reflecting galvanometer with moving coil
Date1900-1910
Inventory Number0163
ClassificationReflecting Galvanometer
Subject
User
Edwin H. Hall
1855 - 1938
User
Department of Physics, Harvard University
founded 1884
Cultural Region
Place of Origin
Place of Use
Dimensions57 x 18 x 18 cm (22 7/16 x 7 1/16 x 7 1/16 in.)
Material
DescriptionMoving coil suspended between brass covered electromagnets. Contained in a glass and wooden case surmounted by a brass suspension tube. Round brass base with 3 legs and leveling screws. Arranged for lower contact of a straight wire beneath damping disk. Similar to instruments 0164 and 0165. Black and white photos show scale that is missing in color photos.
Signedunsigned
FunctionReflecting galvanometers are used to measure very small electrical currents and voltage differences. Instead of having a scale with a pointer, in these galvanometers a small mirror turns in the presence of electrical currents. A coil of fine wire hangs between the poles of a magnet that generates a strong magnetic field. When an electric current is sent through the wires of the coil, the coil and the mirror attached to it are deflected. The change of angle can be detected by shining a light at the mirror and observing the reflection on a large scale that is placed in front of the device.
ProvenanceFrom the Department of Physics, Harvard University.
Historical AttributesThis instrument may have been used by Professor Edwin Herbert Hall, Harvard 1881-1919.
Siemens, Halske & Company
Date: 1858-1865
Object number: 0179d
Siemens, Halske & Company
Date: 1858-1865
Object number: 0179e
Siemens, Halske & Company
Date: 1858-1865
Object number: 0179a
Siemens, Halske & Company
Date: 1858-1865
Object number: 0179b
Siemens, Halske & Company
Date: 1858-1865
Object number: 0179c
American
Date: 1890-1930
Object number: 0155a,b,c,d
Leeds & Northrup Company
Date: circa 1910
Object number: 0549
Leeds & Northrup Company
Date: circa 1920
Object number: 0551
Leeds & Northrup Company
Date: circa 1920
Object number: 0550