GB534576A - Improvements in or relating to electron discharge apparatus - Google Patents

Abstract

534,576. Valve circuits. STANDARD TELEPHONES & CABLES, Ltd., SHANNON, D. S. B., and CHATTERJEA, P. K. Sept. 8, 1939, No. 25428. [Class 40 (v)] The auxiliary cathode and the collector electrode of an electron-multiplier are connected to separate output circuits, and the auxiliary cathode may be put out of action by reducing the voltage on an accelerating grid. As shown in Fig. 2, the valve is used in a combined transmitting and receiving circuit. The transmitter comprises an oscillatory circuit L2, C2 connected between the auxiliary cathode SE and the accelerating grid S, and an output circuit LC associated with the auxiliary cathode SE. The receiving circuit comprising an input circuit L1, C1 from the aerial and an output connexion from the collector electrode A. The receiver is always in effective connection, but the transmitter may be cut out by reducing by means of the potentiometer R1, the voltage on the accelerating electrode S. A remote transmitter may break in while the home transmitter is in operation, and the resulting heterodyne note may be used to control the potentiometer R1 and to cut out the home transmitter. When two transmissions such as television and sound are received on the same aerial, the valve V is used as a pre-amplifier, and the television and sound receiving circuits tuned to their respective wave-lengths are connected to the electrodes A and SE. One of the transmissions may be cut off by adjustment of the potentiometer R1, or the substitution of an alternative potentiometer, and the change may be effected by a switch on the panel, by a relay, or by remote control. The valve may be of the kind described in Specifications 484,900 and 524,049.