GB438360A - Improvements in gas or vapour filled electric discharge devices and circuits therefor - Google Patents

Abstract

438,360. Thermionic valves; circuits. ROBINSON, J. A., 171, East Mosholu Parkway, North, Bronx, New York, U.S.A. May 11, 1934, No. 14299. Convention date, Dec. 29, 1933. [Classes 39 (i) and 40 (v)] A gas- or vapourfilled valve has a first grid surrounding the cathode charged to a positive potential less than the ionization potential of the filling, a second grid surrounding the first and oppositely charged, and an anode. In one form, a relay valve 1 has a cathode 2, a first grid 4 at six volts positive, a second grid 5 at thirty volts negative and an anode 6 at one hundred and twenty volts positive. The discharge is confined to the space inside the anode by mica members 8, 9 or by a transverse field. The valve 1 has a mercury amalgam filling and is supported by means of collars 10, 13 in an outer evacuated envelope 14. The grids 4, 5 may be slotted or perforated, and two or more amplifier units may be mounted in a single envelope. The relay is shown operated by a photo-cell 20 in the lead supplying the outer grid 5 with out-of-phase negative voltage. The inner grid is supplied with in-phase positive voltage from the potentiometer 23. With this arrangement, light incident on the cell causes an interruption in the discharge through the relay. If the photo-cell is placed in the lead to the inner grid, light incident on it initiates a discharge in the relay. The relay may be used for continuous control if the grids each comprise a large number of turns.