GB127651A - Improvements in the Employment of Thermionic Devices for Magnification Purposes. - Google Patents

Abstract

127,651. Marconi's 'Wireless Telegraph Co., and Wright, G. M. May 12, 1917. Non-contact-making relays. Small currents or potential differences such as are set up in wireless receiving circuits are amplified by an arrangement of two or more vacuum-tube relays, of which the first has its plate connected to its grid through a high - resistance and a battery, the plate of the first relay also being connected to the grid of the second, the filament of the latter being connected to an intermediate point in the battery. The incoming current or potential difference is supplied to the grid g and filament f of the first relay, a potentiometer p determining the normal potential of the grid. The plate a is connected through a resistance r to the positive pole of a battery H, the negative pole of which is connected to the filament f. The plate a is connected also to the grid of the second relay, the filament of which is connected to a point m on the battery H, the potential at the point m being the same as, or differing by a small amount from, the normal potential of the plate a. Similar connexions are made between the second and subsequent relays, and the output circuit L<2>, C<2> is connected across the filament and plate of the last relay. The relays have a limiting action which serves to reduce disturbance from atmospherics. If an impulse is received which tends to give the plate a a considerable positive potential, current begins to flow from grid to filament of the second valve and the potential of the plate a is reduced. Similarly impulses of the opposite sign are damped at the third relay. These relays may be used for amplifying signals in ordinary cable telegraphy.