reflecting galvanometer with moving magnet
Date1890-1930
Inventory Number0156a-f
ClassificationReflecting Galvanometer
Subject
Maker
American
?
User
Department of Physics, Harvard University
founded 1884
Cultural Region
Place of Use
Dimensions42.1 × 20.3 × 18.2 cm (16 9/16 × 8 × 7 3/16 in.)
Material
Accessoriesextra set of coils without multi-tap windings (0156d, e); extra magnet; square wooden case
DescriptionGalvanometer with one pair of permanent coils having multi-tap windings. Pair of magnets suspended on a thread with a mirror from two brass rod suspension tubes. Coil encased in square wooden case mounted on cylindrical tripod base with three leveling screws. Blackened brass cylindrical case with suspension tube (0156c) fits over wooden case and has three windows with arrangement for holding mirror in front of one window. Two binding posts on platform extending from base. Bar magnet hung on rod below case. Similar to object 0155a-d.
Painted blue triangle indicates use in Physics 3 course at Harvard in the late 1920s.
Painted blue triangle indicates use in Physics 3 course at Harvard in the late 1920s.
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.
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
American
Date: 1890-1930
Object number: 0155a,b,c,d
Department of Physics, Harvard University
Date: 1900-1920
Object number: 0144a,b
