a ballast circuit for a fluorescent lamp including a rectifier - filter for coupling to an ac power supply to generate a dc voltage , an oscillator circuit coupled to said dc voltage for developing an rf oscillator signal , and switching signal means for developing concurrent oppositely phased switching signals at the frequency of said oscillator signal to drive series connected power transistors . the common output of the power transistors is coupled to energize a fluorescent lamp coil and regenerative feedback means for generating a signal to aid in switching the power transistors .