reflecting galvanometer with suspended needle
Date1900-1920
Inventory Number0145
ClassificationGalvanometer
Subject
Maker
American
?
User
Department of Physics, Harvard University
founded 1884
Cultural Region
Place of Use
Dimensions31 × 11 × 11 cm (12 3/16 × 4 5/16 × 4 5/16 in.)
Material
DescriptionGalvanometer with small flat bar magnet (1/4") fastened to center of a mica air damping disk, hung on silk thread with mirror. Two multi-connection coils on each side of disk encased in cylindrical coil covers mounted on a rectangular nickel case with oval viewing window for mirror and nickel suspension tube. Eight small binding posts on one coil cover and two large binding posts on other coil cover with two grounding terminals on front of case. Tripod base with three leveling screws. Similar to object 0144a,b.
Signedunsigned
FunctionThis galvanometer measures small current displacements with a compass needle attached to a small mirror and magnet suspended on a silk thread from the top of a suspension tube. When the needle and mirror are mounted between the two coils and an electric current is passed through the coils, it induces a magnetic field that causes the coils to rotate in proportion to the current deflections, twisting the suspended magnet and mirror. The current deflections can then be detected using a light beam that reflects off the mirror and onto a scale.
ProvenanceFrom the Department of Physics, Harvard University, 11/20/1956.
Department of Physics, Harvard University
Date: 1900-1920
Object number: 0144a,b
American
Date: circa 1916
Accessories: extra binding posts (2)
Object number: 0141
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: 1890-1930
Object number: 0155a,b,c,d