GB754169A - Cathode ray tube circuit arrangement - Google Patents

Abstract

754,169. Cathode-ray tubes. RADIO CORPORATION OF AMERICA..June 16, 1954 [July 10, 1953], No. 17724/54. Class 39 (1). [Also in Group XL (c)] Vibration of a grid adjacent the screen of a colour television tube due to voltage fluctuations induced on the grid and on an adjacent electrode at a different voltage, by load variations of the sources of voltage, is eliminated by making the voltage fluctuations of the electrodes equal or nearly so. Voltage fluctuations may be coupled from one electrode to the other, e.g. through a condenser, or suitable voltage fluctuations may be induced on one electrode by adjusting the regulation of the voltage source. The grid 24, Fig. 6, and screen 16 of a three-gun post deflection deceleration tube are connected to a 15 kv. voltage source and the grid 26 to a 20 kv. source. The 15 kv. source includes a voltage regulator tube 54. The voltage fluctuations of the 15 kv. source are increased to equal those of the 20 kv. source by reducing the efficiency of regulation. The filter 48, 49, 50 attenuates voltage fluctuations transmitted from the tap 47 of the voltage divider 52 to the grid of the tube 54. Voltage fluctuations may be fed from the 20 kv. source to the cathode of tube 54 through voltage divider 51 and filter 56. Voltage variations in the load current may be fed to the 15 kv. grid 24. The television tube may be of the post deflection acceleration type with a single grid associated with the screen 16, or of the type with a single gun and beam switching grids 104, 106, Fig. 11, in front of the screen 100. The grids are connected to a 5 kv. source 108 through impedances 114, 116 relatively high to the high-frequency switching voltages, but relatively low to voltage fluctuations due to load changes. The voltage fluctuations of the 20 kv source 102 for the screen 100 are coupled to the grids through a condenser 118.