US2461250A

US2461250A - Electric discharge device and system

Info

Publication number: US2461250A
Application number: US632977A
Authority: US
Inventors: Francis M Bailey
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1945-12-05
Filing date: 1945-12-05
Publication date: 1949-02-08
Anticipated expiration: 1966-02-08
Also published as: GB644992A; BE472241A; FR937800A; NL75998C

Description

Feb. 8, 1949. F. M. BAILEY ELECTRIC DISCHARGE DEVICE AND SYSTEM 2 Sheets-Sheet 1 Filed Dec. 5, 1945 Inve'nbofi:

a B M .m c n H His Attorneg.

Feb. 8;1949. F. M. BAILEY 2,461,250

ELECTRIC DISCHARGE DEVICE AND SYSTEM Filed Dec. 5, 1945 2 Sheets-Sheet 2 {4 V i U '7 "I J3 J2 J2 CRYSTAL OSC/LL A701? 66 NEUTRAL a! If Q2 0 5 w '4 HisAotor-neg.

Patented Feb. 8, 1949 ELECTRIC DISCHARGEDEVICE AND SYSTEM 7 Francis M. Bailey, Scotia, N. Y., assignor to General Electric Company,

York

a corporation of New Application December 5, 1945, Serial No. 632,9 7?

My invention relates to improved electric discharge devices and systems therefor, and particularly to improved phase modulation discharge devices and systems.

In a known system of phase modulation a polyphase carrier wave is employed for energizing two sets of control electrodes which together with suitable focusing electrodes produce a disk of electrons having a rufiled edge. The rufile or deflection at the edge of the disk is essentially sinusoidal in form. Due to the polyphase energization of the system of electrodes the sinusoidal wave advances around the electron disk at the carrier frequency. An appropriate electron collecting electrode system receives the electrons of the disk selectively in accordance with the progression of the sinusoidal wave at the edge of the disk to produce an output voltage at the carrier'frequency. This voltage is modulated by a modulating magnetic field perpendicular to the plane of the disk of electrons to advance or retard the sinusoidal wave at the edge of the disk with respect to its unmodulated position. As will be readily appreciated by those skilled in the art, an alternating modulating signal is eifecz tive continually to advance and retard the phase position of the sinusoidal wave at the edge of the electron disk.

An object of my invention is to provide such a phase modulating electron discharge device having certain operating advantages and which, in addition, is less difiicult to manufacture.

In accordance with an important aspect of my 17 Claims. (Cl. 250-275) invention, the polyphase carrier voltage supply is provided with a neutral terminal and the discharge device is provided with one set of control electrodes for energization from the polyphase carrier voltage supply, and with a relatively simple control electrode structure for energization in accordance with the voltage of the neutral terminal of the carrier voltage supply.

It is an object of my invention to provide a new and improved electric discharge device and system.

It is another object of my invention to provide a new and improved electric discharge device for producing phase modulation of a carrier wave.

It is a still further object of my invention to provide a new and simple electrode structure for discharge devices of the type described above.

Further objects and advantages of my invention will become apparent from the following de-' scription when taken in connection with the accompanying drawings and its scope will be pointed out in the appended claims. I

In the drawings, Fig. 1 is an elevational view of an electric discharge device embodying my invention; Fig. 2 is an enlarged view, in section, of a portion of the electric discharge device shown in-Fig. 1 showing in detail the electrode assembly; Fig. 3 is a sectional view taken along the line 33 of Fig. 2; Fig. 4 is a sectional View taken along the line 44 of Fig. 2; Fig. 5 is a development of one of the electrodes of the devices shown in Figs. 1 to 4; Figs. 6 and 7 illustrate schematically the electron pattern under certain operating characteristics of the device; Fig. 8 illustrates diagrammatically a frequency modulating system embodying my invention; and

5 Fig. 9 is a development of a three-phase collecting electrode system.

Referring now to Figs. 1 to 4 of the drawings, I have shown my invention embodied in an electric discharge device including an evacuated envelope I to the lower end of which is secured a conventional base 2 including a plurality of contact prongs 3 and an orientation protuberance 4. The electrode assembly of the discharge device which is supported from the stem press (not visible in the drawing) by lead-in conductors 5 will now be described with particular reference to the enlarged views of Figs. 2 to 4. The assembly includes a pair of concentrically arranged anode or collecting electrode members 6 and I which are clamped between a pair of mica washers 8 and 9'by the planar marginal portions of a pair of focusing and modulating electrode elements l0 and Il. The electrodes l0 and II and washers 8 and 9 are clamped together at spaced points by suitable connecting links I2, which are secured at opposite ends to angle members l3 which are, in turn, secured to the marginal portions of the electrode members I 0 and II. The members l0 and II are formed of a material of reasonably high permeability such as steel, and comprise planar marginal portions and centrally located circular flange portions 14 and I5 defining central openings of gradually decreasing diameter. The members Ill and II are assembled with the flange portions l4 and i5 directed inwardly to provide a control gap between the inner ends thereof. V

A polyphase control electrode assembly is positioned in the opening defined by the flange portion 14 of electrode [0 by means of a mica washer I6 supported from the lower side of the electrode Ill by three supporting members I'!, which are welded or otherwise secured to the flange portion l4 andwhich are provided with projections l8 bent over against the outer surface of the washer [6. The electrode assembly includes a hollow cylindrical focusing electrode 19 having a flanged lower end portion 2! clamped to the inner surface of the washer l6. Surrounding the focus ing electrode is an assembly of control electrodes, which, in the specific embodiment illustrated, in-

cludes thirty-six wire-like elements 2| supported v The particular tube illustrated is designed for energization from a three-phase carrier voltage supply and the electrode members 2| are, therefore, arrangediin three sets, withthe individual conductors each conductively connected together andxmutuallyinsulated with respect to the conductors of'the other sets. In order to accomplish this electrical connectiorneach. of the conductors 2| is provided with a radiallyextending portion for connection with a conducting disk. As fllustrated in the. drawing, every third conductor is connected with a conducting apertured disk 23. The conductors adjacent these conductors on one side are connected with asecond conducting disk 25 and the remaining conductors are connected with a third disk 25. These disks are insulated from one. another andirom the electrode I! by suitable insulating disks '26 The disks 23,- 24 and 25, each provides a common terminal for the respective set of conductors, there being three sets. These disks and the respective sets of conductors, which are mutually insulated, are connected with different ones of thelead-incon-- ductors by conductors 21, 2% and 28, respectively. The radially extending portions of electrodes 2i connected with the different

treminal disks

23, 25 and 25 are located at different levels so that the stacked arrangement of terminals illustrated is provided.

'An electrode assembly is supported from the upper electrode I i in a mannersimilar to that just described in connection with the lower electrode Ill. The upper assembly includes a supporting mica washer 36 to which is secured a cylindrical focusing electrode 3!, which is identicalwith the iocusing'electrode it of the lower assembly. The washer Si! is supported from the disk H by suitable members 32, which may be of the same construction as the members ii. In the upper assembly a single planar electrode 33 of annular form and having a surface substantially co-extensive with that occupied by the radial portions of the wire-like electrodes 2! is provided. This electrode is supported concentrically; and in insulated relation, with respect to the focusing electrode 3i by means of a plurality of supporting wires 34 (three in the illustrated embodiment), which are secured to an upwardly extending collar 35 on the electrode 33, and which are bent over at their upper ends to engage the upper surface. of the mica washer 30. The wires 35 clamp the electrode 33 against the lower surface of an insulating Washer'B-E, which is held in position on the focusing electrode 3! by collar 3! secured to the outside of the focusing electrode M. The washer 36 centers the focusing electrode 3! and the control electrode 33 with respect to the elec-v trode [6. A supply connection for the control tend from the lower end thereof.

4 electrode 33 is provided by a conductor 38 which extends through the upper washer 3B.

A source of electrons is provided in the region between the inner ends of the focusing electrodes l9 and El to radiate electrons outwardly radially between the upper ends of the control electrodes 2i and the planar electrode 33 to form a disk of electrons. This source is provided by an indirectly heated cathode sleeve 39, which is supported concentrically within the focusing electrodes is and 3! by means of the insulating washers it and St].

The cathode may be provided with an oxide coating and heated by an insulated heater element received within the sleeve 39 and provided with terminm conductors 38 and ii, which ex- The terminal conductors 453 and 'll are connected with separate ones of the lead-in wires 5 and the cathode sleeve is connected by conductors 32 to one of these lead- Upper'iocusing electrode 3: is connected with lower focusing electrode l9 and to a lead-in conductor 5 by

conductors

43 and 54 shown in Fig. l. The upper planar control electrode 33, which in operation is connected with the neutral" of the polyphase carrier supply voltage, is connectedto a lead-in conductor 5 by a conductor t5, shown in Fig. l, which connects with conductor 38. s

The upper and lower focusing and modulating electrodes id and ii are electrically connected together by the links :2 and to a lead-in conductor 5 by a conductor 46 secured to one of the angle members [3. c c I A cylindrical shield 41 of substantially the diameter of the lower supporting washer Iii is secured to the lower electrode ii and electrically connected thereto. The member ll shields the conductors 27, 2'8 and 29 which are adapted to be energized from the polyphase carrier supply voltage from the output connection which are connected respectivelywith the anodes or collecting electrode membersfi and i. p

In Fig. i only, the supply conductors 2i and 28 connected with the polyphase electrode system are visible, and only .conductor 53, which is connected with the collecting electrode 6, is shown on the exterior of the shield member. It .will be understood that the-conductor Q9 of Fig. 2 connects the collecting electrode 2 with a separate lead-in conductor 5 and that the conductor 29 is connected with a lead-in conductor.

The modulation of the output voltage appearing across the collecting electrodes 6 and l is effected by a magneticfield produced between the opposedend portions of the flanges l4 and ii": of themodulating and focusing electrodes .1 Sand ll. As indicated earlier in the specification, these membersare formed of amaterial of high p.ermo-, ability and provide a magnetic circuit for a modulating coil iii! which surrounds the envelope of the device in the region, of the outer edges of the electrodes it and I 1. They serve to carry the magnctic flux o f coil 5d inward and to ooncentrateit at right angles to theelectron disc in .a circular region J'ustoutsideof and between the peripheries of planar electrode 33 and the electrode assembly 2 l, 22. V

Inforder that the 'electronswmay be collected selectively by the electrodes 5 and 'l in accordance with 'the deflections produced by the various electrodes of the control system, the inner- .collecting electrode fi is .provided 'with two,se ts..5.l and 52 of substantially rectangular openings. As indicated in the drawing, the openings of both spect to each other on oppositesides of a median line. The spacing between adjacent-openings in each set is equal to the width of the'openings so that each opening of one set is opposite a space between adjacentopenings of the otherset.

The manner in which the electric discharge de-. vice of the illustrated embodiment of my invention operates to phase modulate a carrier voltage wave will now be briefly described. The electrons emitted from the central portion of the cathode sleeve 39 pass radially outwardly between the op-' posed ends of. the cylindrical focusing members I 9' and 3| and through the region bounded on one side by the annular planar electrode 33 and on the opposite side by the polyphase system of control electrodes including the wire-like control members 2 l. The electrons next pass between the opposed ends of the focusing and modulating electrodes Ill and l l and continue to the collecting electrodes 6 and 1. The first focusing electrodes l9 and 3| assist in neutralizing the space charge around the cathode and also tend to confine t e electrons to a relatively narrow region in an axial direction. With the control electrodes 2| connected to provide a three-phase system, a rotating electrostatic field is produced in the region between the radial portions of these electrodes and the face of the annular electrode 33, which latter electrode is adapted to be connected to the neutral of the carrier voltage supply and which may therefore be termed a neutral plane electrode. This field is effective to produce a deflection of the electrons in an axial direction and provide a sinusoidal ruffie at the edge of the electron disc having a space distribution determined by the space distribution of the control electrodes 2!. With the thirty-six electrodes provided in the illustrated embodiment, the edge of the disc takes the form of a sinusoidal ruflle made up of twelve complete cycles. A diagrammatic representation of the electron disc is shown in Fig. 6 in which the wall bounding the openin in the center represents the surface of the cathode39 and the control electrodes 2| are indicated diagrammaticallyby a circumferential array of equally spaced dots 2|. The rufiled disc is brought to a relatively thin edge by the electrostatic focusing action of the electrodes l and H.

The manner in which the electrons are selectively received by the collecting electrodes 6 and 1 will be readily understood from a consideration of Fig. 5 in which a portion of the electrode 5 has been developed.

Referring to Fig. 5, two

sinusoidal waves

53 and 54 having the spacial distribution of the wave at the edge of the electron disc have been represented with respect to the developed portion of the electrode 6. The wave 53 represents the edge of the electron disc at an instant when essen tially all of the electrons pass through the openings 5| and 52. Under. these conditions. the voltage of the collecting electrode 1 is a maximum and the voltage of the electrode 6 a minimum. The

dotted curve 54 represents the edge of the disc displaced 180 degrees .with respect to the edge of the disc represented bythe curve 53. It'will .be

noted that with this displacement essentiallyall.

the electrons are collected by the electrode 6 and that none of the electrons passes through the openings 5! and 52 to be collected by the elec trode 1. Under these conditions, the voltage of openings 5| and 52 are correlated directly withthe'number of control electrodes of the polyphase electrode system and the number of phase groups in which they are arranged; The dotted curve 54 represents the edge of the disk at an interval of time later than the curve 53 corresponding .to a half cycle at the carrier frequency. In other words, the voltage of each of the control electrodes 2| positionedopposite the crests of the waves as illustrated in Fig. 6 have changed from-a positive maximum to a negative maximum during the interval of time during which the edge of the disc has changed from the configuration represented by curve 53 to that represented bycurve 54.

In addition to the change in shapeof the electrons at the edge of the disc due to the rotating field produced by the polyphase system of electrodes and the neutral plane electrode 33, the wave at the edge of the disc may be advanced or retarded by the application of voltage to the modulating coil 55 which produces a magnetic field be-.

tween the opposed ring-like edges of the focusing and modulating electrodes H3 and H. As will be understood by those skilled in the art, an axial magnetic field will deflect the electrons tangentially. A diagrammatic representation of the effect on the electron disc of a unidirectional magnetic field of predetermined magnitude is illustrated in Fig. 7 Where the edge portion has.

been rotated in a clockwise direction with respect to the electrons making up the inner portion of the disc. It is apparent, therefore, that the distribution of the electrons collected by plates 6 and I in this instance is dependent not only upon the electrostatic field produced by the polyphase system of control electrodes 2| and the planar electrode 33 but also on the modulating electromagnetic field produced between the opposed edges of the focusing and modulating electrodes I0 and l I. It will be understood by those skilled in the art that an alternating modulating voltage applied to the coil 55 will cause a continual advance and retard of the wave at the edge of the electron disc with respect to that which it would occupy in the absence of a magnetic field, with the overall result that both phase and frequency modulation of the voltage appearing between electrodes 5 and 7 are produced. However, since a unidirectional voltage of constant magnitude applied to modulating coil 50 produces pure phase modulation of the output voltage between electrodes 6 and l, the tube is essentially a phase modulation tube.

In Fig. 8 I have illustrated a frequency modulating system embodying my invention. In the system shown in Fig. 8 the discharge device 55 is a diagrammatic representation of the device described previously in connection with Figs. 1 to '7. Electrode 51 corresponds to the outer collecting electrode 7; electrode 53 corresponds to the inner sponds to the modulating coil 50 shown in Fig. 1.-

' The discharge device as described above is connected in afrequency modulation system in the following manner. A voltage supply. for maintaining the various electrodes at appropriate direct current voltages is provided by

voltage dividing resistors

51, 68, 69, I and 1! connected in series between a ground connection. I2 and the Positive conductor '53 ofa source of direct current voltage. High frequency icy-pass capacitors! are connected between one terminal of each of the voltage dividing resistors and ground. As illustrated in the drawing, the cathode 65 is connected to the direct current ground. The

inside focus electrodes

53 and 64 are connected to'the positive terminal of resistor 67 which may be at -a positive voltage of the order of voltsand the outside focusing and modulating electrodes 6"!- and 62 are connected to the positive terminal of resistor 68 and may be maintained at a voltage of 59 volts. The neutral plane. electrode 33" is connected to the positive terminal of voltage dividing resistor 68 which may be 70 volts positive, for example. 'The positive terminal of voltage dividing resistor Ill is connected to the neutral terminal of the polyphase carrier supply voltage by conductor 16 to provide a direct current voltage differential between the neutral plane electrode 3| and the polyphase system of electrodes 2!", which are energized by the three-phase carrier voltage supplied by a single-phase to three-phase conversion circuit 15. The conversion circuit '55 as illustratedis energized by the output of a single-phasecrystal oscillator illustrated diagrammatically at 16.

The collecting electrodes 5? and 58 areconnected together by a center-tapped output coil H, which forms the primary winding of an output transformer 18 having a secondary winding 79 connected to a frequency multiplier and amplifier circuit, illustrated diagrammatically at Bil, which supplies the modulated carrier to an antenna 8|. The primary winding '17 is shunted by a capacitor 82 to provide an oscillatory circuit resonant at the carrier frequency. The mid-point of the transformer H is connected to the positive terminal of the voltage dividing resistor H, which may be at a suitable voltage, such as 250 volts.

In order to suppress secondary emission of electrons by the electrode 51, a self-biasing circuit including a parallel resistor 83 and a capacitor 84 is connected in the circuit with the inner collecting electrode 58 to maintain it at a substantial negative direct current voltage with respect to the outer collector electrode 5?. The modulating coil 66 is energized from a suitable source of signal voltage, such as the output of an audio amplifier indicated diagrammatically by the nu- :l

meral 85.

The operationof the system illustrated in Fig. 8 is believed to follow directly from the detailed description of the operation of the discharge device of Figs. 1 to 4. The utilization of a carrier supply having a neutral terminal and a discharge device employing a neutral plane electrode renders it possible to interpose a direct current voltage between these two electrode systems so that the undefiected edge of the electron disc may be lined up with the line separating the two groups of openings El and 52 of the inner collecting electrode, thus producing symmetrical alterhating voltage between the outputelectrodes 51 and 58. 7 It will be apparent that the present invention, in addition to affording the advantages just described in connection with the system of Fig. .8, provides a tube with many advantages over the prior art, particularly from the standpoint of staggered with respect to the openings 86.

simplicity of construction. .Some of the important. features contributing to the simplicity are theuse of the neutral plane electrode and the compactassembly in accordance with which the inner focusing and control electrodes are supported from the outer focusing and modulating electrodes vill and H as shown in Fig. 2. The assembly ofthe polyphase electrodes and assoelated terminal discs provided is also a feature of the invention.

. The collecting electrodesoi the discharge device may be constructed to provide a three-phase output. In Fig. 9 cylindrical electrodes of this type have been developed into a planar View. The inner. electrode, designated by the numeral 6', is in general similar to the inner collecting electrode 6 as shown in Fig. 2. However, instead of twelve openings in each set, the structure includes .three sets of three each electrically displaced from the preceding set by a distance corresponding to 120 electrical degrees or two-thirds of the width of one of the openings. Since the displacement precludes the possibility of using twelve openings, the total number of openings is reduced to nine,

' and'a portion of the cylinder is accordingly unused. As shown'in Fig. 9, the collecting electrode includesin the first phase group three openings 86 above the center of the electrode and three openings 87 below the center of the electrodeand As in the case of electrode ihthe width of the openings is equal to the space between them. The second set of openings, corresponding to the second phase ofthe output, are displaced 120 electrical degrees with respect to the openings 86 and 81.

As indicated, the first opening of the upper set 38 of the second group is displaced from the last opening 8'! of the preceding phase group. In a similar manner, the first opening of the upper set of openings 83 of the third phase group is displaced 120 degrees with respect to the last opening of the lower set 93 of the second phase group. The lower openings of the third group are designated by the numeral 9!. In order that the displaced voltages may be collected and supplied to separate output terminals, the collecting electrode corresponding to the outer electrode 1 of 'Fig. 2, for example, is formed in three sections I located respectively behind the three groups of displaced openings. These sections, designated by-the -numerals'92, 93 and 94, are indicated by dotted lines in Fig. 9. It will be understood that three output circuits will be provided for the electrode system of Fig. 9 with one terminal of each circuit connected to the common electrode 61, and the other terminal of each of the circuits connected to the three

electrode sections

92, 93 and 94. a V

While I have shown and described a particular embodiment of my invention, it will be obvious to those skilled inthe art that changes and modifications maybe made Withoutdeparting from my. invention in its broader aspectsand I, therefore, aim in the appended claims to cover all such changes and modifications as .fall within the true spirit and scope of my invention. 7 r

WhatI claim as new and desire to secure by Letters Patent of the United States is:

v1. An electric discharge device comprisinga source of electrons including means for confining said electrons in a generally planar region, said means including electrode means positioned on opposite sides ofsaid region, aplurality of control electrodessupported in mutually spaced and insulated relation in a'p'lane on one side of said region and parallel thereto, a substantially planar control electrode lying in a plane on the opposite side of said region and in opposed relation to said plurality of control electrodes, and a pair of collecting electrodes for selectively collecting electrons emitted by said source in accordance with the energization of said control electrodes.

2. An electric discharge device comprising a source of electrons including means for confining said electrons in a enerally planar region, said means including electrode means positioned on opposite sides of said region, a plurality of control electrodes supported in mutually spaced and insulated relation in a plane bounding one side of said region, a substantially planar electrode lying in a plane bounding the opposite side of said region and in opposed relation to said plurality of control electrodes, and collector electrode means, said control electrodes being supported between said source and said collector electrode,

means.

3. An electric discharge device comprising a source of electrons including means for confining said electrons in a generally planar region, said means including electrode means positioned on opposite sides of said region, a plurality of control electrodes supported in mutually spaced and insulated relation on one side of said region, a substantially planar control electrode supported on the opposite side of said region abutting said plurality of control electrodes, a pair of collecting electrodes for selectively collecting electrons emitted by said cathode in accordance with the energization of said control electrodes.

4. An electric discharge device comprising an;

elongated cathode, a'plurality of electrodes supported in mutually spaced and insulated relation in a circular array concentric with said cathode and lying in a plane substantially perpendicular to the axis of said cathode, a substantially circular electrode supported concentrically with said cathode and spaced longitudinally of said cathode with respect to said plurality of electrodes, and collector electrode means surrounding said cathode and said control electrodes.

5. An electric discharge'device comprising an elongated cathode, a plurality of control electrodes supported in mutually spaced and insulated relation in a circular array concentric with said cathode, a substantially circular electrode supported concentrically with said cathode and spaced longitudinally of said cathode with respect to said plurality of electrodes, and collector electrode means surrounding said cathode and said control electrodes.

6. An electric discharge device comprising an elongated cathode, a plurality of radially extending control electrodes supported in mutually spaced and insulated relation in a circular array concentric with said cathode and lying in a plane i 10 directed inwardly and terminating in spaced relation, a cathode supported centrally in the openings defined by said flanges, and a coil surrounding said members for producing a flux in the gap between said flanges to control the electrons emitted by said cathode.

8. An electric discharge device comprising a substantially cylindrical collector electrode, a pair of members of magnetic material each including a marginal planar portion and a central flange portion defining an opening of gradually decreasing cross section, said members being supported at opposite ends of said electrode with said flanges directed inwardly and terminating in spaced relation, a cathode supported centrally in the openings defined by said flanges, and a pair of control electrode assemblies supported respectively in the openings defined by said members and between said cathode and said collector electrode. 1

9. An electrode assembly comprising a disklike member of magnetic material having a contrally located aperture defined by a flange of gradually decreasing diameter, an electrode assembly supported from said member and extending within said opening including a cylindrical electrode, an insulating spacer member surrounding said cylindrical electrode and engaging the inner Wall of said flange, and a disk-like electrode secured in engagement with said insulating spacer and in concentric relation with said cylindrical electrode.

10. A polyphase electrode assembly comprising an. insulating cylinder, a plurality of wire-like r electrode elements each element including a radial portion extending across a portion of one end of said cylinder and an axial portion lying along'the outer surface of said cylinder, said .elements being supported in uniformly spaced relation with the longitudinal portions of adjacent elements extending along thesurface of the cylinder at different distances, said conductors being arranged in symmetrical groups having longitudinal portions of equal lengths, a plurality of conductive washers surrounding said cylinder and supported in spaced insulated relation, the conductors of each group, being connected with a different one of the washers,

. '11. An electric discharge device system comprising cylindrical collector electrode means including mutually insulated complementary collecting surfaces, a source of electrons including means for confining said electrons in a relatively narrow region in the direction of the axis of said cylinder, a polyphase deflecting electrode system supported on one side of said region from said source and said collector electrode means, an electrode supported on the opposite side of said region, a polyphase supply of carrier voltage including a neutral connection, and means energizing said polyphase electrode system with the phase voltage of said supply and said electrode with the voltage of said neutral connection.

12. An electric discharge device system comprising cylindrical collector electrode means including mutually insulated complementary collecting surfaces, a source of electrons including means for confining said electrons in a relatively narrow region in the direction of the axis of said cylinder, a polyphase deflecting electrode system supported on one side of said region and between said source and said collector electrode means, an electrode supported on the opposite side of said region, a polyphase supply of car- I 1. rler voltage including a neutral connection, means energizing said polyphase electrode system'with "the phase voltagesof said supply and said electrode with the voltage of said neutral connection, and means comprising a unidirectional bias voltage between. said neutralconnectionand said electrode.

13. In combination, cylindrical collector electrode means including mutually insulated complementary collecting surfaces-a source of electrons including means'for confiningsaid electrons in'a relatively narrow region'in the direction of the axis of said'cylinder, a polyphase' deflecting electrode system supported between said source and said collector electrode means for producing a repetitive deflection of electrons provided 'by said source from one of said surfaces toithe other, and a self-biasing circuit connected with one of said surfaces to maintain it at a substantial negative voltage with respect to the other of said surfaces; 14. An electric discharge device comprising a pair of concentrically arranged cylindrical collecting electrodes, 2. pair. of apertured disks of insulating material positioned respectively on opposite ends of said electrodes, a pair of members of magnetic material, each of said mem-- bers comprising a marginal planar portion and a central flange portion defining a central opening,

said members being assembled on said disks with said flangesextending inwardly through the apertures of said disks and terminating in spaced relation to provide a central gap,-'and a cathode supported within the opening defined by said 15.'An electric discharge. device comprising a central opening, said members being assembled I respectively on said disks with said marginal portions in parallel relation and said flanges extending inwardly throughthe" apertures in said disks and terminating in spaced relation, a cathode supported centrally within the opening defined by said flanges, control electrode means '12 positioned between said cathode and said flanges for producing a deflection of the electrons emitted by said cathode and in an axial direction with respect to said cylindrical electrodes, and means cooperating with said members of magnetic material for producing a magnetic field between the ends of said flanges.

16. An electric discharge device comprising a pair of concentrically arranged cylindrical collecting electrodes, a pair of members of magnetic material, each of said members comprising a marginal planar portion and a central flange extending generally perpendicular to said marginal portion anddefining-acentral opening, said members being assembled respectively on opposite ends of said cylindrical collecting electrodes with said marginal portions in parallel relation and with said-flanges extending inwardly and terminating in spaced relation to provide a control gap, a cathode supported within the opening defined by said flanges, and control electrode means positioned between said cathode and said flanges for producing a'deflection of the electrons emitted by said cathode and in an axial direction with respect to said cylindrical electrodes.

17. A three-phase cylindrical electrode system for collecting electrons selectively in accordance with a repetitive displacement of the electrons in an axial direction comprising a cylindrical electrode having three sets of openings with each opening having a width corresponding to 180 at a predetermined frequency and with the first opening of the second and third groups displaced a distance corresponding, to 120 electrical degrees at said frequency with respect to the last opening of the preceding group, and three mutually insulated electrode means supported outside of said cylindrical electrode.

FRANCIS M.

REFERENCES CITED UNITED STATES PA'in 'rs BAILEY.

Number Name Date 2,129,710 Soller; Sept. 23, 1938 2,151,765 Hellman Mar. 28, 1939 2,322,556 Ziebolz June 22, 1943 2,391,967 Hecht et al Jan. 1, 1946