On this day in 1897 Elihu Thomson was granted the patent for ELECTRIC MEASURING INSTRUMENT. U.S. Patent No. 590,654.
This invention relates to voltmeters and involves in its construction a fixed coil located at an angle and a movable coil located within the fixed coil at an angle thereto, such arrangement being set forth in United States Letters Patent No. 554,321, granted February 11, 1896. In the invention set forth in said Letters Patent the movable coil is connected in shunt with the fixed coil, so that the instrument forms a watt-indicator.
In the present invention the two coils are in series with each other and with a resistance, and the instrument is designed for a voltmeter.
