GB254731A - Improvements in electron discharge apparatus - Google Patents

Abstract

254,731. British Thomson-Houston Co., Ltd., (Assignees of Warner, J. C.). July 1, 1925, [Convention date]. Vacuum tubes.-A valve having a cathode 2, an anode 3, a control grid 4, and a space-charge grid 5, is provided with means, such as a third grid 6, for increasing the impedance of the electron path between the cathode and the spacecharge grid. The energy supplied to the output circuit from the space-charge grid is thereby greatly increased without decreasing the effect of the control grid on the space-charge grid current. The grid 6 is maintained by means of a tapping 12 at a potential lower than that corresponding with the potential gradient at the point at which the grid is mounted. The control grid 4 is mounted adjacent to the anode, and is connected with the input transformer 7. The anode is connected through a part of the primary winding 9 of the output transformer with the high potential source 8, and the space-charge grid 5 is connected to the other part of the primary winding through a resistance 10. As the current variations produced in the circuits of the anode and space-charge grid are opposed, the currents in both parts of the primary combine in their effects upon the secondary 11. The potential of the space-charge grid may be adjusted so that the continuous current fields of the two parts of the winding 9 balance each other. In a modification the output from the space charge grid is used to vary the voltage drop across the resistance 10 by connecting the high potential source 8 to the lower end of the winding 9, instead of to the middle.