METAL VAPOR DISCHARGE LAMP

摘要

PURPOSE:To prevent the damage of an electrode and a luminous tube from becoming sooty and to make the start rapid and sure by connecting an auxiliary electrode provided near a main electrode to an opposing main electrode side through a negative resistance element and constantly closed thermally operating switch. CONSTITUTION:A luminous tube 4 is contained in an outer tube 1, and main electrodes 7, 8 are provided on the both ends of the luminous tube 4. An auxiliary electrode 9 is provided near the main electrode 7. The main electrode 7 is connected to a lead wire 10 sealed in a stem 2 through a support 5, and the main electrode 8 is connected to a lead wire 12 through a lead wire 11. The auxiliary electrode 9 is connected to the lead wire 12 through a negative resistance element 13 and constantly closed thermally operating switch 14.