Patent ID: 6534929
Filing Date: 2003-03-18
Classification: H05B

Abstract:
An electromagnetic ballast for sequentially starting and simultaneously operating first and second gaseous discharge lamps, said ballast comprising:a. a transformer including a magnetic core, a primary winding for connection to an AC voltage source and first and second secondary windings, all wound around said core, said first and second secondary winding being wound in opposite directions to produce voltages in opposition to each other; b. a first series circuit including the primary winding, the first secondary winding, a first capacitor and the first lamp; c. a second series circuit electrically connected in parallel with the first secondary winding and including the second lamp, the second secondary winding and a second capacitor; said magnetic core having an elongated slot formed under the second secondary winding, said core and said slot having respective widths, substantially in a direction transverse to lines of flux produced in the core, such that a ratio of said slot width to said core width lies in the range of 60 to 70%.