Electronic ballast system for discharge lamp circuit - restricts and stabilises current and applies rectified input to oscillator providing high frequency to lamp for high efficiency operation

摘要

The ballast connects to the mains supply via the full wave rectifier (R), the filter (F) and the mains current modifier (M). Between the resulting DC terminals and the lamp (8) a high frequency oscillator is comprised of two series connected transistors (1,2) with diodes (12,13) in series with the emitters of the transistors. One terminal of the primary winding (4) of the base drive transformer (3) is connected between the transistors whilst the other terminal connects to a lamp electrode via the choke (7). The other lamp electrode connects via resonance capacitors (10, 11) and voltage limiter diodes (23,24) to opposite poles of the 05 supply.