US2033112A - Electron discharge device - Google Patents

Description

March 16, 1936.

ELECTRON DISCHARGE DEVICE Filed Jan. 27, 1934 M /5 /4 Z Z 4 H l5 ,4 Q) m f 3 D= /4 l I i: /z 6 14 i) H K 5 E l4 [email protected] WWW? RICHARD W.CARLISLE R. w. CARLISLE 2,033,112

Patented Mar. 10, 1936 UNITED STATES PATENT OFFIQE ELECTRON DISCHARGE DEVICE of Delaware Application January 27, 1934, Serial No. 708,622

8 Claims.

My invention relates to electron discharge devices, and more particularly to electron discharge devices for use at very high frequencies.

The maximum frequency at which the conventional tube will operate is limited principally by the interelectrode and interlead capacity and by the inductance of the leads to the electrodes, because the inductance and capacity of the electrodes and leads form an electrical system whose natural frequency determines the upper limit of frequency at which the tube will operate. The interelectrode capacity may be decreased and thus the upper frequency limit at which a tube will operate increased by making the electrodes small, making them short, and bringing out the leads at different points on the bulb, but such a .tube is difficult and expensive to make, and its power output is limited.

The principal object of my invention is to provide an improved electron discharge device useful at very high frequencies and having a power output which is high compared with the output of a conventional type of tube operating at high frequencies.

In the preferred embodiment of my invention I make the effective capacity of the tube small enough to permit operation at much higher frequencies than the conventional tube and at the same time obtain a relatively high power output, by providing the tube with a multi-section anode or a multi-section grid or both, with lumped inductors electrically connecting the sections in series.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims, but the invention itself will best be understood by reference to the following description taken in connection with the accompanying drawing in which:

Figure 1 is a diagrammatic vertical cross-section of an electron discharge device embodying my invention, and Figures 2, 3, and 4 are diagrammatic representations of modifications of the embodiment of my invention shown in Figure 1.

Figure 1 shows an electron discharge device with a bulb l0 enclosing an electrode assembly comprising a conventional uni-potential cathode H, a grid l2, and an anode concentric with and surrounding said grid and cathode. In accordance with my invention the anode is a multisection electrode and comprises a plurality of annular sections I3 set end to end. These sections may be supported and spaced in any convenient way, for example, by insulating glass beads 14. The anode sections are electrically connected in series by lumped inductors l5. By proper design and proportioning of the anode sections and of the inductors the effective interelectrode. capacity of the tube is reduced without correspondingly reducing the output, as the electrodes are of substantially the same size as in the conventional tube.

It may be necessary in some cases to insure proper operation of the tube to segregate the capacity between the leads in the press from the interelectrode capacity, and this can be done by placing inductors l8 and I9 in the anode and grid leads between the press and the anode and grid electrodes.

In the arrangement above described at the resonant frequency, the voltage in each section of the anode will differ in phase, usually by 180, from the voltage in each adjacent section. In order that the voltages in the anode sections may be in phase, capacity in the form of condensers l6 may be connected between the midpoint of each inductor l5 and ground, such as the cathode H. A convenient way of making this ground connection is to provide a conductor or bus bar I! connected to the cathode and to one side of each of the condensers I6, the grid having wider spaces between the turns opposite the inductors as shown to facilitate connection of the bus bar H to the cathode and to permit as short a connection as possible between the condensers l6 and cathode II. In this way the voltage phase in each anode section is so controlled that the voltages in all the sections of the anode are in phase.

In any vacuum tube operating in an oscillating system, resonance occurs when the inductive and capacitive reactance of the tube and associatedcircuit elements is high enough and the cathode emission is low enough to give an effective resistance across the tube which is high compared to the inductive or capacitive reactance. While I do not wish to be restricted to any particular theory, it is my opinion that in a tube made in accordance with my invention, with the respective inductors and capacitors in which each alternate capacitor is a section of the plate (or a section of the grid), the structure will at the resonant frequency act as an iterative electrical transmission network in which successive capacitors are approximately 180 out of phase, and, therefore, the successive sections of the plate (or of the grid) are rotated 360 in phase, which is equivalent to zero phase, The tube just de- 55,

scribed is suitable for use as a radio frequency amplifier, especially at the particular high frequency to which it responds.

Figure 2 shows a modified form of tube having, in addition to the multi-section anode shown in Figure l, a multi-section grid which may be concentric with the cathode and comprising grid coil sections 20 electrically connected in series by inductors 2|. The anode sections l3 are coextensive with the corresponding sections 20 of the multi-section grid. In this modified tube the voltages in the sections of the grid are brought in phase with each other and the corresponding sections of the anode by means of condensers 22 connected between the midpoint of the inductors 2| and the cathode. This modified tube is also suitable for use as a radio frequency amplifier especially at the particular high frequency to which it responds.

Figure 3 shows another modified form of tube having a multi-section grid, but only a single section anode 23. This construction may be advantageous where the grid to cathode capacity is the limiting factor in the operation of the tube at high frequency. The voltage in the various sections of the grid are brought into phase with each other, as described above, by means of the condensers 22 connected between the center points of inductors 2| and the cathode H.

Figure 4 shows a still further modified form of tube having both a. multi-section anode and a multi-section grid, both of which may be concentric with the cathode I I The grid and anode sections are coextensive with each other in this modified tube. The voltages in the corresponding sections of grid and anode are in phase with each other and hence condensers to obtain proper phase relation are not necessary. This modified form of tube is adapted to work at all frequencies up to its limiting frequency.

It will be apparent that by means of my invention the effective interelectrode capacity of the tube, which was one of the principal limiting factors in high frequency operation of the tube, is reduced to such an extent that satisfactory operation of the tube at very high frequency with a relatively high output is possible. While my invention is shown applied to a triode, it is obvious that it is applicable to diodes as well as other multi-electrode electron discharge devices.

While I have indicated the preferred embodiments of my invention of which I am now aware, it will be apparent that my invention is by no means limited to the exact forms illustrated or the use indicated, butthat many variations may be made in the particular structure used and the purpose for which it is employed without departing from the scope of my invention as set forth in the appended claims.

What I claim as new is,

1. An electron discharge device having a cathode, an anode electrode, and a grid electrode,

one of said electrodes comprising a plurality of sections, lumped inductors electrically connecting said sections in series and a condenser connected between the midpoint of each inductor and the cathode.

2. An electron discharge device having a cathode, an anode comprising a plurality of sections, inductors electrically connecting the sections of the anode in series, a grid comprising a plurality of sections and inductors electrically connecting the sections of said grid in series.

3. An electron discharge device having a cathode, an anode comprising a plurality of sections, lumped inductors electrically connecting the sections of the anode in series, a grid comprising a plurality of sections, lumped inductors electrically connecting the sections of the grid in series, and a condenser connected between the midpoint of each inductor and the cathode.

4. An electron discharge device having a cathode, and an anode concentric with said cathode and comprising a plurality of sections, and inductors electrically connecting the sections of said anode in series.

5. An electron discharge device having a straight thermionic cathode, and an anode concentric with said cathode and comprising a plurality of sections, lumped inductors electrically connecting the sections of the anode in series, and a condenser connected between the midpoint of each inductor and the cathode.

6. An electron discharge device having a cathode, a grid concentric therewith, and an anode comprising a plurality of sections concentric with said cathode and said grid, lumped inductors electrically connecting the sections of the anode in series, and a condenser connected between the midpoint of each inductor and the cathode.

'7. An electron discharge device having a cathode, and an anode comprising a plurality of sections, insulating members spacing and supporting the anode sections, lumped inductors electrically connecting the sections of the anode in series and a condenser connected between the midpoint of each inductor and the cathode.

8. An electron discharge device having a cathode, a grid comprising a plurality of sections, and an anode comprising a plurality of sections, lumped inductors electrically connecting the sections of the grid in series, and other lumped in ductors electrically connecting the sections of the anode in series.

RICHARD W. CARLISLE.

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