linear thermopile
Date1940-1950
Inventory Number1997-1-1654
ClassificationThermopile
Subject
Maker
Central Scientific Company
1889 - 2000
Cultural Region
Place of Origin
Dimensions21.6 x 15.2 x 2.8 cm (8 1/2 x 6 x 1 1/8 in.)
Material
Bibliography
DescriptionThe instrument is made of a white screen with a vertical slit in the center. Behind the screen is a box containing the thermocouples. Binding posts conduct the electrical signal produced by the couples to a galvanometer. The instrument is supported by a rod, which would have been set on an optical bench.
Signedon plaque, back: CENTRAL SCIENTIFIC CO.
FunctionAccording to the Cenco trade catalogue this device was designed for spectral energy measurements.
"In this apparatus we have mounted two standard units of iron-constantan thermocouples (20 junctions each or 80 junctions total) behind a slit in a metal screen. There are, consequently, 40 junctions exposed to the radiation which falls on the slit. The metal screen is finished in dull white, to receive a projected spectrum from any desired source. The couples are made of extremely fine wires, and the junctions are blackened. The lag is about 8 seconds. A difference in temperature of approximately 0.003 degree C between the warm and cold junctions will produce a deflection of 1 mm at a scale distance of 1 meter on No. 82070A Galvanometer. The screen is mounted on a 10 mm rod. Binding posts are provided for connection to the thermopile. The apparatus serves excellently as means for demonstrating the differences in energy radiated at different lengths in the spectrum."
For a general discussion of such an instrument, go to the following website.
"In this apparatus we have mounted two standard units of iron-constantan thermocouples (20 junctions each or 80 junctions total) behind a slit in a metal screen. There are, consequently, 40 junctions exposed to the radiation which falls on the slit. The metal screen is finished in dull white, to receive a projected spectrum from any desired source. The couples are made of extremely fine wires, and the junctions are blackened. The lag is about 8 seconds. A difference in temperature of approximately 0.003 degree C between the warm and cold junctions will produce a deflection of 1 mm at a scale distance of 1 meter on No. 82070A Galvanometer. The screen is mounted on a 10 mm rod. Binding posts are provided for connection to the thermopile. The apparatus serves excellently as means for demonstrating the differences in energy radiated at different lengths in the spectrum."
For a general discussion of such an instrument, go to the following website.
