GB440196A - Improvements in and relating to electric discharge devices - Google Patents

Abstract

440,196. Cathode-ray tubes; amplifying circuits. BRITISH THOMSONHOUSTON CO., Ltd., Crown House, Aldwych, London. June 18, 1934, No. 18005. Convention date, June 21, 1933. [Classes 39 (i) and 40 (v)] Cathode-ray tubes comprise a cathode 5, a negatively biassed split cylinder 7 surrounding the cathode and projecting a flat beam of electrons through the slit 8; an accelerating electrode 9 with a slit 11 adjacent the slit 8 and two flat electrodes 12 parallel to the flat beam for deflecting it transversely and for maintaining its focus during its passage between the electrodes 12 to a beam receiving member such as a fluorescent screen or an anode 13. The electrodes 12 are maintained at a fixed average potential relatively to the cathode 5 to maintain the focus. As shown, control potentials are applied to the electrodes 12 across a resistance 24 and amplified potentials are taken from the two halves of the anode 13 joined by a resistance 27, the centres of the resistances 24, 27 being connected to tappings on the battery 20. Electrons passing between the two anode halves are received by a hollow anode 15 at a higher voltage. The tube may be used to amplify audio and radio frequencies and to detect radio signals. The electrodes are mounted on a multi-armed pinch and glass rods support them one from another. The envelope is highly evacuated using magnesium as a getter, or contains argon or neon.