Thomson-Houston potential indicator
date: label: date made
content: 1889
name: label: maker
content: Thomson-Houston Electric Company
notes: label: Description (Brief)
content: This instrument is enclosed in a black wooden glass top case. Marked: "Potential Indicator / No. 2694 / Adjusted for 64 Volts / Patented Oct. 22. 1889 / Manufactured by / Thomson-Houston Electric Co. / Lynn, Mass. U.S.A." The indicator consists of a circular field core of many turns of relatively fine wire and a resistor across which is connected the voltage to be measured. A soft iron wire is pivoted eccentrically so as to be capable of rotation in the coil opening. The current produced tends to rotate the iron piece, which is controlled by gravity, to a position nearer the coil, causing a scale deflection as a measure of the applied voltage. The sensitivity of this form of voltmeter in ohms per volt was very low compared with that of the permanent magnet movable coil type just beginning to be available at that time.
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
creditLine: label: Credit Line
content: from Weston Electrical Instrument Corp., thru John H. Miller
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.313280
label: catalog number
content: 313280
label: accession number
content: 181342
objectType: label: Object Name
content: Voltmeter
label: Other Terms
content: Voltmeter; Measuring Devices
physicalDescription: label: Measurements
content: overall: 12 1/2 in x 10 in x 4 3/4 in; 31.75 cm x 25.4 cm x 12.065 cm