Hot Wire Voltometer 1890

  • The instrument makes measurements of voltage equally well on both AC and DC supplies.
  • Its accuracy is independent of ambient temperature.
  • This type of voltmeter was invented by Major Cardew in 1883.
  • He was the first electrical adviser to the Board of Trade and devised the first set of Electricity Regulations.
  • He established the Board of Trade electrical standards laboratory for the calibration of electricity meters.
  • This instrument was formerly used at Burghill Hospital in Hereford.