GB568810A - Improvements relating to electric discharge lamps - Google Patents

Abstract

568,810. Supply systems for discharge lamps. SIEMENS ELECTRIC LAMPS & SUPPLIES. Ltd., and ALDINGTON, J, N. Aug. 21, 1943, No. 13665. [Class 38 (iv)] [Also in Croup XL] A discharge lamp L for giving intermittent flashes is energized by a source of current MS of a voltage lower than the starting voltage and a condenser K in parallel with the lamp. Starting electrodes SE are provided internally of the lamp at a distance less than half the electrode spacing, and are energized by a source SS in circuit with an operating switch SSW. One of the starting electrodes may be the main electrode as in Fig. 2 (not shown). which also shows the starting discharge as derived from a. transformer energized from the main supply. The operating voltage of the discharge is derived from the secondary of a transformer MTR and a thermionic rectifier R. As shown, the lamp comprises a tubular portion with spherical end chambers for the electrodes A, C, but it may be of other shapes such as helical or grid-like. It has a filling of mercury with or without inert or rare gases such as neon or argon, and the electrodes may be of tungsten or a mixture thereof with thoria. The envelope may be of a high-melting point glass or quartz. and in the latter case may have an exterior coating of fluorescent material. With a gas pressure of 30 mm. of mercury, the spacing of the starting electrode may be 1 to 2 mm.