Abstract: A half-bridge inverter is powered from an ordinary electric utility power line by way of a full wave rectifier-filter means. The high frequency voltage output of the inverter is loaded with a series-combination of a tank inductor and a tank capacitor, with a fluorescent lamp being connected in parallel with the tank capacitor. The ON-time of each of the inverter's two transistors is shorter than half the period of the high frequency voltage; thereby preventing the two transistors from conducting simultaneously; thereby, in turn, protecting the inverter from self-destruction in case of lamp failure.

Abstract: A ballast enclosure made of metal and including a rectangular enclosure body having mounting bosses integrally formed in the side walls thereof. Preferably, the bosses are formed by stamping the bosses into the sidewalls and are so constructed and arranged that they can receive self-tapping screws to attach the enclosure to an adjoining wall. Mounting flanges are also provided.