| 摘要 |
PURPOSE:To reduce a noise by connecting a condenser in parallel to the primary winding of a preheating transformer. CONSTITUTION:By the LC series resonance of a choke coil 8 and a condenser 7, discharge lamps 4 and 5 are started to preheat, a current flows in the primary winding 6a of a preheating transformer 6 through the condenser 7, and by the voltage induced in the secondary winding 6b, a circulation current flows in the filaments 4b and 5a of the discharge lamps 4 and 5 respectively to preheat the filaments 4b and 5a, and the discharge lamps 4 and 5 are lighted all at once. To the winding 6a, a noise preventive condenser 9 is connected in parallel, the transformer 6 is made into the earthing potential of a lighting device through the condenser 7, the filaments 4b and 5a never get a high-frequency potential, and the generation of noise can be reduced. |
