reflecting galvanometer with moving magnet
Datecirca 1915
Inventory Number0153a-d
ClassificationReflecting Galvanometer
Subject
Maker
American
?
User
Department of Physics, Harvard University
founded 1884
Cultural Region
Place of Use
Dimensions49.5 × 21.5 × 21 cm (19 1/2 × 8 7/16 × 8 1/4 in.)
Material
DescriptionGalvanometer with two pairs of permanent coils (one above the other) with watch spring magnets suspended at coil centers on aluminum wire and with mirror in between the magnets on the suspension. Coils (0153c) encased in rectangular wooden case with quartz suspension thread supported on three brass rods. Wooden case mounted on cylindrical base. Blackened brass cylindrical case (0153b) with suspension tube (0153a) and oval viewing window fits over wooden case and bar magnet hung on rod below case. Tripod base (0153d) with three leveling screws. Eight small binding posts on bakelite platform extending from base. Similar to object 0154a-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: 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
American
Date: 1890-1930
Object number: 0155a,b,c,d
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
Elliott Brothers
Date: circa 1930
Object number: 0232
