GB307558A - Improvements in thermionic valves - Google Patents

Abstract

307,558. Midgley, A. H. Dec. 19, 1927. Vacuum tubes.-A multiple valve has a cathode of U, V, or M-shape, a power-amplification electrode system consisting of an anode and one or more grids being associated with the central part of the filament, and an electrode system for detection or low-power amplification being associated with the two adjacent ends of the filament, the electrode systems being so disposed that interaction between them is negligible. As shown in Fig. 1, the cathode 1 is surrounded by a grid 5 and an anode 4, both being preferably of flattened cylindrical shape. The detector or low-power amplification stage consists of an anode 6 in the form of a rod or plate, and a grid 7, both mounted between the ends of the filament. The grids do not extend beyond the ends of the corresponding anodes, thereby avoiding interaction. The grid 5 may be connected with the anode 6 either directly or through a blocking condenser which may be mounted within the envelope. In a modification two electrode stages may be associated with the adjacent ends of the filament, one stage with each end. Thus the anodes may consist of flat or curved plates arranged outside or within the ends of the filament, and the grids may be arranged between the filament and anodes or around the filament; interaction between these sets of electrodes may be produced as described in Specification 280,981, while avoiding interaction with the electrodes of the high-power stage.