GB405499A - Improvements in and relating to gaseous electric discharge apparatus - Google Patents

Abstract

405,499. Discharge apparatus. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Kenty, C. E. ; 650, Palisade Avenue, Jersey City, New Jersey, U.S.A.) May 9, 1933, No. 13483. Convention date, May 9, 1932. Addition to 395,851. [Class 39 (i).] A tube having a filling consisting of a main gas and a trace of another gas of which the ionizing potential is substantially the same, or somewhat less than a metastable potential of the main gas is started by discharges adjacent each main electrode and between each of these electrodes and an adjacent auxiliary electrode within the tube, which discharges are created by potentials equal to or less than the main supply voltage. In one form Fig. 1, a lamp having a filling of neon plus 0.2 per cent oxygen at a pressure of 1 to 3 m.m. has an indirectly-heated electrode 2 surrounded by a shield 6 at each end, and two auxiliary anodes 9, 10 are excited from tappings on an autotransformer 12 connected across the alternating-current mains to which the electrodes 2 are connected through a ballast resistance 11. The lamp may be U-shaped. In a modification an M -shaped tube has three main electrodes with a pair of auxiliary anodes adjacent each. One electrode is arranged at the mid-point of the tube and is connected to the mid-point of the autotransformer. A continuous-current lamp has a heated cathode and auxiliary electrodes near both anode and cathodes each connected to the other main electrode through a resistance. In another modification, a ring-shaped auxiliary anode is mounted near each main electrode and is fed with continuous-current from a full-wave rectifier supplied by the transformer.