GB166241A - Improvements in thermionic devices for wireless telegraphy and telephony - Google Patents

Abstract

166,241. Round, H. J. Aug. 7, 1919. Vacuum tubes.-A thermionic valve has a " grid anode " G, Fig. 1, of large area, maintained at a positive potential, and a second anode A, beyond, and as near as possible to the '' grid anode," the distance between the two anodes not exceeding one-fifth of the distance between the " grid anode " and the filament F; such a valve has a low resistance. A control grid may be interposed between the two anodes. In the arrangement shown in Fig. 4, the " grid anode " is in the form of a wire G wound around two opposite sides s of a steatite former having the shape of a parallelepiped, the control grid g being wound around the other two sides S, which are deeper than the sides s. The anode consists of two square plates A supported by pins a on the former. The filament F is mounted in the centre of the former. In another arrangement, the " grid anode " and control grid are of prismatic shape, and are stretched on four supporting rods of steatite, glass, or metal, and surrounded by the anode. In a further modification, the anode, " grid anode," and control grid are flat, and are spaced by flat steatite supports. In the circuit arrangement shown in Fig. 5, an oscillatory cirsuit O, receiving the incoming oscillations, is connected between the control grid g and the filament F, the " grid anode " being maintained positive by means of a battery B, and the anodefilament circuit A, F including a battery band 'an oscillatory circuit o operating a detector. In another arrangement in which no central grid is used, the oscillatory circuit receiving the incoming signals is connected directly with the anode, and with the filament through an oscillatory circuit operating a detector, a battery being connected between the grid anode and the filament so as to maintain the " grid anode " positive.