Galvanometers
Fine selection of various static, astatic, and tangent galvanometers.
Astatic Galvanometers are precision instruments used to detect small electric currents by generating a magnetic field. Thereby changing the direction of a suspended compass needle. From measuring the deflection of the compass needle from true North, the electric current can be detected, as well as it's relative strength (if needle moves completely around, the charge is greater- if the needle barely moves, the charge is smaller). As telescopes first showed us the macro world, astatic galvanometers first showed us the micro world. This instrument was a first for sensitive and quantitative electrical data, paving way for the incredible advancements in electron studies and technological innovations ever since.
Tangent Galvanometer's built on this concept and were designed to deflect the compass needle when electrical currents are passed through the vertical copper coils.
Tangent Galvanometer by W.B. Nicolson
Antique Tangent Galvanometer. Irish made, circa 1945. Signed 'W.B. Nicolson, Scientific Instrument Maker, Glasgow'. Composed of wood, brass, and glass. 9 turns on front (three knobs), 50 turns on back (two knobs). Displayed in glass cloche. Mirrored dial is numbered 0-90-0-90, original steeled needle. Base sits atop three adjustable brass legs.
Similar Model Featured in The Science Museum Group.
Astatic Galvanometer by A.P. Gage
American made, circa 1880-1900. Astatic Galvanometer , signed 'A.P. Gage, Boston'. Original paper face is numbered 0-90-0-90, and reads: 'The Astatic Needle is used only when the Galvanometer is required to be very sensitive. Resistance 0.43 ohm.'
Galvanometer sits atop a Mahogany base, on thre adjustable brass legs. Displayed in antique glass cloche.
Featured at the Hampden-Sydney College.
Telegraph Works Galvanometer
Signed 'Teleworks, Silvertown London, No. 2752. For single current type ( 22ohms) with 2 brass terminals, 4 quadrant scale 0-90, and compass type pointer. It would have been used by engineers testing lines for the Post Office in conjunction with a Wheatstone Bridge. British made, circa 1920.
Unserialed Model Featured in the Powerhouse Collection.
Astatic Galvanometer by Central Scientific Co.
Astatic Galvanometer, late 19th century. Made by Central Scientific Company. Good condition. Galvanometer with magnetized needle above and in fixed coils. An aluminum pointer attached to needles is suspended by a thread above paper scale graduated from 0°-90°-0°-90°-0°. L-shaped brass suspension support. Coils rest on circular brass base, with two binding posts and three leveling screws. A bell jar enclosure covers the meter.
Dollar Tangent Galvanometer
English or American made, circa 1920-1940.
Similar Model Featured in the Science Museum Group.
Unsigned Single Current Galvanometer
Unsigned Galvanometer. Made of Walnut and lacquered brass. Marked 90-0-90. Half-blue steeled needle, with Ruby pivot. Original glass.
Taylor Haus Galleries
Unipivot Galvanometer by Cambridge Instrument Co. Ltd.
