GB683611A - Improvements in or relating to electric discharge tubes and circuit arrangements therefor - Google Patents

Abstract

683,611. Discharge apparatus. STANDARD TELEPHONES & CABLES, Ltd. Nov. 19, 1948, No. 30087/48. Class 39(i) [Also in Group XL(c)] The trigger electrode of a cold cathode triggered anode gasfilled glow discharge tube surrounds the anode so as to screen the same from the electric field of the cathode in the absence of discharge between the trigger and anode electrode, thus enabling the tube to be connected in a circuit arrangement (see Group XL(c) ) wherein the supply voltage is greater than the anode-cathode breakdown potential. The tube shown comprises a glass envelope 1 having presses 2 and 3 at either end. The trigger electrode 8 is in the shape of a truncated cone surrounding the anode 7 and has a cylindrical portion 12 with projecting flanges 13 and 14 welded to support rods 9 and 10, located by a mica spacer 11. The cathode 4, which may have an activated coating, is mounted on leads 5 located by a mica spacer 6, and is concavely shaped to concentrate the discharge therefrom within the trigger cone. The tube is suitable for direct connection in the wiring of a circuit without using a valve socket. In a modified form, adapted for use with a conventional valve socket, the anode, cathode and trigger electrode are all mounted on one press, and the envelope is fitted with an ordinary valve base. Typical characteristics and dimensions are given.