US2092770A - Radio circuit - Google Patents

Description

Sept 14, 1937.

A. MAVROGE'NIS RADIO CIRCUIT.

Original Filed May 17, 1929 2 Sheets-Sheet l Sm; nu;

Sept. 14, 1-937.- A. MAVROGENIS I 2,092,770

kAbI'o CIRCUIT Original Filed May 17, 1929 2 Sheets-Sheet 2 'vices having at leutaeathode, an

Patented Seph'14, i931 umri-zn "STAT-ES ,PATENT OFFICE ammo I uprocmcnrr Manama," ruinous. Wla, lim to Radio mltion at America, New York.

N. Y., a eorpw'ation or Delaware application 1'], 1m, Serial No. I pplleation larch 868,833. Divided and thin a 10, 1934, Still No. 715,018

"claims. .(ci. sac-s7 control grid. Inthefirst ,flfe'auxiliary'grid is used mainlyqto space charge surrounding the. filament or cathode by drawing electronsoutoithis'spaceasiast as they. are emitted from the filament o; cathode, thereby-obtaining a condition approximating saturatlon. Such device may be used in radio work as a detector, amplifier, current limiting device or other deviceofithis general In the second v ement, the auxiliary grid or electrode may be used in some particular cases,

it so desired, as an auxiliary anode, receiving electrons emitted from the main anode, which latter ment where the auxiliary grid is mounted be-. 40

trostatic field between the, min

is bombarded by electrons received from the main cathode. Under these conditions the device acts as a negative resistance and may be'used'as an amplifier, as a generator oi continuous high frequency oscillations, or as a modulator.-' In this case the auxiliary grid is usually maintained more positive or at a higher positive voltage main anode withrapectto the main cathode. I In the first 'arrangeinentwhere the auxiliary 3nd or electrode is mountedbetween thecathode and the main grid, and in the second arrangetween the control grid and the. anode, the voltage dlflerence between the cathode and the aux: iliary grid, in each instance, may be oi. any desired value with reference to the voltage diiierence between the anode and the cathode.

In the second arrangement, where the auxila capacity to reduce or counter balance-the elecanode and the control grid,-ithe field being due-to the interelectrodai capacity oi' the electron discharge device. I Such device, therefore, may be used iii radio work as an amplifier in which a higher voltage amplification may be secured under some conditions without the presence oi. oscillation.

These devices becomevery unstable in use and need close care and frequent adjustment inlorder" to maintain them in an operative condition. If it is attempted to energize the filament by alter d and the filament or cathode or between-the anode and the ary grid or electrode is located or mounted be tween the control grid and the anode, it acts in' other suitable element of the tube.

nating current it has been found that suchdevices are not capable of satisfactory operation-under any condition. They are so unstable that they immediately go into unduirable oscillations and tail wholly to operate in their desired capacity. The mt that the field produced in the tube is pulsatiflg orvariabie, due to the variation in electron emissive power of the filament with the alternating heating from the alternating current, it is apparent that a hum and a material unsettling of the conditionswill result. Further than this, the filament has a variable magnetic field about it which alternates in step with the current and, consequently, produces a further pronounced disturbance. In addition to these efi'ects, the filament does not have all portions at the same potential when alternating current is used and, consequently, a further varying and disturbing elect is produced. All of these conditions or efi'ects are superimposed or added, one to the other, so that a'hlghly unstable condition obtains and one which immediately throws the tube into undesirable oscillations so that it cannot operate in the capacity intended.

Objects oi this invention are to provide means whereby the defects mentioned above are eliminated and to provide a. device in which a cathode and anode and a plurality oi! interposed grids are employed, one oi these grids being a control grid, another oi these grids being a'screen grid adapted to be furnished with a constant potentialtrom an alternating current'source. 9

Another object of the invention is to 'provide means, in a screen grid tube, which means perml the use of alternating current for cathode heating purposes without any disturbing efiect on the screening element or grid.

A further object of the invention is to provide means, in a screen grid tube, which means elec-' tro'magnetically 6r electrostatically shields or screens the screen grid from the cathode heatingmeans. x

Another object of the invention is to provide a screen grid tube an additional outer grid-like screening member, which may be connected with the screen grid proper or with any Another objectoi the invention is to provide a screen'grid tube in which the screening grid or grid-like element is connected to the cathode or other element or electrode of the tube.

Further objects are to provide an electron discharge device having a cathode,- a plurality of electrically, dissimilarelectrodes, one 01' which acts as a'screen electrode, and an anode-,in which either or both the screen electrode and the oathodeare adapted to be supplied from alternating current source, although .no unstable condition obtains. I

member of a tube from an alternatingcurrent source, such means beinglocated "either outside or inside the tube. j

Another object of the invention is to provide different potentialsfor the screen gridand the anode of the tube.

A further object of the invention'is to provide a screen grid tube suitable for either alternating or direct current operation.

A further objectof the invention is to provide appropriate circuits, as well as means for energizing a screen grid tube from either an altemating or direct current source.

A further object of the invention is to provide radio circuits and means for supplying one or more electrodes or elements of a screen grid tube from a source of current through a rectifier having-a cathode which may be a directly heatable filament or an indirectly heated element, or both.

Another object of the invention is to provide a screen grid tube having an outer screening or shielding member or element which may be substantially, mechanically separate and distinct from the inside of the wall of the receptacle or envelope of such tube.

Further objects are to provide a device of the character outlined above, which is provided with areduced number of terminals, although a plurality of electrically, dissimilar grids, elements or members are provided, which is extremely stable in operation and in which the cathode activating means is itself to be energized fr m a t rnatin current.

Further objects are to provide an electron dis-' charge device including rectifying and signal re- I sponsive means in which one or more of the parts are energized frorn'alternating current, in which there is no hum or other disturbance present, in which a screen or-shield grid is provided and maintained at a ed potential, which is positive with respect to the cathode oi the device.

A further object of the invention is to provide an electron discharge device having an equipotential -or. indirectly heated cathode, cathode heating means or a heater therefor, an anode and two interposed electrodes, one of which is an electron controlling electrode, and the other of which is a screen electrode.

Another object of the invention circuit connections including power supply means for energizing one or more of the elements of an electron discharge device provided with a. screen grid, such, for instance, as has been outlined immediately above. r

Further objects of the invention will appear as the description proceeds.

The present case is a division of my earlier application Serial No. 363,833, filed May 17, 1929.

Embodiments of the invention are shown in the accompanying drawings, in which:

Figure 1 is a diagrammatic viewshowing one form of the invention.

Figure 2 is a similar view, showing a further form of the invention.

Figure 3 is a view showing the invention.

Figure 4 is a diagrammatic view showing a fomi of the invention in which the cathode of the. signal responsive device has a double is to provide 3 a further form of dutyand acts not only as anode for the rectifier. H w

Figure 5 is a view showing a form; otthe invention, in which the rectifier is'moun'ted within the vessel or envelope enclosing the signal responsive Figure -7 is a modified form of the invention,

somewhat similar to Figure 4, but showing a different arrangement of the elements. Figure 8 is a view, somewhat simila 7, showing a further form.

Referring to the drawings, particularly Fig ure 1, it will be seen that an evacuated vessel or envelope i encloses an equipotential or indirectly heated cathode '2, an anode 3, a control grid 4 and a screen grid 5. The screen grid is interposed between the control grid and the. anode and may, if desired, have a portion located beyond the anode in order to shield the anode from the control grid 4 as well as from possible external disturbances. The equipotential or indirectly heated cathode is heated in-any desired manner as by means of the filament 6.

A rectifier i is provided with an anode a cathode 9. The rectifier is supplied from an alternating current source as, forinstance, by means of the secondary I0 of a transformer. The cathode of the reotifierisconheoted through smoothing means, including a choke coil ii and sand a cathode, but @155; as in to Figure condensers i2 and I3, to-one ehdof a resistance Id, The other end of the resistance is connected to the negative side of the condensers i2 and I3 and to the equipotential or indirectly heated cathode 2. The positive sides of the condensers are connected .to opposite ends of the choke a portionof the resistance id to the output coil i 5 as it is clear, as indicated in Figure 1 that the lower point 'of the coil or primary is may be connected to a selected point of the resistance M. Further, it is obvious that a resistance sired.

The screen grid 5 may have any desired voltage impressed thereon by-connecting it to a selected point of the resistance M, as shown in Figure 1. It is obvious, also, that the screen grid can be connected through a series resistance 'to the smoothing means, or both through a parmay be placed in series with the anode, if deallel resistance and a series resistance as shown I in Figure 6, hereinafter described.

In the form of the invention shown in Figure 1, separate secondaries l6 and it are provided for the filaments 6 and 9 of the signal responsive device and of the rectifier, respectively.

Referring to Figure 1, as well as to other figures of the drawings hereafter described, it will be seen that the anode 3, as shown diagrammatically, is enclosed or surrounded by the electrostatic shielding or screening means 5 and 5'. ,In other words, this anode 3 may be located, as showndiagrammatically, between a plurality of screening or shielding portions, members or elements which may be similar or dissimilar in structure,

and which'are placed opposite .to a plurality or surfaces or sides of the anode 3 and spaced therefrom. Therefore these'shielding or screening means are adapted to substantially intercept the inner and outer sides or surfaces or the anode and some oneor more of the elements of the device such as the control electrode or grid 4, whereby the-capacity between the anode 3 and the control electrode 4 or the capacitive coupling thereof is materially reduced or practi- 1 down to'the potential of the cathode, as a variand the screen grid I.

cally obviated. v

Referring again to Figure l, as'well as to other figures hereinafter described, it will beseen that a plurality of means, givenfor illustrative purposes, are provided in the system which enable the screen grid of the tube to be supplied at any suitable positive potential varying from that supplied to the anode or to the'anode circuit able connectionhas been illustrated. Obviously, difierent types of screen grid tubes, require different voltages for the screen grid, but this invention provides any desired voltage for the needs of any particular type of 'tube to thereby secure the maximum efiiciency.'

The input circuit may take any form desired, for instance, as shown in Figure 1, the secondary ll of theinput transformer may be connected at opposite ends to the equipotential or indirectly heated cathode! and the electron control grid 4. It isto be noted. also from reference to Figure 1 that the equipotential or indirectly heated cathode is connected to one end of the secondary 10 of the transformer, the other end of such secondary being connected to the anode 8 of the rectifier. 1 It. is to ,be appreciated that the smoothing means may be enclosed within the base of the tube, if desired, or maybe entirely separate therefrom without departing from the spirit of this invention.

From the description of the first form of the invention, it is apparent that the defects heretofore existing .in screen grid tubes,- which pre- 'clude their use when the parts are energized from alternating current, are entirely eliminated by this invention. For example, the electrostatic disturbance between the filament and the anode of the screen grid tube is wholly eliminated as the voltage difference between the anode and the equipotential or indirectly heated cathode does not fluctuate with the alternating heating current. A second defect, which exists with the former types of screen tubes, is eliminated by this invention, as the alternating electromagnetic field produced by the alternating current flowing in the filament does not manifest itself in the space outside the cathode. .Instead, the equipotential or indirectly heated cathode prevents any disturbln'g effect from being produced by this electromagnetic field.

Referring to Figure l, for example, it will immediately be seen that the electron-emitting element 2 is interposed between the heater I By this arran ement the element or cathode 2 is well adapted to substantially electrostatically or electromagnetically screen or shield the heater 0 from the screen grid. It is obvious that this arrangement permits the utilization of a variable or alternating current for producing the electronic emission required for the operation of the device without any appreciable disturbing eil'ectonthe operating characteristics of the vacuum tube.

A further defect existing in screen grid tubes,

' as heretofore constructed. is-overcome by this invention. In the screen grid tubes asheretofore made, a very unstable condition existed which precluded the use of the een grid tubes with alternating current. It be appreciated immediately that the great amplification secured by screen grid tubes has the inherent tendency to produce undesirable oscillations unless conditions are maintained stable within the tube. Obviously, when the filaments of screen grid tubes, as heretofore constructed, were energized by alternating current, a wholly inoperative arrangement resulted, as the different portions of the filament had diflerent voltages and, consequently, an unsettling condition was produced which immediately unbalanced the tube and threw this system into undesirable oscillation, thus rendering it impractical. In addition to this, the electron emissive power of the filament fluctuated,

with -eac'h fluctuation, of the current thus producing a further unstable effect.

With this invention, the great amplification secured by screen grid tubes is made possible even when the tube is energized from an'alternating current source. This-has not heretofore been possible, but due to the fact that the conditions within the tube, that is to say, the electrostatic and the electromagnetic fields are not allowed to manifest themselves in the space outside the cathode, nor 'is there any fluctuation whatsoever in the voltage at different points in the equipotential or indirectly heated cathode, but instead, a uniform voltage diiference is maintained between the anode and the cathode so that the maximum stability is obtained thereby, permitting the-adjustment for large ampliflcatlonwith the certainty of a stable operation of the device.

The invention may take other forms, for example, as shown in Figure 2, the smoothing means may be placed within tube. The evacuated portion i may enclose the same parts as those described in connection with Figure 1. Further, the smoothing means may consist of a condenser i9 bridged by a resistance 20. The tube is supplied by means of a rectifier Lsimilar to that previously described. The equipotential or indirectly heated cathode I of the signal responsive device may be connected to one of the leads from the filament 6 and this lead may be connected both to the secondaries l6 and iii. The input and output circuits are indicated as in Figure l. The screen grid 5 is connected to an intermediate point, or selected point, of the resistance 20.

In fact, means are provided for maintaining the screen grid 5 as well as the outer screen member I at any suitable potential.

Referring again to Figure 2, it will'be seen that the grid-like element interposed between the control grid 4 and the anode I or the screen grid I is electrically connected within the vacuum tube itself to other elements of the device such as to the cathode 2 and to the filament 8. Further, in the form shown, the outer shielding or screening portion or member I to the cathode I and to the filament I within the envelope of-the device, whereby it is adapted to be maintained in operation at substantially constant potential. Furthermore. this form of vachum tube requires a less number of tube termithe base l' 'of the is electrically connected nals than the form of device shown in Figure 1, j

for example.

It is obvious that either form, or in fact other forms, of smoothing Figure ,2, is located within the base i' of the tube, although obviously it might be located outside, if desired. The smoothing means is similarto that described in connection with Figure 2. However; the screen grid 2! is located between the control grid tial in the form shown. Otherwise; this form of the invention is similar to that shglwri in Figure 2.

Referrin'gE again to Figure 3, as well as to Figure 14, hereinafter described, it will be seen that "the grid-like element, or the space charge grid, or the screen grid 2| interposed between the cathode envelope of the vacuum tube, whereby this eleand the control electrode" or grid '22 is electrically connected to the cathode 2, as well as to the fila-.

ment 8 inthe form shown in Figure 3, within the ment or grid 2| is adapted to be maintained in operation, at substantiaily constant or fixed o;

tential. Further, the gridlike element or screen grid 2i which is shown located between the con- .trol grid 22 and the cathode 2 and which is thereby enabled to modify the electronic or'electrostatic I field between the cathode and this control grid or the anode 3, is adapted to be maintained at any suitable potential within the range extending from that supplied from the rectifier or power' supply'means down to the lowest potential of the cathode or of the power supply means as clearly shown in Figure 3 and Figure 4 by the conven tional'variable or adjustable connection given for illustrative purposes; whereby this gridlike element 2i is adapted to suit any particular condi tion.

In the form of the invention shown in Figure,

1, the screen grid has been shown as arranged in vFigure 3 and previously described, although obviously it could be arranged as shown in Figures 7 ever; diflfers from that previously described in 1 and2. The invention shown in Figure 4, howthat the equipotential or indirectly heated cathode 2 serves-as the anode of a rectifier, the oathode of such rectifier being the filament 6;. The smoothing means in this form of the invention may be similar to any of the forms previously described, or it may consist of a resistance 23 and condensers and 2 5, the condenser having in each instance one end connected toan end of the resistance 23. The resistance 23 takes the place; of the choke coil H, as illustrated in Figure 1.

Otherwise, the smoothing means functions in the same manner as that previously described and it inFigure 1.

may be located eithervinside the structure of the device-as shown in Figure 4, or outside as shown The tube may be energized ffo'm an alternating current source, for instance, from a single secondary 26. A portion of the secondary is employed for energizing the filament and a portion for supplying current to the anode and the screen grid.

It is to be noted, however, that other arrangements or secondaries could be employed, if desired, without departing from the spirit of this invention.

It is to be noted in this form of the invention that the anode of the signal responsive means or signal responsive portion is supplied with energy from the, rectifying portion or rectifier consisting of the filament 6 and the'catho'de 2 (which iunctions as the anode of 'the rectifier), the current, v

ofcourse, passing through the smoothing means. In the form of the inventidn shown in Figure 5, the same general type of signal responsive means 22 and the cathode 2 and it is adapted to be maintained at any'suitable poten:

has been shown as that previously described in connection withjlgure l. However, the rectifier in this form' of :the invention is mounted within the evacuated-portion of the tube. Freferablythe rectifier consists of an equipotential or indirectlyv and an anode 28. ,The device is supplied from an I heated cathode 21, a heater or filament 28 therefor alternating current source, ior instance, from the secondary of a transformer. One end of this secondary maybe connected to the anode 29 of the rectifier. .The cathode of the rectifier is connected to the smoothing means consisting of the condenser 82 bridged around a resistance 3|. The cathode'oi the rectifier is' connected to one end of the primary I! of the output circuit, the other end of such primary being connected to the anode 3 of the signal responsive means. The eq'uipotential or indirectly heated cathode 2 of'th'e' signal responsivemeans is'connected to one side of the filament 6. The filaments 6 and 28 may, if desired, be connected .inseries and may be energized from the secondary 30 of the transformer.

Referring again to Figure 5, as well as to Figure 1,, Figure 2 and to other figures hereinafter described, it will be immediately seen that the grid-like element, "or screen electrode 5, which is shown located between the anode 3 and the control grid I and which serves to modify the electronic or electrostatic field surrounding the said control grid or extending between this anode and said control grid, in other words to substantially intercept the lines of electron fiow or the elecof this device or to 'this anode 8, down tov the lowest potential or the cathode or of the power supply means, as clearly shown by the conventional variable or adjustable connection given t for illustrative purposesgwhereby this grid-like element is adapted to suit any particular condition. Further, in connection with Figure 5 as well as Figure 2 and ,otherflg'ul'eshereinafter described, this grid-like element or electrode 5 is the cathode ii, which is a part or a'point in this device of a substantially fixed or constant poten tial, whereby this grid-likeelement or screen electrode 5 is adapted to be maintained, in operation, at substantially fixed or constant potential. Furthermore, thisarrangement of the'cooperating elements or electrodesof this device makes it possible to provide a vacuum tube having areduced number of terminals or prongs.

In the forms of the invention shown and described, it is intended that the alternating current source be construed as any alternating current source. For instance, this alternating current source may be either directly from the mains, as will be described hereinaftea}? or may be from a secondary or a transformer connected with the supply mains. It is intended primarily that thes devices be energized from alternating.

current industrial supply mains when theuse of storage or drybatteries or accumulators is not maybe either directly electrically connected within the device itselfto' 'and, consequently,- to the other main.

the mains may be connected through a rheostat 34 to the smoothing means and to one side of the filaments 3 and 23, the other side of the filaments being connected to the anode 29 of therectifier The smoothing means or filter may take any form. for instance, it may have a resistance 35 associated with condensers 36 and 31, as previously described. The indirectly heated cathode 21 of the rectifier, is connected to one side of the smoothing means and-the smoothing means is connected to the anode 3 of the signal responsive device. A resistance 38 is bridged around the smoothing means and a selected point thereof is connected to the screen grid 5. The input circuit may include the secondary ii of the input transformer, whose ends are connected to the equipctential or indirectly heated cathode 2 of the signal responsive device and to the control grid. The

cathode 2 01 the signal responsive device is con-.

. rent or direct current such as the city mains 33.

Also, as shown in Fig. 6, the filament or cathode heating means 28 of the rectifier and the filament or heater 6 of the screen grid device are.

arranged in the same circuit with the resistance 34 and suppliedin series from the alternating or;

direct current mains 33. v

In the form of the invention shown in- Figure 7, the cathode 2 of the signal responsive device densers 40 and 4 I. I aroundthe smoothing means and an intermediate performs a double duty, as it acts not only as cathode for the signal responsive device, but also as the anode of the rectifier, the cathode of the rectifier being the filament 6. This construction, as thus far described, is similar to that shown in Figure 4. The smoothing means may be located in a. tube base adaptor as indicated in dotted line by the reference character 38 or it may be located in any position desired. The smoothing means may take any form, for example, it may consist of a choke coil 39 and con- A resistance 42 is bridged point thereof is connected to the screen grid 5. In this form of the invention the screen grid has been shown in a position similar to that described in Figure 1, although obviously it may be located in a position similar to that shown in Figures 3 and 4, depending, of course, upon the characteristics desired.

A somewhat similar arrangement is shown in Figure 8, in which the cathode 2 of the signal responsive means also acts as the anode of the rectifier, the cathode of the rectifier being the filament 6. The smoothing means in this form of the invention may be located either in the base of the tube or outside of the tube at any position desired.

Obviously, the smoothing means may take any form, for instance, it may consist of a condenser 43 bridged by a resistance 44, an intermediate point of which is connected to the screen grid I.

The device, similar to'thatshown in Figure .7, may be supplied from the secondary 43 Matransformer, a similar arrangement being shown inl 'igure'l. Thefilarnent'linFigures'l and'8 ,may be supplied from a portionoi the secondary 15 Further, it is apparent that the mm 5 shown in the different figures of the drawings .are to be considered as interchangeable, or in.

other words, a feature or.features shown in one figure may beused in the form of the invention shown in other figures, in accordance with the usual practice in interpreting the disclosures of an invention. Obviously, it is not necessary that all the elements 'or features shown in the various flguresshould be present in every instance. For example, the smoothing means shown at I 9 in Fig. 2 may be interchanged with the smoothing means II, II, and ll of Fig. 1; the smoothing means ll-l3 of- Fig. 1 may be contained in a vessel as shown in Fig. 7; the form of screen grid shown at 21 in Figs. 3 and 4 may be changed to the form shown in Figs. 1 and 2, or vice-versa, if so desired. Similar remarks apply to the remaining figures, and therefore the invention is not to be limited to what is specifically illustrated but only by the appended claims.

It is to be understood that the equipotential or indirectly heated cathodes in all forms of the invention are preferably coated or otherwise associated, with a thermionic oxide so that they will eniit electrons at a relatively low temperature', although, obviously, the spirit of the invention will not be departed from if plain uncoated equipotential 'or indirectly heated cathodes are employed. v

It is tobe noted, also, that the alternating current source in each instance is intended 'primarily to be the industrial alternating current supply mains, whether connected to the tube through a transformer orany other device or whether connected directly to the tube. It will be noted that provision has been made in this inoi all batteries if so desired and that the entire device may be .energized from alternating current with the assurance that a stable, satisfactory operate also with direct or fluctuating current as well as with alternating current, and that at least certain forms of the tube per se, outlined above, are adapted to operate with alternating current, as well as with direct current.

By the use of this invention it is possible to utilize thehigh amplification power of screen grid tubes and energize these tubes with alternating current, which prior to this invention has never before been possible, as the unstable and unsettling conditions noted above have always heretofore been present. This invention, however, eliminates or overcomes all of these unstable or unsettling conditions and insures, as stated, a smooth, uniform, stable and reliable operation of the device.

Although the equipotential or indirectly heated cathode has been shown as a cap-like member in the'diagrammatic showing, it may take any form desired.

Thetube outlined in this invention may be used as a radio frequency or audio frequency amplifier. or as a detector, and may be used in wireless work or in telephony.

llt is'to be that the 'vention for a complete and entire elimination 40 ed'to said source, and filter means between said 7 screen grid may take any form desired, for ex- Y ample, it may be formed of wire mesh,-a helix.

or .an apertured member. However, when a screen grid is employed having-a portion located outsideof; or beyond, the anode of the signal responsive 'device, this portion may. take any form,"as outlined above, or it may be formed of sheet metal in the form of a cylinder or any other shape. The anode, as well as the control grid, may surroundthe cathode, while the screen grid or grid-like electrode may surround the control grid'as one possible physical form of the invention. v

. It is to be clearly understood, that thedraw- V 5 ings disclose only a few embodiments of the invention, given'merely for illustrative purposes,-

' that the invention may be variously embodied,

that, obviously, the shape and'sizes of the different elements or parts, the location of the leads,

an the number of elements supplied from the same power source, and other features may be varied to suit any particular demand, and that various changes or modifications both in the devicev and in the circuits therefor are contemplated and are 25 to be considered as being within the scope and spirit .of the appended claims.

The expression conductively connected, as

used in cerain of the claimsgmeana-a connection capable of passing'direct current. 30 I claim:-

1. In a radio circuit,- the combination comprising anelectron discharge device including a filament, an anode, a control electrode and a screen grid, a sourceof alternating current, recti- 3 5 f ying-means having an indirectly heated cathode and cathode heating means. for supplying electricity at least to said screen grid and conductively connected to said source, means for supplying heating-alternating current to said filament and said cathode heating'means conductively connect:-

rectifyingmeans and said discharge device for smoothing out pulsations in the electricity sup-'- plied to said screen: grid. 5' 2. In a radio circuit, the combination comprising a multi-electrode electron discharge device including an indirectly heated cathode, an anode, a control grid, a screen grid and cathodeheating means, a source of alternating current, rectifying cathode heating means conductively connected to said source, and a filter between'said rectifying means and said discharge device for smoothing out pulsations in the electricity supplied' at least to said screen grid from said source.

3. In a radio circuit, the combination comindirectly heated cathode, an anode; a control electrode, a screening grid andcathode heating 1 means,'a source of alternating current, rectifying 7 ing an indirectly heated cathode, cathode heating grid.

means having indirectly heated cathode andanode electrodes and cathode heating means and conductively connected to said source," means for'. supplying heating alternating current to all saidprising an electron discharge device-including an means, a screen grid and a plurality of other electrodes, a sourceoi alternating current,-rectifying means having indirectly heated cathode and anode electrodes and cathode heating means for supplying electricity to at least said screen grid from said source, means including a resistance for supplying heating current to all said cathode heating means from said source, and operating electricity smoothing means connected to said rectifying means for smoothing out pulsations in theelectricity supplied at least to said screen 5. In a radio heated cathode, cathode heater means a screen grid and a plurality of other elements, a. source of alternating current, rectifying means having heatable filament and anode elements for supplying potential at least to said screen grid from said source, a circuit including said heater'means circuit, the combination of an electron discharge device having an indirectly and said filament adapted to be energized by alternating current from-said source,.a filter connected tosaidrectifying means, and connecting means from the said'fllter to said discharge device whereby a; substantially steady potential is supplied to said screen grid from said source.

6. In a radio circuit, the. combination of a 'multi-electr'ode electron discharge device including a cathode, an" anode, a control electrode and a screen grid positioned between said control electrode. and said anode, rectifying means havingheatable filament and anode elements, means whereby said cathode may be energized by direct or alternating current, smoothing means connected to said rectifying means and to said discharge device, and means whereby said screen grid maybe energized at asubstantially steady 7. In a radio circuit for operation from a source of either direct or alternating current, an electron discharge tube adaptedto serve both as operating current rectifying means and as signal responsive means and including a cathode, a screen grid and a plurality of other elements; means wherebyv said cathode may be energized by direct or alternating current; and means forimpressing a substantially potential from a source of either direct or 'alternating current.

steady voltage at least on said screen grid with,

reference to said cathode from said source.

8. In a radio circuit, .the combination of el tron discharge tube adapted to serve both as sign lresponsive means and as rectifying means and including. a cathode, an anode, a control grid and a screeninggrid, said grids being positioned between said" anode and said cathode, means whereby said cathode may be activated by direct or alternating current, and means whereby said device is supplied with space current from a source of either direct or alternating current.

9. In a radio circuit, the-combination of an electron discharge tube adaptedto serve both as;

signal responsive means and as operating current v rectifying means and having an indirectly heated cathode, cathode heating means, an anode, a I control grid anda screening grid positioned between said anode and said control grid, means whereby said cathode heating means may be energizedi by direct or alternating current, and cir cult connections whereby at least said screening grid is supplied with a positive potential from a source of either direct or alternating current.

10. In a radio circuit, the combination of'a thermionic tube adapted to serve bothas signal responsive means and as operating current rectifying means and'including an indirectly heatcontrol electrode and a grid-like electrode located betweeri said control electrode and said anode, a circuit including said heater means adapted to 5- be energized by direct or alternating current, and

means whereby said grid-like electrode is supplied with a substantially steady potential from a source of either-direct or alternating current.

11. In a radio circuit, the combination of an 10 electron discharge tube adapted to serve both as 25 emitting cathodes, aiplurality or anodes, a consignal responsive means and as operating current rectifying means and'including an indirectly heated cathode, cathode heater means, an

anode, a control electrode and a screening ele-v 1 ment, a circuit including said heater means and' a resistance adapted to be energized by direct or alternating current, and means. whereby at least said screening element is supplied with a substantially constant potential from a source ofeither direct or alternating current.

12. In a radio circuit, the combination of a thermionic tube serving both as -operating cu'rrent rectifying means andas signal responsive means and including a plurality of electron trol grid and an inner grid-like element located between one of said anodes and one of said oathodes, means whereby at least one of said cathodes may be activated by direct or alternating 30 current, and means whereby at least said inner thermionic tube comprising operating current grid-like element is supplied with a substantially steady potential from a source of either direct or alternating current. 1 13. In a radio circuit, the combination a rectifying means and signal responsive means including a heatable filament, an anode, an indirectly heated cathode, a second-anode, a control grid and a screening element, means where- 0 by said indirectly heated cathode may be activated by. direct or alternating current, and means whereby said screening element is supplied with a substantially constant potential from a source of either direct or alternating 5 current.

14. .In a radio circuit, the combination of a' ode, a control grid, a second anode and a screening element, means whereby at least said second cathode may be activated by direct or alternating current, and means whereby at least said screening element is supplied with a substantialor alternating, current.

. 15,-In a'radio circuit, the combination of a thermionic tube comprising rectifying and signal responsive means including a cathode, 'an

anode, a second cathode, a second anode, a conelement from a source 0! either direct or alter-' nating current.

0 16. In a radio circuit, the combination or a' thermionic tube comprising operating current rectii'ying means and signal responsive means including an indirectly heated cathode, an-

be supplied thereto.

anode. a second indirectly heated cathode, a sec- 0nd anode, a control grid, a screening grid positioned between said second anode and said second cathode and cathode heating means, a circuit including said cathode heating means adapted to be energized by direct or alternating current, filter means adapted to be supplied through said rectifying means, and connecting means from said filter means to said signal responsive means whereby said screening grid is supplied with a positive potential from a source of either direct or alternating current.

1'1. In a radio circuit, the combination oi! a thermionic tube having; operating current rectiiying means and signal responsive means including a cathode, an anode, a second cathode; a second anode, a control electrode, a screening grid positioned between said second anode and said control electrode and cathode heater means,

. a circuit including said cathode heater means adapted to be energized by-direct or alternating current, a filter for smoothing out pulsations in the electricity supplied to at least said screening -.grid, connecting means for said screening grid,

and connecting means for said rectifying means whereby either director alternating current may 18. In a radio circuit, a plurality of thermionic devices each having an anode, a cathode and a heater filament, one 01' said thermionic 'devices having also a control grid and a screening grid, a power supply line leading to the first of said thermionic devices, a conductive connection between the cathode oi. the firstthermionic device and the said screening grid of the second thermionlc device and including in series therewith an impedance, a second power line, a condenser bridged from the last mentioned connection to 's'creeningelectrode, a power supply line leading to the first of said thermionic devices. a conduc- .tive connection between the cathode of the first thermionic device and the screening electrode 01' the second thermionic device and including in series therewith an impedance, a second power line, a condenser bridged from the last men-a tioned connection to the second power line and ly steady potential from a source of either direct connected to said last mentioned connection on a side of said impedance, and a series circuit including the said heater elements and a resistance connected across. said power lines. 20. In a radio circuit, the combination of an electron discharge device having a cathode, an

ment, means whereby said cathode can be activated by direct or alternating current, means .i'or supplying said anode and said screening eleanode, a control electrode and a screening ele-

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