reflecting galvanometer with moving magnet
Date1890-1910
Inventory Number0159
ClassificationReflecting Galvanometer
Subject
Maker
Edelmann
fl. 1880 - 1920
User
Department of Physics, Harvard University
founded 1884
Cultural Region
Place of Origin
Place of Use
Dimensions86.4 x 25.5 x 19 cm (34 x 10 1/16 x 7 1/2 in.)
Material
DescriptionLarge stationary coil with heavy wire with two needles at the center above
the coils (6"). Bifilar suspension (missing) in brass tube. Coils contained in
black wooden box with cover glass for reflecting mirror (mirror is missing). Box held in brass framework pivoted on flat tripod base. Leveling screws missing. Black and white photos show scale that is missing in color photos. Circular graduated scale at top of brass tube.
the coils (6"). Bifilar suspension (missing) in brass tube. Coils contained in
black wooden box with cover glass for reflecting mirror (mirror is missing). Box held in brass framework pivoted on flat tripod base. Leveling screws missing. Black and white photos show scale that is missing in color photos. Circular graduated scale at top of brass tube.
Signedon cross arms supporting brass tube: EDELMANN / MÜNCHEN
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 scale placed in front of the meter.
ProvenanceFrom the Department of Physics, Harvard University, 11/6/56.
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: 0179d
Siemens, Halske & Company
Date: 1858-1865
Object number: 0179e
Siemens, Halske & Company
Date: 1858-1865
Object number: 0179c
American
Date: 1890-1930
Object number: 0155a,b,c,d
American
Date: circa 1915
Accessories: Extra case of coils and extra set of magnets (0154d). Three extra magnets (3 bar magnets and 2 bar magnets attached to an aluminum wire) are not numbered because of size.
Object number: 0154a,b,c
