leeds & Northrup Company
Date: 1935-1936
Accessories: storage box
Object number: 1997-1-0227a
Leeds & Northrup Company
Date: 1935-1936
Accessories: storage box
Object number: 1997-1-0227e
Leeds & Northrup Company
Date: 1935-1936
Accessories: storage box
Object number: 1997-1-0227b
Leeds & Northrup Company
Date: 1935-1936
Accessories: storage box
Object number: 1997-1-0227c