A starting circuit for an electric discharge lamp providing an electric current to a lamp having a first and a second filament. The circuit measures a lamp current and a filament temperature and then compares these against a reference voltage. When the lamp current is below a set threshold value, a relay contact disposed between the first and second filament is closed to direct the electric current through the first and second filaments to initiate pre-heating of the lamp. Once the filament temperature exceeds a set threshold, the relay contact is opened and the electric current passes through heated gas inside the lamp.

 
Web www.patentalert.com

< Apparatus and method for removing mercury vapor from a gas stream

> Indirectly heated electrode for gas discharge tube, gas discharge tube using said indirectly heated electrode, and lighting device for said gas discharge tube

~ 00446