GB480521A - Improvements in or relating to cathode ray television apparatus - Google Patents

Abstract

480,521. Supply systems for cathoderay tubes.RADIOAKT.-GES. D. S. LOEWE. May 22, 1936, No. 14514. Convention date, May 22, 1935. [Class 38 (iv)] [Also in Group XL] Switching control.-In television image reconstructing means for use with different numbers of scanning lines, a cathode ray tube is employed in which the image point is produced by an electron lens as the image of the aperture in a diaphragm 1, and the size of the image point is regulated by the variation of the potential of the diaphragm, while the energy of the ray is simultaneously readjusted to a desired value by variation of the potential of one of the anodes 4 of the tube so as to maintain constant the intensity of the picture. A switching arrangement is shown which performs the two variations simultaneously and also adjusts the amplitude of the deflecting potentials. The voltage for the anode 4 and that for the associated lens electrode 3, tapped from the potential divider 9, is supplied by a voltage-doubling rectifier to the load resistance 17, which has tappings a, b, c connected to the electrode 1 through studs on a double pole, three position switch S, the other poles of which are connected to tappings on the primary of transformer 10, the arrangement being such that as the voltage supplied to the rectifier is reduced, the diaphragm 1 is tapped up on the resistance 17. The voltage supply to the scanning oscillators 16 is taken from one of the reservoir condensers 14 ; consequently as the voltage on the anode rises and increases the electron velocity, the amplitude of the scanning voltage is correspondingly increased. Specifications 455,797, [Group XL], 466,770, and 468,891 are referred to.