GB413302A - Improvements in electric discharge devices and circuits used therewith - Google Patents

Abstract

413,302. Discharge apparatus. DEHN, F. B., 103, Kingsway, London.- (Radio Research Laboratories, Inc. ; 597, Madison Avenue, New York, U.S.A.) Jan. 9, 1933, No. 756. [Classes 39 (i) and 40 (v).] A discharge tube for use as a detector, amplifier, or frequency doubler contains an ionizable medium and has a cold cathode, a cathanode, a control electrode, and an anode, the cathode or anode being of rod or cylindrical shape and surrounded by a concentric cylindrical electrode, closed at its upper end by an insulator and at its lower end by an insulator contiguous or integral with the press. As shown in Fig. 1 the cathode consists of a rod 3 surrounded at the ends by glass beads 4, 4A, which support a cathanode 5 in the form of a helix, mesh or perforated cylinder. A control grid 6 and an anode 7 are supported by the press and are spaced by an insulating cross-bar 8. Dimensions of the spacing of the electrodes 3, 5 are given. The cathanode is connected with a tapping on a resistance across the anode battery, so that at starting the full battery potential is applied between the electrodes 3, 5. A high resistance in the cathode circuit limits the current after ionization has started. The tube shown in Fig. 5, has an internal anode 33 spaced at the ends by insulating beads 34, 34<A> from a control electrode 35, the cathanode 37 being spaced from the electrode 35 by an insulating bead 36. A band 38 secures the assembly. The cathode 40 consists of a ring or semi-circular member of carbon silicon, boron or aluminium ; or the cathode may be a point, a short-rod, or an aluminium pin secured at a distance from the other electrodes in a block of carbon. The filling may be dry air, or neon at a pressure of 1 to 50 millimeters or more, or nitrogen at 12 millimeters. A circuit providing regeneration is shown in Fig. 9. The input circuit IP is connected between the control electrode 35 and the cathanode 37, and the output O.P. between the anode 33 and cathode 40, the ionized gas forming a low impedance between he anode and controlelectrode. In a modified circuit, Fig. 10 not shown, the electrode 35 is connected through a condenser to the positive side of the battery or to earth and the electrode 37 acts as control electrode ; the amount of regeneration, which may be reduced to zero, depends on the size of the condenser. Characteristic curves are given. Specification 413,303 is referred to.