US1945639A

US1945639A - Discharge tube

Info

Publication number: US1945639A
Application number: US641796A
Authority: US
Inventors: Holden William Henry Towne
Original assignee: American Telephone and Telegraph Co Inc
Current assignee: AT&T Corp
Priority date: 1932-11-08
Filing date: 1932-11-08
Publication date: 1934-02-06
Anticipated expiration: 1951-02-06

Description

Feb. 6, 1934. w. H. T. HOLDEN DISCHAARGE TUBE Filed Nov. 8, 1932 INVENTOR 1 EZFoldn ATTORNEY Patented Feb. 6, 1934 DISCHARGE TUBE William Henry Towne Holden, Brooklyn, N. Y., assignor to American Telephone and Telegraph Company, a corporation of New York Application November 8, 1932. Serial No. 641,'796

3 Claims.

*This invention relates to electrical discharge devices, and more particularly to that class of discharge devices containing a gaseous filling, such for example as a monatomic gas or metallic vapor, at a reduced pressure, and provided with a cathode, control electrodes and an anode so arranged that variations in potential of the control electrode cause corresponding variations in anode current.

such devices have been described in the past, and have ordinarily required either a heated thermionically emitting cathode or an auxiliary mercury arc, the cathode of which also serves as the cathode of the controlled current. It is one of the objects of this invention to substitute a glow discharge between cold electrodes for the arc discharge between a thermionic or mercury pool cathode and the auxiliary anode, which is also employed. But by utilizing a cold cathode :go discharge I am enabled to so arrange the electrodes that a materially Simpler Construction is possible, avoiding the difficult Construction required in the mercury are type of amplifier. Other objects and features of this invention will become apparent from the following detailed description of the invention.

The invention may be more ully understood from the following description together with the accompanying drawing in the Figs. 1, 2, 3, 4, and 5 of which the invention is illustrated. Figs. 1 and 2 show the Construction of control electrode assemblies. Fig. 3 shows a plurality of control electrode assemblies mounted on a single stem. Fig. i shows the arrangements of Fig. 3 sealed into a tube. Fig. 5 is a cross-section of Fig. 4.

` Similar reference characters have been utilized to denote like parts in all of the figures.

Referring to the appended drawing, Figures l and 2 illustrate the Construction of a control electrode assembly. A glass tube l is sealed H about anode lead 2 at its upper end. A errule 4 to which grid lead 3 is attached surrounds the upper end of this seal. At the top of the seal and fitting tightly against the end of the glass is anode 7. Lead wire 2 is carried through the anode and welded thereto at the top, forming a the grid meshes. Electrons, however, will pass freely into the interior of the hollow cylind rical grid structure and reach anode 7. The number of electrons thus reaching anode '7 may be, controlled by the potential of grid 6. The space between anode 7 and grid 6 is of such dimensione' that it is small Compared with the mean free path of an electron in the gas at the pressures employed. Positive ions will, therefore, not be ormed inside grid 6 and the current to anode 7 will be purely electronic and continuously controllable by the potential applied to grid 6.

The electrode assembly of Figs. 1 and 2 may be immersed in the positive column of a glow discharge by being sealed inside of a tube containing a monatomic gas and a cathode and anode with a suitable source of potential connected between them. Any desirable type of discharge tube may be used.

A plurality of the control electrode assemblies may be supported on a single reentrant stem 9,

adapted to be sealed into a bulb 14, as shown in' Figs. 3 and 4. Each of these electrode assemblies 10, 11, 12 and 13 has its own grid and anode leads. Fg. 4 shows how a stem such as that of Fig. 3 may be sealed into a bulb 14, into the other end of which has been sealed a stem 16, carrying a cathode 15 and an auxiliary anode 17, the latter being only visible in the Fig. 5 which represents a cross-section of the bulb shown in Fig. 4 along the section line 1-1. Projections 20 from the interior of cathode 15 shield the grids of the

electrode assemblies

10, 11, 12 and 13 from each other.

An auxiliary source of potential applied by

conductors

18 and 19 between anode 17 and cathode 15 respectively maintains a glow discharge therebetween, and in such a manner that the electrode assemblies 10, 11, 12 and 13 are immersed in the positive column thereof. Each of the said assemblies, consisting of a grid and anode, together with the common cathode constitute a threeelement amplifier, and may be used independently, in cascade, or in parallel as required, if suitable input and output crcuits be provided and if the anodes of these electrode assemblies be supdischarge between cold electrodes. As is well known, the positive column of an arc discharge and of a glow discharge are substantially alike in properties, and it therefore is evident that the principles of this invention may be applied to a tube in which the auxiliary discharge, from which the electron current for the control anode is obtained, is maintained between a hot cathode and a cold anode. Referring to Fig. 5, if 1'7 be assumed to be a thermionically emitting hot cathode and 15 the anode of the auxiliary discharge, it is obvious that this device will operate in the manner already described, when the cathode is heated to an emitting temperature and an arc is maintained between the said cathode and anode.

While the invention has been disclosed as embodied in certain specific forms which are deemed desirable, it is understood that it is capable of embodiment in many and other widely Varied forms without departng from the spirit of the invention as defined by the appended claims.

What is claimed is:

1. A gas-filled discharge tube comprising a plurality of electrode assemblies supported inside of said tube, each of said. electrode assemblies comprisng an anode and a grid completely enclosing said anode, and means for starting a glow discharge in said tube in which all of said electrode assemblies will be immersed.

2. A gas-filled discharge tube comprising a plurality of electrode assemblies supported inside of said. tube, each of said electrode assemblies comprising an anode and a grid completely enclosing said anode, means for starting a, glow discharge in said tube in which all of said electrode assemblies will be immersed, and means for shielding the grids of said electrode assemblies from each other.

3. A gas-filled discharge tube comprising a plurality of electrode assemblies supported inside of said tube, each of said electrode assemblies comprising an anode and a grid completely enclosing said anode, a cylindrical cathode surrounding all of said electrode assemblies, a cylindrical auxiliary anode coaxially placed with respect to said cathode whereby a glow discharge may be maintained in said tube in which all of said electrode assemblies will be immersed, and electrostatic shields between said electrode assemblies.

WILLIAM H. T. HOLDEN.