reflecting galvanometer with moving coil
Date1890-1920
Inventory Number0157a,b,c
ClassificationReflecting Galvanometer
Subject
Maker
American
?
User
Department of Physics, Harvard University
founded 1884
Cultural Region
Place of Use
Dimensions58 × 18 × 18 cm (22 13/16 × 7 1/16 × 7 1/16 in.)
Material
DescriptionAyrton and Mather type galvanometer with coil (0157c) suspended between pair of painted black D-shaped magnets raised on three rods attached to a round wooden and metal tripod base with three leveling screws. Double brass rod suspension tube (0157a) supports mirror above coil. Blackened brass cylindrical case (0157b) with three viewing windows in the suspension tube. Similar to object 0158a,b,c.
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 scale placed in front of the meter.
ProvenanceFrom the Department of Physics, Harvard University, 11/6/1956.
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 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
Leeds & Northrup Company
Date: circa 1920
Object number: 0551