| 摘要 |
PURPOSE:To enhance starting characteristics without impairing the lighting state maintaining performance by connecting a capacitor in parallel to a zenor diode, and interposing a diode, for prevention of discharge which is to be in series connection with a three-terminal thyristor, between a bias resistance and voltage dividing resistances. CONSTITUTION:A capacitor C is connected in parallel to a zenor diode 2D inserted in the gate of a three-dimensional thyristor SCR. Between a bias resistor R3 and voltage dividing resistances R1, R2, is interposed, a diode D for prevention of discharge which is to be in series connection to the three-terminal thyristor SCR. Thereby the judgement value of lamp voltage can be decreased at preheating to enhance the starting characteristics, and the same value is set higher at the time of lighting up without impairing the lighting state maintaining performance. |
