Abstract: The invention provides a filament cutout circuit for a fluorescent lamp (60). The filament cutout circuit includes a filament transformer (20) with a primary winding (22) and at least one secondary winding (24, 26, 28), and a cutout transistor (30) serially connected to the primary winding (22). The secondary winding (24, 26, 28) provides a filament voltage to a filament (62, 64) in the fluorescent lamp (60). A filament control input (12) turns on the cutout transistor (30) for a predetermined time period to preheat the filament (62, 64).

Abstract: The invention provides an electronic ballast for a fluorescent-lamp (20), including a fluorescent-lamp ballast circuit (30), an arc detection circuit (40) electrically connected to the fluorescent-lamp ballast circuit (30), and a lamp cutoff device (50) in series with the fluorescent (20) and electrically coupled to the arc detection circuit (40). The fluorescent-lamp ballast circuit (30) provides power to the fluorescent lamp (20). The lamp cutoff device (50) is opened when arcing is detected by the arc detection circuit (40).