classroom demonstration galvanometer
Date1850-1875
Inventory Number0446
ClassificationGalvanometer
Subject
Maker
Heinrich Daniel Ruhmkorff
1803 - 1877
User
Department of Physics, Harvard University
founded 1884
Cultural Region
Place of Origin
Place of Use
Dimensions42.2 × 41.9 × 25.1 cm (16 5/8 × 16 1/2 × 9 7/8 in.)
Material
DescriptionA demonstration astatic galvanometer with one needle within the coils, one above on same shaft, mounted vertically with pointer and scale and contained in large removable wooden case with glass cover. There are four leveling screws and four binding posts on the wooden base. One of the binding posts has been dislodged. The dial for registering the deflection of the needle is marked every five degrees with large numbers 40-0-40.
Signedmarked on scale: Ruhmkorff à Paris
Curatorial Remarks(Description from original card): "Astatic galvanometer movement -- one needle within the coils, one above on same shaft, mounted vertically with pointer 2 scale 17' long contained in large demountable care with glass cover. Large numbers 40-0-40 on scale."
FunctionSuch an instrument is used to measure electric currents. A compass needle is pivoted in the middle of a coil. Passing a current through the coil exerts a torque on the needle, which then aligns itself with the resulting magnetic field.
ProvenanceFrom the Department of Physics, Mallinckrodt Laboratory, Harvard University, 1954.
Heinrich Daniel Ruhmkorff
Date: circa 1859
Object number: 0193a,b
Heinrich Daniel Ruhmkorff
Date: 1850-1870
Object number: DW0852
Heinrich Daniel Ruhmkorff
Date: 1860-1880
Accessories: instrument parts of various shapes and sizes (b)
Object number: 1997-1-0255a
Heinrich Daniel Ruhmkorff
Date: 1860-1875
Object number: 1996-1-0531
