GB265204A - Improvements in or relating to discharge tubes having an enclosed arc discharge - Google Patents

Abstract

265,204. Naamlooze Vennootschap Philips' Gloeilampenfabrieken. Jan. 29,1926, [Convention date]. Arc lamps; arc-lamp electrodes. -In electric discharge tubes with an enclosed arc discharge in a rare gas, one or more fixed auxiliary electrodes 3 are provided between the main electrodes 1, 2, the electrodes 3 being annular, rectangular or of other form allowing the discharge to pass and having, during the discharge, a negative potential with respect to the negative electrode. The electrode 3 attracts positive ions which are moving towards the anode and which tend to neutralize the space charge at the anode, the voltage drop and thus the heating of the anode at a given current being increased. The ring 3 between spherical tungsten electrodes 1, 2 may be kept at negative potential by an external lead; for example, the ring 3 and the cathode 2 may be connected respectiveJy directly and through a resistance 5 to the negative pole of a direct-current source supplying the arc. In a modification, the ring 3 may be insulated and without an external lead, being maintained negative by electrons during the direct or alternating-current discharge. Specifications 181,675 and 188,627 are referred to.