Lighting unit having power supply with improved switching means
 An energy efficient lighting unit is described designed for functional similarity to the incandescent light used in the home. The lighting unit utilizes a metal vapor arc lamp as the main source of light supplemented by a standby filamentary light source. The lighting unit includes means for converting 60 hertz ac to dc, and a dc energized operating network containing a three transistor switch. The transistor switch is used to provide dc and low frequency (120 Hz) energization to the filament, and high frequency energization for both filament and arc lamp. The high frequency energization, which starts and transitions the arc lamp, is discontinued after the arc lamp is started. In the final run state, the arc lamp, which is serially connected with the filament across the dc supply, is ballasted by the filament. The transistor switch is controlled in its operation by an integrated circuit. 
General Electric Company
H
H05B
inventional
Thomas A. James E. Marc A. William
Brown Harris Dissosway Peil