reflecting galvanometer with moving magnet
Date1890-1930
Inventory Number0250
ClassificationReflecting Galvanometer
Subject
Maker
American
?
User
Department of Physics, Harvard University
founded 1884
Cultural Region
Place of Use
Dimensions52.5 × 18 × 13 cm (20 11/16 × 7 1/16 × 5 1/8 in.)
Material
DescriptionGalvanometer with long string suspension with mirror (missing) and magnet hung between two coils. Coils contained in square black brass case with black brass suspension tube and mirror housing. Suspension tube has circular viewing window for mirror. Two pairs of binding posts on each side of case. Movable circular brass tripod base with three leveling screws.
The blue triangle found on the instrument indicates it was use in the Physics 3 course at Harvard in the late 1920's.
The blue triangle found on the instrument indicates it was use in the Physics 3 course at Harvard in the late 1920's.
Signedunsigned
Curatorial RemarksCard says the instrument was probably shop-built, but unclear whether this refers to the Jefferson Laboratory.
Inventory No. is 250a-e on original catalogue card, which probably refers to the following five items shown in the photo: two detachable coils, tripod base, suspension tube, and case.
FunctionThis reflecting galvanometer was used in the physics classroom 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, 1/8/1957.
American
Date: 1890-1930
Object number: 0155a,b,c,d
American
Date: 1890-1930
Accessories: extra set of coils without multi-tap windings (0156d, e); extra magnet; square wooden case
Object number: 0156a-f
Department of Physics, Harvard University
Date: 1890-1930
Accessories: extra set of coils without multi-tap windings (0156d, e); extra magnet; square wooden case
Object number: 0156a
Department of Physics, Harvard University
Date: 1890-1930
Accessories: extra set of coils without multi-tap windings (0156d, e); extra magnet; square wooden case
Object number: 0156b
American
Date: circa 1916
Accessories: extra binding posts (2)
Object number: 0141
Elliott Brothers
Date: circa 1930
Object number: 0232
