GB487044A - Improvements in frequency-changing arrangements and electric discharge tubes for use therein - Google Patents

Abstract

487,044. Electron oscillators. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN. Feb.9, 1938, No. 4067. Convention date, Feb. 12, 1937. [Class 39 (i)] In a frequency-changing device comprising a pentagrid tube, one or more secondary electron emitting surfaces are arranged in the neighbourhood of the anode of the oscillator section and are so disposed as to prevent material which vaporizes from the cathode reaching them, the electrons proceeding from the cathode being caused to impact thereon by means which cause them to travel in curved paths. As shown in Fig. 1, the secondary electron emitting surfaces 5 are preferably carried by the screening electrode 4 which consists entirely of a grid and surrounds the cathode 1, control grid 2 and the rod shaped anodes of the local oscillator. The surfaces 5 are in the shadow of the rods 3 supporting the grid 2, and electrostatic or electromagnetic deflecting means may be provided for causing the electrons from the cathode to take the curved path necessary to reach the surfaces 5. In Fig. 2, the secondary electron emitting surfaces are formed on the parts 6 of a screening grid formed partly of solid material and enclosing the oscillator anodes. The parts 6 are shadowed by the supports 3 of the control grid 2. The other electrodes comprise an input control grid 9, screen grid 10, and anode 11 with or without a suppressor grid 12 between the two last.