Watt Electrical Instrument Co. Ltd. A.C. Voltmeter, Bradford, England. A portable analogue voltmeter designed for measuring alternating current voltage in electrical distribution systems and laboratory testing. The instrument uses a moving-iron movement with a clear scale from 0–300 volts and is mounted in a protective wooden carrying case with top terminals for connection. Commonly used by electricians, power engineers, and maintenance technicians for testing mains supplies and equipment. Mid-20th century, dated 1947.
