US1565416A - Electron-tube oscillator - Google Patents

Description

Dec. 15, 1925. 1,565,416

L. W. CHUBB ELECTRON TUBE OSCILLATOR Filed Feb. 14. 1921 Fig.2.

WITNESSE Z INVENTOR 4' lenlglflarr/kyfalzb'lzllbb.

Patented Dec. 15,, 1925.

um'rsn STATES PATENT. OFFICE.

LEWIS WARRINGTON CHUBIB, or nnenwoon PARK, PENNSYLVANIA, AssIGNoR T0 WESTINGHOUSE ELECTRIC 6; MANUFACTURING. COMPANY, A conPonA'rIoN 011' PENNSYLVANIA.

ELECTRON-TUBE OSCILLATOR.

Application filed February 14, 1921. Serial No. 444,636.

have invented a new-and useful Improve;-

ment in Electron-Tube Oscillators, of which the following is a-specification.

My invention relates to wireless transmission systems and particularly to vacuumtube oscillation generators employed'in connection with such systems.

The object of my invention is to provide an oscillation generator of the aboveindicated character thatshall be simple in construction, reliable in operation and of a higher efiiciency than has heretofore been obtained in such tubes.

In the present type of vacuum tube em ploying a single anode. a limiting feature in the design of the tube is the maximum operating temperature of the anode.

As is well known, a large portion of the energy supplied to the plate-filament circuit is lost as heat at the anode. *At present, by reason of the large heat losses incurred, the maximum operating efiiciency of the threeelectrode vacuum-tube is approximately 50%. This means that practically one half the energy supplied to the vacuum tube is lost as heat at the anode.

The maximum temperature at which the material constituting the anode may be operated is limited first; by the melting point of the material and second; by the rate of evaporation of the material. 5 According to my invention, I provide an oscillationgenerator in which a plurality of anodes are employed to reduce the w0rkingtemperature of the individual anodes, thereby permitting a greater energy input to the vacuum tube without undue heating. Briefly speaking, my invention comprises a plurality of plate elements, asource of: electron emission and means included in an oscillatory circuit whereby an electron stream may be selectively controlled to impinge upon predetermined groups of the plate elements to' cause the oscillations in the oscillatory circuitto be sustained.

My invention may best be understoodby,

reference to the accompanying drawings, in which:

Fig. 1 is a diagrammatic viewof circuits and apparatus embodying my invention.

Fig. 2 is a view, partially diagrammatic and partially. structural, showing my invention as applied to a wireless-transmission system.

Referring to Fig. 1, an oscillation generator 1 comprises an electron-emitting cathode 2 and a plurality of curved anoiie elements or plates 3 and 4 which are disposed alternately around the inside periphery of the vacuum-tube device 1 and are inclined in opposite directions with respect to a line connecting the cathode 2 with the respective anode elements Sand 4. i The anode elements 3 and 4 are connected in parallel relation by means of conductors 5 and 6, respectively. The hot cathode 2 may be energized by means of a battery 7 through a resistor &

A high-frequency oscillatory circuit, which is connected in shunt relation to the groups of plate elements 3 and 4, comprises a variable capacitance 9, an inductance'coil 11 and a balance coil 12. The inductance coil 11 is so disposed that the magnetic field therefrom is transverse to, the electro path, and the intensity of the magnetic field, at the surface of the hot cathode 2, is substantially zero. i

An electrostatic field is produced between. the hot cathode 2 and the plurality of plate elements 3 and 4 by means of a sourceof energy 13 which is included in a circuit that extends from the hot cathode 2 to the lurality of plate elements 3 and 4 throng a conductor 14, the source of energy 13, a balance coil 12 and the conductors 5 and 6, respectively. v

Referring to Fig. 2, the arrangement shown difiers from'that of Fig. 1 by reason of the fact that the capacitance of the condenser 9 is replaced by that of an antenna 15. In this arrangement, I have. shown the coil 11 so di magnetic fie d that is substantially zero at the surface of the hot cathode 2. The oscillatory circuit" includestheantenna 15, a

osed as to produce a transverse variable inductance coil 16, the inductance coil 11, the balance coil 12 and a ground lead 17.

In the operation of my invention, I utilize the well known effect of a transverse magnetic field upon the path of an electron stream. In a vacuum-tube device comprising a central filament and a co-axially mounted anode, the electrons emitted from the heated filament travel in substantially straight lines to the surface of the anode. Upon impressing a transverse magnetic field upon the electron path, the path of the electrons becomes curved, the degree of curvature depending upon the intensity of the transverse magnetic field. Thus, with a sufficiently strong transverse magnetic field, the electron path may be so bent that alternate anodes will shield the remaining anodes from the electron stream.

I have found that, by reducing the magnetic field in the space immediately surrounding the cathode to substantially zero, the electrons are permitted to attain such velocity that, upon entering the magnetic field, the effect thereof is not sufficient to cause the electrons to return to the cathode.

In operation, upon impressing a transverse magnetic field upon a portion of the electron path, the electronspass radially outwardly from the surface of the hot cathode until they enter the magnetic field, whereupon the path of the electron is curved to cause it to strike one of the groups of anode elements 3 and 4. Such a path may -be indicated by the dotted lines 18 of Fig. 1,

in which the electrons are caused to strike anodes 3. i

Upon a reversal of the magnetic field, the path of the electrons, upon entering the region of the magnetic field, is curved in the opposite direction to cause the electrons to impinge upon the opposite group of anode elements 4. This path is represented by the dotted lines 19 in Fig. 1.

Thus, it can be'seen that, with the phase of the magnetic fieldand plate-filament cur rent adjusted properly, the direction of the plate-filament current through the balance coil may be such as to establish and maintain an alternating current in the oscillatory circuit.

From the foregoing description, it will be observed that the advantage of my invention resides in the provision of an'oscillation-generator system in which the customary anode losses may be distributed among the plurality of anodes, thus permitting the construction of a high-power vacuum-tube device of relatively small dimensions. While I have shown only one embodiment of my invention, it is capable of various other modifications without departing from the spirit and scope of my invention. I desire, therefore, that only such limitations means for establishing an electrostatic field I between said cathode and said anodes, whereby a space current is created in said vessel, and means operatively associated with said oscillatory circuit for directing the space currenet alternately from one plurality of plate elements to the other.

2. An oscillation generator comprising an evacuated vessel. a plurality of plate elements electrically connected, a second plurality of plate elements electrically connected to one another and arranged to alternate with the plate elements of the first plurality, an oscillatory circuit including separate, serially-connected, inductance and capacitance devices and connecting one of said pluralities to the other, a cathode, and means for establishing an electrostatic field between said cathode and said anodes, whereby a space current is created in said vessel, certain of said serially connected devices being operatively associated with said evacuated vessel to modulate said space current.

3. An oscillation-generator system comprising an evacuated vessel, a plurality of plate elements connected in parallel relation, a second plurality of plate elements also connected in parallel relation, the plates in the two groups being arranged alternately, a cathode for supplying a space current thereto, a circuit including inductance, a second circuit including inductance and capacitance, both circuits being in parallel and shunted across said first and second plurality of plate elements, and means for producing an electrostatic field between said plate elements and said cathode.

4. In a vacuum-tube device, the combination with a plurality of juxtaposed plate elements, of a cathode for supplying a spacecurrent stream, means for connecting alternate plate elements in parallel in two groups, and means whereby said space-current stream may be selectively controlled to impinge upon predetermiend groups of said plate elements.

5. In a vacuum-tube device, the combination with a plurality of juxtaposed plate elements, of a source of electron emission, an oscillatory circuit and means included in said oscillatory circuit whereby said electron emission may be selectively controlled to impinge upon predetermined groups of sepa- Ill) rated plate elements to cause said vacuumtube device to function as an oscillation said electron source and means whereby said electron stream may be selectively con-' trolled to impinge successively upon predetermined groups of separated plate elements to cause said vacuum-tube device to function as an oscillation generator.

7. In a Vacuum-tube oscillation generator,

the combination with a source of electron emission, of a plurality of plate elements dis posed annularly thereabout, alternate plate elements being connected in parallel, means for producing'an electrostatic field between said electron source and said groups of parallel connected plate elements, an oscillatory circuit including capacitance and an inductor shunted across said groups of plateelements, said inductor being disposed to produce a magnetic field transverse to the electron paths and transverse to straight lines joining successive plateelements, and said field being of substantially zero value in a region closely adjacent to' said electron source and of a maximum value in the surrounding region, whereby said electron stream may be selectively controlled.

8. An electrontube device comprising an evacuated'container, a plurality of anodes and a cathode disposed within said evacuatcd container and means for producing a magnetic field near the anodes, saidv field being transverse to the plane containing said cathode and said plate elements,- and said means being so disposed that the magnetic field at the surface of the cathode is substantially less than in the region of said anodes.

upon the one or the other of saidinclined plates.

10. The combination with an electronemitting cathode, of a pair of plates for receiving an electron stream therefrom, one of said plates being dlsposed at an angle .with respect to a straight line connecting said plate with said cathode, and means for deflecting said electron stream to cause the same to impinge more directly uponfsaid inclined plate, the other plate being arranged in such position as to be shielded by said inclined plate when said stream is deflected 11, The combination with an electronemitting cathode, of a plurality of annularly disposed plates associated therewith, alternate plates being connected in parallel, and successive plates being inclined at opposite angles with respectto their respective radial lines, and means for deflecting said electron stream to cause the same to impinge more directly upon the one or the other of said groups of parallel-connected inclined plates.

12. The combination with an electronemitting cathode, of two groups of alternately disposed plates for receiving an electron stream therefrom, the plates of one of said groups being disposed at anangle with] respect to a straight line connecting said cathode with said plates respectively, and means for deflecting said electron stream to cause the same to impinge more directly upon the inclined plates of said last-mentioned group, the plates of the other group being arranged in such position as to be shielded by said inclined plates when said stream is deflected.

'13. The combination with. an electronemitting cathode, of two groups of alternately disposed plates for receiving an elecdirections with respect to a straight line connecting said cathode with said plates respectively, and means for deflecting said electron stream to cause the same to impinge more directly upon oneor the other of said groups of inclined plates, the plates being so arranged that the plates of one group are shielded by the'plates of the other group whensaid stream is deflected.

14; The combination with an electronemitting cathode, of a plurality of annularly disposed plates associated therewith, alternate plates being connected in parallel, and means, including an annular coil "parallel to the plane of said. plurality of annularlv disposed plates and a smaller concentric coil carrying current in the direction opposite to the current in said annular, coil, for alternately strengthening and weakening the space current flowing tolthe two groups o parallel-connected plates.

15. The combination with an electron- Inc emitting cathode, of a plurality of annularly .1

disposed plates associated therewith, alternate plates being connected in parallel, and

successive plates being inclined at opposite angles with respect to their respective radial lines, annular coil parallel to the plane of said plurality of annularly disposed plates and as smaller concentric coil carrying. current in the direction opposite to the current in said annular coil, for alternately strengthening and weakening the space current flowing to the two groups of parallel-con nected plates. 1

16. The combination with an electronand means. including an moving toward elements disposed latively weak near said ,electron source,

tron streamto cause 10 more directl upon ceiving an electron stream therefrom, said plates being so disposed that each protects at least a part I the protecting plate, a tuned oscillation circuit serially associated with said plates, and means "responsive to said oscillation circuit for deflecting said electhe same to impinge" the one or the other of said incline plates." v 1.7. In a vacuum-tube oscillation gener ator, the combination with a source, of electron emission,

annularly thereabout, alternate plate elements being connected in parallelfand succesive plates being inclined at opposite angles with respect to their re- 'spective radial lines,-a tuned oscillation circuit seriallyv associated with said plates, and means responsive to said osclillation circuit for producing a transverse magnetic field which is relatively strong in the annular, re'gionof said plate .elements and rewhereby said electron stream maybe alternately deflected to impinge more directly inclined plates. 7 g

18.- In a vacuum-tube oscillation generator, the combination with a source of electron emission, of a plurality of plate ele ments disposed annularly thereabout, alternate plate elements being connected in annular coilparallel, and successive plates being inclined at opposite angles with respect to their respective circuit shunted across said groups of parallel-connected plate elements, said circuit including an inductor and a co denser, a coil also shunted across s'ai plate elements, and means associated with said coil for causing an electrostatic field .between said plurality of plate elements and said cathode, said inductor comprising an parallel to the plane of said of the other from electrons nected plates.

of a plurality of plate 7 annulus.

upon the one 'or the other of said groups of corresponding members of the several radial lines, an oscillatory readers plurality of annularly disposed plates and I a smaller concentric coil carrying current in the direction opposite to thecurrent in said annular coil for alternately strengthening and weakening the space current flowing to the two 19. In a device of the class described, a

disk-sha ed evacuated vessel means for 5 v u producing a space current therein, and

means adjacent the faces thereof for producing a field therein for controlling said space current. i

' 20. In a space-current device, a plurality in pairs, each pair converging In a space-current device, a plurality of electrodes arranged in an annular row in pairs, each pair converging inwardly and; a source oi electrons Within the 22. In a space-current devicc, a plurality of electrodes arranged in an annular row in pairs, each'pair converging inwardly and a source of electrons within the annulus, correspondingfmembers of the several pairsbeing electrically-connected.

'23. Data space-current device, a plurality of electrodes arranged in an annular row in pairs, each a source of electrons Within the annulus, pairs being electrically connected, and meansv or directing the electrons against the faces of theelectrodes away from the other member a magnetic field pro-- gressive'ly' changing in intensity from the .lln testimony whereof, l have hereunto subsribed my name this 8th day of February, 1921.. l

groups of parallel-conof electrodes arranged in an annular row inwardly. v

pair converging inwardly,

middle toward the periphery of the cross-' section thereof. 1

nnwrs wana'rner-on-on;

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