Patents Assigned to E. W. Controls Limited
  • Electric lighting systems
    Patent number: 4004185
    Abstract: A method and apparatus of lighting a cold cathode electric gas discharge lamp in which the lamp is connected across the secondary winding of a voltage step-up transformer, and the primary winding of the transformer is energized with a chopped D.C. voltage having a frequency of at least 12 kHz and a voltage which provides an output voltage from the secondary winding having an R.M.S. value no greater than 700 volts.
    Type: Grant
    Filed: April 25, 1975
    Date of Patent: January 18, 1977
    Assignee: E. W. Controls Limited
    Inventors: Harry Edmondson, Walter Whittaker