Weston Potential Indicator

In the 1880s—the early days of commercial electric power—convenient, rugged, and reliable instruments for measuring that power did not exist. Engineers had to struggle with complex, delicate, laboratory-type instruments that required leveling, calibration, and manipulation to yield a reading, which then required calculation to yield a meaningful number. Edward Weston, an immigrant English entrepreneur and electrical inventor and engineer, developed this instrument for measuring direct current potential, patented in 1886, to answer the demand for a better way. Although its leveling screws, delicate suspension, and glass shade (now missing) betray its laboratory antecedents, the hefty magnet, the moving coil design, and the "direct reading" pointer and scale show the direction in which Weston was heading. His subsequent instruments soon secured a worldwide reputation for reliability, precision, and ease of use.
Currently not on view
Object Name
Date made
about 1888
Weston, Edward
Physical Description
brass (overall material)
wood (overall material)
overall: 11 in x 11 1/4 in; 27.94 cm x 28.575 cm
ID Number
accession number
catalog number
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Work and Industry: Electricity
Energy & Power
Data Source
National Museum of American History, Kenneth E. Behring Center


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