DC ammeter

Datecirca 1905

Inventory Number1997-1-0330

ClassificationAmmeter

Subject

Maker Weston Electrical Instrument Corporation founded 1888

Cultural Region

Place of Origin

Dimensions22.1 × 20 × 12.1 cm (8 11/16 × 7 7/8 × 4 3/4 in.)

Material

DescriptionA wooden box with a hinged lid that allows access to its top half. Inside one finds a metal box with an arc-shaped window, the contours of which are outlined by a metal frame that also forms a semicircle on the exposed part of the instrument (probably a full circle). The frame seems to be decorative.

The scale of the instrument is linear and has two different sets of values: one in black above it, going from 0 to 30; the other below it in red, going from 0 to 15. A very thin needle moves over it, and there is a reflecting band below the scale.

There are two electrical connectors, at the top left and top right corners of the metal box, and the one on the right is labeled + by a metal knob on the edge of the wooden box nearby.

The box has a leather strap on its top side.

Signedplaque on inner surface of lid: MADE BY THE / WESTON ELECTRICAL INSTRUMENT Co / NEWARK, N.J., U.S.A. / PATENTED / NOV 8, 1888, FEB. 17, 1891, MAY 14, 1889, DEC 19, 1893, JUL 16, 1901, APR 29, 1890, OCT 4, 1891 / MODEL 45 No. 12357 below scale: WESTON D.C. AMMETER MODEL 45

Inscribedover scale: USE ONLY WITH EXTERNAL SHUNT

FunctionAn ammeter for direct current. It is most likely a galvanometer. Seems to be designed for portability.