GB646894A - Improvements in electric discharge tubes - Google Patents

Abstract

646,894. Electric discharge lamps. MAPLE & CO., Ltd., HISCOCK, E., and WILLIAMS, H. June 30, 1948, No. 17545. [Class 39 (i)] A gas-filled electric discharge tube D (Fig. 1), is provided with one or more starting strips, each connected to one of the electrodes E1, E2 and insulated from the positive column, comprising a conducting rod, a film of graphite, or as shown, a helix of wire H, preferably enclosed in a sealed glass tube G, supported by the electrodes. External conducting strips (not shown) may also be applied to the external surface of the tube. The tube electrodes E1, E2 may be hot or cold, and the filling may be any suitable gas or vapour, while the tubes G may be coated with fluorescent material. Bridge-pieces L of conducting material may be assembled across the positive column, and mechanically attached to the glass tubes G as described in Specifications 522,510 and 617,832, to provide indicia. In another embodiment (Fig. 5), the tube is equipped with a bayonetcap fitting O, and the upper helix H is connected in series with the lead to electrode E1, to act as an internal ballast resistance. Specifications 405,514 and 523,839 also are referred to.