US2215779A

US2215779A - Electron tube and circuit employing it

Info

Publication number: US2215779A
Application number: US278205A
Authority: US
Inventors: Clavier Andre Gabriel; Rostas Ernest
Original assignee: International Standard Electric Corp
Current assignee: International Standard Electric Corp
Priority date: 1938-05-27
Filing date: 1939-06-09
Publication date: 1940-09-24
Anticipated expiration: 1957-09-24

Description

` Sept. 24, 1940. A G, CLAV|ER Er AL 2,215,779

ELECTHON TUBE ND CIRCUIT EMPLOYING IT Original Filed May 27, 1938 patented Sept. 424, 11940 UNITED STATES ELECTRON TUBE AND CIRCUIT EMPLOYIN G IT Andre Gabriel Clavier and Ernest Rosts, Paris, France, assignors to International Standard Electric CorporatiomNew York, N. Y.

Original application May 27, 1938, Serial No. 210,332. Divided and this applicationJune 9,

1939, Serial No. 278,205. n France May 6 Claims.

The present invention relates to new electron tubes and their utilisation and to circuitsemployed with such tubes.

` This application is a division of our copending application Serial No. 210,332, led May 27, 1938.

One of the objects of the invention is to improve the output and operation of ultra-high frequenoy systems, for example, employing frequencies corresponding to wave lengths ofthe order of the decimeter, the centimeter or even of values considerably lower as Well as frequencies of higher wave length.

In order to understand the nature of the present invention, it seems well to make some remarks with regard to the output of the electron tubes employed in particular as oscillators.

The output of the normal oscillator or amplifier tubes, that is to say, those in which the time of transit of the electrons remains short with respect to the period of the oscillation, is all the greater if the alternating tension between electrodes is a fraction higher than the direct tension in the source of supply (the output impedance being assumed to be ohmic).

By applying this reasoning to tubes in which the time of transitof the electrons is comparable to the period, there will be found a double limitation of the outputof these tubes. The first is the l diiculty in achieving output circuits of a sucient impedance to obtain these high tensions. This limitation is not directly bound up with the use of electronic oscillators. It is simply due to the high `frequencies which it is attempted to use. .The second on the other hand is directly connected with the method of opera-tion of` the' tubes. One of the conditions necessary for the operation of the present tubes is that the time of transit of the electrons should not depart too much from a mean suitable value related in a xed manner to the period. Now, this type of transit depends upon `the value of the alterhating tension superposed on the direct tension. inasmuch as the high frequency tension is small with respect to the direct tension, `the above condition is fuliilled. If it becomes comparable with l the direct tension it `considerably modiiies the time of transit of the electrons which leave at different moments in the period, and thus limits the amplitude of the oscillation. It .will consequently be seen that the high frequency tension must always remain small in proportion to the direct tension. Inmaccordance with this reasoning the output of the electron tubes will thus 55 seem theoretically limited to low values.

It is found, however, `that the condition offered by normal tubes of only being able to lead to a good output if the alternating high frequency tension becomes comparable with the direct tension is not inevitable in the case of electronic oscillators. This will be seen by considering not the output but the losses in the tubes and by seeking for the condition which leads to the is negligible the two expressions are equivalent since in this `case the speed of the electrons arriving on the positive electrode is equal to the tension of this electrode.

In the case in which the time of transit is comparable with the period the speed of the eleci trons arriving on an electrode is not always that corresponding to the potential of this electrode. This speed maybe higher or lower than the speed corresponding to the tension of this electrode. The difference of speed in proportion to the case of a negligible time of transit may become great, in spite of a low high frequency tension, in the case in which the electrons oscillate several times in thehigh frequency fields before arriving on the electrode. It iwill be seen that the instantaneouslosses in such a tube are no longer given by the `product ofthe instantaneous current by the instantaneous tension. They may be greater or smaller. This difference is supplied or absorbed by the oscillatory circuit. The t output of the tube thus no longer depends in` the same way on the high frequency tensionwon the terminals of the load. The output is increased if the speed of the electrons on arrival on the electrode is smaller than that corresponding to the potential electrode; it -is reduced if the speed is increased.

The present invention provides arrangements in which the electrons are systematically slowed down by one or more fields of high frequency, f

and thus supply `energy in one or` more oscillatory circuits, losing it themselves.

The present invention in accordance with one of its aspects thus permits the said limitations to be overcome; among others it provides an election these arrangements are such that the retardation of the electrons is produced in the system repeatedly under the action of the sa-me high frequency field, or fields, so as to increase the total energy given by the electrons concerned to the oscillatory circuit.

In accordance with another feature of the arrangement under consideration, the retardation of the mean speed of the electrons is produced by the magnetic or electro-magnetic high frequency field sustained by the energy given up by the slowing down of the average speed of the electrons.

The invention is not limited to the generation of ultra-high frequency waves and the tubes described here may be adapted to be employed for the generation amplification or detection as well as for various other applications, such for example, as in oscillographic systems or television systems, or for measuring apparatus.

The invention will be explained in detail in the case of the generation of ultra-high frequency waves, and indications will be given with regard to its employ in other elds.

The present invention will be better understood by means of the following description based on the attached drawing in which:

Fig. 1 shows a particular embodiment of the invention in which the electronic bundle advances in a zig-zag path; and

Fig. 2 is a section of the guide electrode structure of the device of Fig. 1, along the line 4 4.

Fig. 1 represents another embodiment of a device for the systematic retardation of the electrons comprising an evacuated envelope E in which are arranged an electron gun G, two pairs of deilecting plates D1, D2 operating in the ordinary way to produce and dene an electron bundle and two pairs of metal retarding plates R1, R2 respectively associated with metallic reecting electrodes P1 and P2. Fig. 2 shows a section of this gure along the line Fig. 1. The oscillatory output circuit O composed, for example, of a Lecher line is connected to each pair of retarding electrodes, and its middle point is connected to the electron gun G. The reflecting electrodes are connected to a source S3 of potential negative with respect to the cathode. Targets C1, C2 are placed on the two Lecher wires at the en'dof the structures'.

YThe bundle of electrons F passes between the electrodes R1 parallel to the surface of these electrodes, passes through the interval between the electrodes R1 and the electrodes R2 at a certain angle different from 90, then passes between the electrodes R2. On its approach to the reflecting electrode P2 at the outer edges of the electrodes R2 the bundle is returned to the space between R2 as shown, again passes between the plates R1 and is returned by the electrode P1. The bundle thus advances in zig-zag along the structure in order finally to strike one of the targets C1 or C2.

A tension U cos wt is assumed to exist between the pairs of electrodes R1 and R2. If the time between the two successive passages through the interval between the electrodes R1 and R2 is a half period the electrode will be retarded on each journey if it has been retarded on the rst journey. If the form of the electrodes is suitably chosen we then nd in consequence of considerations similar to those given for the tube of Fig. 1 that the electrons will be retarded on the average and will consequently supply energy to the oscillatory circuit composed of the tuned transmission line O.

If the form of the reflecting electrode P1 or P2 is suitably chosen the electro-static eld between the main electrode and the reecting electrode is such that it forms an electronic lens assisting to maintain the concentration of the electron bundle. This eld is represented schematically in Fig. 2 by means of its equipotential lines.

When we produce an oscillator device by the means which have just been described we have at our disposal a negative resistance effect which can be utilised in the amplification of electrical oscillations, for example, of the same order of magnitude as that of the oscillations which can be produced by the tube, when the conditions of operation are adjusted to be outside the range of conditions in which self-oscillation occurs.

In the case in which it is desired to employ such tubes as modulated oscillation generators it is possible to provide inside the tubes which have just been described electrodes having an influence on either the intensity or the direction of the electronic bundle or bundles employed.

Other arrangements within the spirit of the `invention and within the scope of the appended claims will be apparent to those versed in the art.,

What is claimed is 1. Electron tube arrangement comprising a source of electrons, a high frequency oscillatory circuit comprising co-extensive elongated electrode surfaces, and means for directing the electrons from said source in a sinuous path over said electrode surfaces and in the field thereof for the repeated retardation of the electrons and for the maintenance of oscillations in said oscillatory circuit.

2. Electron tube arrangement comprising a source of electrons, a pair of electrodes each comprising two substantially parallel plates, the respective plates of' one of said electrodes lying alongside and coplanar with the respective plates of the o'ther of said electrodes, a high frequency oscillatory circuit connected with said electrodes and means for directing the electrons from said source in a zig-Zag path entering the electrodes alternately for the maintenance of oscillations in said oscillatory circuit by the repeated retardation of the electrons.

3. Electron tube arrangement according to claim 2, including electrostatic means at the outer edges of said electrodes for reflecting the electrons entering said electrodes.

4. Electron tube arrangement according to claim 2 including converging reflecting electrodes bounding the zig-Zag electron path.

5. An electron tube oscillator comprising two pairs of spaced plates with the spaces between the plates in alignment and means associated therewith for setting up a high frequency field between said pairs of plates, means for directing a bundle of electrons between said pairs of plates in succession in zig-zag fashion for the repeated retardation of said electrons by the action of the eld between said plates, and means for utilizing the energy derived from the retardation of said electrons for the maintenance of electrical oscillations.

6. An electron tube oscillator according to claim 2 wherein said pairs of electrodes are of decreasing width in the direction of travel of said electrons whereby the amplitude of the zig-zag path decreases with the decreasing speed of the electrons.

ANDRE GABRIEL CLAVIER.

ERNEST RosTs.