FLUORESCENT LAMP BALLAST WITH ELECTRONIC PREHEAT CIRCUIT

摘要

Fluorescent lamp ballasts and methods are disclosed in which a resonant impedance of a self- oscillating inverter is modified to control the inverter frequency to selectively preheat lamp cathodes using power from the inverter output during a preheating period after power is applied and to change the inverter frequency to a different range following ignition of the lamp.