Gain-controlled electronic ballast circuit - has inverter transformer with taped prim. winding generating voltage across gas discharge tube in response to driving current

摘要

A filter circuit is connected to the power source to maintain a smooth d.c. voltage signal and suppress harmonic frequencies generated by the electronic ballast. Induction circuitry is coupled to the filter circuit and has a tapped prim. winding for generating a voltage across the gas discharge tube. The induction circuit has a number of sec. windings, one of which is a switching control winding for generating a switching signal. A switching circuit is coupled to the induction circuit for establishing the driving current at a practically constant and predetermined frequency responsive to the switching signal.