GB233697A - Improvements in and relating to amplifying tubes for wireless telephony - Google Patents

Abstract

233,697. Schweiz Gl³hlampenfabrik Akt.-Ges., and Burk, K. May 7, 1924, [Convention date]. Vacuum tubes. - In thermionic tubes for wireless telephony of the kind comprising a disc anode a with an aperture at its centre through which the grid and cathode extend transversely to the disc, the grid comprises, instead of a helix, a double cone c with the smallest diameter lying in the plane of the disc a from which the two cones increase in diameter on both sides of the anode. The cones extend in opposite directions for equal distances at right-angles to the disc a and may comprise two wires e<1>, e<2> partly twisted together, the lower end of the twisted part being secured to a suppoirting lead f and the wires being formed individually into spirals from the top end of the twisted part with the free ends unsupported. The anode may be strengthened by corrugations and is supported on a single lead d, the leads d, f and the leads from the heated filament b being mounted in the glass h. In removing traces of gas from the anode during evacuation of the bulb, the disc a may be exposed on both sides to electronic bombardment; whilst, when the tube is amplifying, capacity between grid and anode tending to produce self -oscillation is small and electron control by the grid is improved.