reflecting galvanometer with moving magnet
Datecirca 1890
Inventory Number0198a,b
ClassificationReflecting Galvanometer
Subject
Maker
Gillis and Gleeson
User
Department of Physics, Harvard University
founded 1884
Cultural Region
Place of Origin
Dimensions43 x 18 x 18 cm (16 15/16 x 7 1/16 x 7 1/16 in.)
Material
DescriptionGalvanometer (0198b) with two pairs of coils in wooden frames. Coils encased in cylindrical wooden case with brass suspension tube (badly rusted) and mirror housing with circular viewing window. Two pairs of binding posts mounted on wooden case. Circular brass stand with tripod base (0198a) and three leveling screws.
Signedon top of case: GILLIS & GLEESON / BOSTON
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, 11/21/1956.
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
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
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