| 摘要 |
PURPOSE:To diminish the dispersion of the surge voltage of a metal vapor discharge lamp and improve the life of a luminous tube, by enclosing mercury or 10<-4>-10 Torr gas in an outer tube and arranging between the bimetal and the current-limiting resistance an electrode, to be connected so as to equalize its potential to that of a current-limiting resistance when a bimetal is open. CONSTITUTION:A starting circuit 5 is built up by connecting in series a current- limiting resistance 6, namely a tungsten coil fixed by winding on a resistor fixing frame 7, a heat responsive switch built up with a bimetal piece 9, contacts 10, 11 and the like. A electrode 31, made of a tungsten stick containing sodium oxide and having a sharpened tip, is located between contacts 10, 11 and the current-limiting resistance 6, and connected with a frame snap 15, and, putting its tip toward the contact points of contacts 10, 11, fixed at a position, for example, 4mm. distant from the contact points. Thereby, the dispersion of a surge voltage can be diminished, and the life of a luminous tube can be improved. |
