GB758455A - Improvements in or relating to electric circuits for discharge lamps - Google Patents

Abstract

758,455. Supply and switching systems for space-discharge lamps. BOIN, R., and BOIN (nee DOMS), G. Sept. 10, 1953 [Sept. 10, 1952], No. 25114/53. Class 38 (4). An electrical circuit for use with an A.C. supply of predetermined frequency comprises a discharge lamp L having two preheatable cathodes 1, 2 directly mutually interconnected electrically in series by the secondary coil S of a transformer, and a condenser C, the transformer primary coil P, the condenser C, and the parallel combination of the lamp L and secondary coil S all being serially connected across the supply and the inductance and capacitance of the circuit being such that the circuit is substantially in resonance when the lamp is non- conductive. The primary and secondary coils may be loosely magnetically coupled by the interposition of one or two magnetic shunts F, the primary coil may be divided into two parts P, PI, and the condenser and primary coil parts may be elsewhere in the circuit but not in the lamp/secondary coil combination. There may be a further lamp serially connected with lamp L and supplied by a further secondary coil connected directly across it, or the coil S may have coupled to it cathode heating secondary windings which supply the cathodes of a further lamp which, in series with a saturable inductance, is shunted across the entire circuit. A supply and switching control circuit for one or more groups of three lamps is also described.