This is a rheostat attached to a wooden plank as a base. It consists of a hollow long cylindrical coil, mounted horizontally. Suspended above this there is a triangular metal rail along which a metal carriage can be slid. This has a plastic top, with a label on the top, and a rectangular base that drops to be within a centimeter of the coil. Beneath this there is a block of metal that contacts the coil surface. At both ends of the coil, brackets emerge perpendicularly; these have screw connectors that can be used to firmly attach electrical wires. The apparatus stands on metallic legs, two of which have been screwed into a short plank of wood.
Accession Number: 2019.ast.170
Alternative Name: Variable Resistor
Metal: Iron Alloy, Metal: Copper Alloy?, Plastic, Wood
On the label affixed to the top of the carriage: “MADE IN U.S.A.
CENTRAL SCIENTIFIC CO.
NEW YORK LOS ANGELES”
Length = 34.3, Width = 10.7, Height = 13.7
A rheostat can be used to adjust the resistance in a circuit smoothly and without interruption. The carriage can be slid along the coil to stop the current’s flow along the coil, thus decreasing on increasing the current.
Good: The rheostat is dusty and dirty, but all the pieces are present. The label on top of the carriage handle is quite worn in places, making the lettering difficult to read. This label is also somewhat warped against the nails that hold it in place.
Associated Instruments: 2019.ast.171
Manufacturer: Central Scientific Company (Cenco)
Date of Manufacture: Mid-20th Century; before 1968
This object was likely moved from the David Dunlap Observatory in Richmond Hill in 2008, upon the sale of the observatory. It was stored at the Department of Astronomy and Astrophysics until 2017, when it was moved to a new storage location in McLennan Physical Laboratories.
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