GB433089A - Improvements in or relating to thermionic valves and circuit arrangements incorporating the same - Google Patents

Abstract

433,089. Thermionic valves ; circuits for wireless &c. TELEFUNKEN GES. FUR DRAHTLOSE TELEGRAPHIE, 12, Hallesches Ufer, Berlin. July 5, 1934, No. 19819. Convention date, July 5, 1933. [Classes 39 (i) and 40 (v)] A valve, particularly for use in a superheterodyne receiver, has a cathode providing a main and an auxiliary discharge in different and preferably opposite directions, a grid partly or wholly surrounding the cathode and common to both paths, the main discharge path including the common grid and at least two grid-like electrodes, and the auxiliary path consisting of the common grid and an auxiliary anode. In one arrangement the common grid is of cylindrical shape surrounding the cathode which is preferably indirectly heated. The grid may have portions giving different mutual conductances, for example, they may be of different mesh or spaced at different distances from the cathode. As shown in Fig. 3, the common grid consists of a cylinder 3 with radial ribs 10 assisting the decoupling between the paths. The auxiliary anode 4 is curved. The control grid 6 has metal strip supports 13 preventing the deflection of electrons laterally. The two screen grids 5, 7 are combined to form an electrode of box shape. One or more of the grids, for example, the grid 5, may produce a variable mu effect. As shown in Fig. 5, the cathode 2 is flat, the grid 3 is a box with flat sides of different mesh, and the control grid 6 and anode 9 are of U- shape. The grids 5, 7 are combined to form a box, and a suppressor grid 9 is extended to form a box surrounding the grid 3 and auxiliary anode 4 for reducing interference by external fields. In the arrangement shown in Fig. 6, the common grid is in two parts 31, 3<11> connected by a condenser K in the valve or cap, so that the same alternating but different continuous potentials may be applied to them. The input circuit is connected with the control grid 6. An amplification regulating voltage A.V.C. is applied to the grid 31 through a resistance W, and local oscillations produced in the auxiliary path and the circuit L<1>C<1> are applied to the grid 3<1>. A resistance R, shunted by a condenser C<3> stabilizes the amplitude of the local oscillations. The connections to the grid portions 3<1>, 3<11> may be interchanged and the resistance W may be mounted in the valve or cap and connected between the grid 3<11> and the cathode.