US1684104A - Electron-discharge device - Google Patents

Description

Sept. 11, 1928. Y

Y A. MAVROGENIS ELECTRON mscmaen DEVICE 2 Sheets-Sheet 1 Filed Feb. 21. 1927 Sept. 11, 1928. I 1,684,104

A. MAVROGENIS ELECTRON DISCHARGE DEVICE Fil ed Feb..21. 1927 2 Sheets-Sheet 2 '54 a-ya? l U J/JJJv 527/3.

atented Sept. 11, 1928.

.ARISTOTE MAVBOGENIS, OF MILWAUKEE, WISCONSIN.

ELECTRON-DISCHARGE DEVICE.

Application filed February 21, 1927. Serial No. 169,876;

I This invention relates to unitary electron discharge, devices andis particularly directed to a device in which means are pro vided forv maintaining a permanent negative potential on the controlling element with respect ,to the cathode of such unitary devices.

It has been the practice heretofore to insert a relatively small dry battery or storage battery or its equivalent C battery eliminator in the grid circuit of a vacuum tube in order to maintain the grid at a suitable negative potential with respect to the cathode of such tubes when used as detectors or amplifiers.

In case of a vacuum tube amplifier when used at audio frequency with a relatively large ,output plate current, a C battery is inserted in the grid circuit between the grid and the cathode of such amplifier in order to maintain a permanent negative potential 2 of a suitable value on the grid, such poten- ,tial being atleast equal to the manimum amplitude of voltage variation of tll8 1I1 COIl 1- ing radio-waves impressed on the grid 1n order to secure distortionless, reception. Such vacuum tube amplifiers are usually of the audion type known under the trade name of power amplifiers, and are usuallyused in the last stage of the audio frequency amplification of the radio receiver. These tubes necessitate a G battery in the gr d circuit when their output plate current 15 equal to or above three to five milliamperes,

in orderto securedistortionless reception. The-tubes therefore require not only the usual filament and plate batteries, but also the additional C battery, or else their equivalent battery eliminatorsf It is a well-known fact that the addition to any radio receiver of a third auxiliary C- battery or its equivalent G battery eliminator not only increases the number of access" sories of such radio receiver, but also necessitates auxiliary busbar connections and binding posts'which thus produce an in- .v

' tube.

batteries, and to provide a unitary electron discharge device which not onl avoids th necessity of both filament and p ate batteries or their equivalent battery eliminators, but also eliminates the C battery or its equiva lent C battery eliminator.

A further object is to provide a permanent means within the unitary structure of thr electron discharge device for maintaining a permanent and suitable negative potential on the grid of the device.

Further objects are to provide means for impressing a permanent, suitable negative voltage on the controlling element of the un tary device by means which are perma nently associated with the unitary structure of the device, and which do not require either renewals, adjustments, upkeep expense, or any additional element within the This invention is particularly applicable to vacuum tubes of the general type disi closed in my prior Patents, N o. 1,570,4a4 of January 19,- 1926, for Wireless apparatus,

and for electron discharge devices, N o. 1,f338,499, of August 9,1927; No. 1,616 914, of February 8, 1927; No. 1,629,171 of May 11, 1927, and my copending applications for electron discharge devices, Serial No. 145,940, filed November 3, 1926; and Serial No. 159,313, filed Jan. 6, 1927.

Embodiments of the -invention are shown in the accompanying drawings in which Figure 1 is a diagrammatic view showmg one form of the invention and disclosin'r particulqrly a unitary electron discharge de v1ce hav ng a single wave rectifier; 5

Flgure 2 1s a view corresponding to Figure 1 showing the device adapted for double wave rectification;

Figure 3 is a perspective view part1 in section showing the physical structure of the tube, diagrammatically shown in Figure 2;

Figure/1 is a sectional View on the line 4 4: of Figure 3; Y, Y

Figure 5 is a diagrammatic view of a modified form of the invention; e t Figure 6 shows a modified form of the invention in which a vapor rectifier isemployed; i

in which a full wave vapor rectifier is used.

Referring to Figure 1, it will be seen that the device comprises a unitary structure whlch consists of an evacuated vessel 1 hav- V I Figure 7 shows a further modified .form 7 iio ing a base portion 2. The vessel 1 is preferably of the high vacuum type and encloses a rectifier, indicated generally by the reference character It, a current limiting device, indicated generally by the reference character C, and an audion, indicated generally by the reference character A. Within the base 2 of the device which constitutes a permanent portion of the struc- 'ture are mounted the condensers and resistance, as hereinafter described, so that the device may be inserted in a tube socket or removed therefrom as a unit.

The device is provided with four prongs v indicated at 3, 4, 5, and.6, which extend outwardly through the base of the. tube, al-

though for convenience of illustration, they have been shown diagrammatically in their most easily illustrated positions in Figure 1.

The rectifier has an equipotential cathode 7 .and an anode 8. The anode is connected directly to the prong 3 and from thence to one of the alternating current mains 9. The cathode is connected by means of the conductor 10 to the anode 11 of the current limiting device. The cathode 12 of the current limiting device is connected by means of the conductor 13 to one end of a resistance 14, as shown in Figure 1, to the upper end of such resistance. This upper end of the resistance is also connected to an auxiliary binding post 15 accessible externally of the tube, as described in detail in connection with Figures 3 and 4. At a suitable point along the resistance 14, the equipotential cathode 16 of the audion A is connected,

the plate 17 of the audion being connected through the translating device, such as the primary 18 of an inter-valve transformer to the point 15 and, consequently, to the upper side of the resistance 14. Consequently, the audion has impressed between its plate and cathode the voltage drop between thepoint at which the cathode is attached to the resistance 14' and the upper end of the resists ance or the point where the contact or binding post 15, is attached. I The grid 19 is interposed between the cathode 16 and the plate 17 and is connected to one end of the secondary 20 of the input transformer, the

other end of the secondary being connected to the prong 4. Further, it is to be noted that, this prong. is connected through a variable resistance 21 to the other main 22 of the alternating current supply system.

I It is to beln'ot'ed that a storage condenser 23 .is connected between the conductor 10 and the prong 4 and also it is to'be noted that the resistance 14 'isparalleled or bridged by means of the bypass condenser 24. Further, it will be noted from a considerationof Figure 1 that the resistance. 14 and the bypass condenser 24 are both in reality bridged around the audion.

It is to be noted further that the lower audion.

end of the resistance 14 is connected to the common point of the condensers 24 and 23.

It is to be noted further that filaments, as

indicated at 25, are provided for heating each of the eqnipotential cathodes 7,12,.and 16, and that these filaments are joined in series, although obviously they could be joined in parallel, if desired, and have their ends connected to the prongs 3 and 4. It is preferable to connect these filaments in series as it has been found more readily practicable to construct a filament so connected as to permit its direct connection to the volt alternating current mains.

It will be seen that current rectified by the rectifier R passes along conductors 10 to the plate 11 of the current limitingdevice. From thence, current passes to the cathode .12 of such device. Further, it is to be noted that the storage condenser 23 is connected to the conductor 10 and to the prong 4 and consequently stores up a part of the pulsations. The current limiting device, as illustrated in Figure 1 is of the thermionic type described in greater detail in my co-pending applications noted above, and in my prior patents. It is intended that it be saturated at the minimum voltage supplied by the pulsatingunidirectional current so that the cur rent flow through the device is absolutely constant, irrespective of any variation of voltage impressed thereon.

Current from this current limiting device passes through the resistance 14 to the prong 4 and from thence to the other main. Further, it is to be noted that the upper end of the resistance 14 is positive with respect to the point at which the cathode 16 is attached. sired for the audion may be obtained by selecting the point at which the cathode is connected, as it is to be noted that the plate is connected through the output device with the binding post 15.

It is to be particularly noted also that by adjusting the point at which the cathode 16 is connected to theresistance 14 that the exact negative potential desired upon the grid may be obtained) For example, the point at which the cathode is attached to the resistance 14 is positive with respect to the lower end of this resistance. end of the resistance 14 is connected through the prong 4 and through the input device 20 to the grid 19 and, consequently, the. grid is maintained permanently negative with respect to the cathode 16 of the It will be seen that the resistance 14 and the condensers 23 and 24 are permanently carried in the base of the unitary'device and that the device is provided with only four prongs and with anauxiliarybinding 'post hereinafter described in greater detail.

Further, fit will be seen that the device Consequently, the exact voltage de- The lower is so constructed that it eliminates not only the A battery and the B battery, but also the (3 battery, or the equivalent C battery without the addition of any extra element within the evacuated portion of the tube.

In the form of the invention shown in Figure 2, the same general inventive idea is followed. The device is provided with the prongs 26, 27, 28, and 29 and with the auxiliary' binding posts .30 and 31. -The filaments 32'are connectedin series and directly across the alternating current mains 9 and 22 through the variable resistance 21. In this form of the invention, the prongs 26 and 27 which are connected to the two mains are directly connected to the anodes 33 and 34 of afull. wave rectifier. Further, the prongs 26 and 27 are bridged by the resistance 35. The full wave rectifier is provided with an equipotential cathode 36 which is connected by means of the conductor 37 with the anode 38 of the current limiting device. Further, it is connected to one side of the storage condenser 39' The cathods 40 of the current limiting device is connected tothe anode or plate 41 of the audion and also to one side of the bypass condenser 42- and to the upper side of the resistance 43. The lower side of the resistance and the other sidesof the condensers 39 and 42 mentioned previously are connected by a common conductor 44 with the center point of the resistance 35. Y Further, it is to be noted that the binding post 31 is connected to an intermediate point of resistance 43, pref-' erably adjacent its lower end as 'indicated, and that the binding post 30 is.

connected to the. lower end of the resistance by means of the common conductor 44. The cathode 45 of the audion. is connected through the output device or translating device, indicated by the reference character-46, to the binding post 31 and consequently to the intermediate point of the resistance 43. The grid is connected through the prong 28 with one side of the input secondary 47, the other side of such secondary beingconnected to the] binding post-30, and consequently, to .the lower end of the resistance 43. It will be' seen, therefore, that the point at which the binding post 31 is connected to the resistance 43 and the point at which the-binding post 30 is connected to such resistance causes a negative potentialto be impressed on the grid of the audion and, consequently, such grid is maintained negative with respect to the cathode of the audion. The full wave rectifier, of course, rectifies both of the half waves of the alternating current and consequently, a smaller storage condenser 39 may .be used than-with the form previously described. Further, the resistance 35 provides a neutral point for the return conductor 44. In both forms of the; invention not only is the temperature of the filament controlled by the resistance 21, but also the voltage impressed on the audion is simultaneously controlled by such resistance. 7 In the physical embodiment of the invention disclosed diagrammatically in Figure 2, it will be seen particularly from F ig ures 3 and 4, that the tube base 2 of the unitary device carries the several prongs and also is provided with a pair of outwardly projecting members or lugs 48 which carry the binding posts 30 and 31. Further,

. the prongs 26,27, 28, and 29 project through the base 2 in the usual manner. The evacuated vessel 1 is provided with an upstanding bridge 49 which supports the several elements of the device. The particular form of cathode and filament used in this tube is illustrated particularl in detail in my Patent No. 1,629,171, of ay 17, 1927, for electron discharge devices.

Any suitable means may be provided for connecting the binding posts 30 and 31 with the respective conductors. For example, a brass or other metal sleeve 50 (see Figures 3 and 4) may be embedded in the arms 48 and may cont'act'with the screw of the binding posts 30 or 31. Preferably, the metal sleeve is hollow and the conductor 51 leading thereto may be readily soldered, as indicated at 52. It is also preferable to roughen the exterior of the sleeve 50 so that the insulating base portion 2 may readily grip such sleeve. It is to be distinctly understood, however, that other forms may be employed than. thefo'rms specified herewith without departing from the spirit of this invention. It is also to be understood that preferably the condensers 39 and 42, as well as the resistance 43 and 35, shown in Figure 2, are formed in a single block, as indicated at 53 in Figure 3', and that this block is mounted in the base portion 2 of the device. preferable also to separate the block from the tube by means of a mica or other insulating washer 54, as indicated in Figure 3.

With a tube constructed as illustrated, the usual type of tube socket may be employed into which the tubeis inserted, as only four prongsare used, the auxiliary connections being furnished by the binding posts 30 and It is preferable, however, to provide the auxiliary contacts in the form of auxiliary binding postsso that the device maybe insertedin standard sockets Without requir- It is v ii'iglany'alterations and may, consequently, utilize and cooperatewith standard equip- 1 ment.

Referring to the form of the invention shown in Figure 5, it will beseen that the device comprises the evacuated vessel 1 having the base 2. However, this vessel is divided into three compartments 55, 56, and 57. The compartment 55 contains a pair of relatively'small anodes 58 and a relatively large cathode 59 which encloses the anodes.

The compartment 55 contains a rarefied gas,

4 preferably of the helium group of such a pressure as to maintain a gaseous discharge between the electrodes 58 and 59. The cathode 59 is connected-by means of.a resistance 60 to the anode 61 of a voltage 1imiting device The anode 61 of this device is relatively small and the cathode 62 thereof ,is relatively large and preferably cylindrical andencloses the anode. The gas in the compartment 56 is also of the helium group and of such a pressure as to permit a gaseous dis arge between the electrodes. It

- is to be noted in this form of the invention i the resistance 63 through the resistance 60.

A storage condenser 65 is connected to the cathode 59 and also to the common conductor 64. A bypass condenser 66 is arranged parallel to the resistance 63. An intermediate point, preferably adjacent the lower end of the resistance 63 is connected to the cathode 67 of the audion, the plate 68 of the audion being connected through a translating or output device 68" back to the upper end of the resistance 63. This connection is through'one of the external binding postsg 68 similar to the binding posts 30 and 31,

previously described. The other binding nish a bypass aroundthe audion to take care post 69 is connected to the lower end of the resistance 63. Further, the bindingpost 69 whichleads to the lower end of the resistance 63 or to the, commonconductorl64 is connected through the input secondary 70 to the grid 71 of the audion. The audion,

.it will be noted, is contained in the separate compartment 57. Itwill be seen fromthe connections described that a negative potential is impressed upon the grid 71 of the audion or, in other words, the grid is maintained at a definite -predetermined potential with reference to the cathode 67 of the audion. Also, it is to be noted that the device in'the compartment whose anodes 58' are connected to the two supply mains 9 and 22 through the variable therefore,

sistance 72 adjusts not only the voltage of the rectifier, but also the temperature of the filamentand, consequently, the temperature of the equipotential cathode of the audion.

The metal selected-for the anodes 58 and '61- of the rectifier and voltage limiting device and forthe cathodes 59 and 62 of the rectifier and voltage limiting device may be of any suitable type. Preferably, however, the

cathodes at each of these two devices is coated with an oxide or compound of alkaline metals. I

It is tobe noted further that the voltage limiting device has a voltage current characteristic which has a substantial portion thereof parallel to the current axis whereby a relatively great changein current flow may occur through the apparatus without appreciably altering the voltage between its terminals. Consequently when the rectifier supplies pulsating uni and charges thestora e condenser 65, such condenser discharges through the resistance 60 across which a voltage drop occurs. The apparatus in the vessel 56 constitutes in efiect means for securing a constant difference in potential between the end of the resistance 60 and the common conductor 64 and, con sequently, a constant upon the audion. i The condenser 66 and resistance 63 furof any variations that may occur due to variations in the signals received by the audion and, consequently, variations in the demand made upon the apparatus. Referring to Figure 6, it will be seen that a further form of the invention has been shown in which a vapor rectifier is employed. By the expression, vapor rectifier, it is intended that either gaseous rectifiers or strictly vapor rectifiers be included.

directional current voltage isimpressed In this form of the invention, the rectifier comprises a vessel 74 of high heat resisting characteristics and of good dielectric properties and of non-porous material, such for instance as quartz, silica, glass, etc., and is hermetically sealed, An anode 75 is sealed in the upper portion of the vessel 74: and in' the lower bulb-like portion an electrode 76 is positioned. -The lower bulb-like portion preferably contains a cathode of relatively low melting point or else one which emits vapors at a relatively low temperature, such vapors being the ionizing agents in the rectifier. A pool of mercury may be used or else other materials, such' as alkali metals, for

. example, potassium, sodium, rubidium, caethe conductors to the electrodes 75 and 76 are relatively rigid so that they will act as supports for the rectifier.

The cathode is connected by means of the conductors 78 and 79 to the plate 80 of the current limiting device and to one side of the storage condenser 81. The other side of the storage condenser is connected by means of a conductor 82 through a variable resistance 83 to the other main'84.

The vessel of the rectifier has a central enlarg'ement 85 and two coatings 86 and 87 separated-by such enlargement. The coatings may be formed of electrically conduct- I ing and electroionically active material as described in my copending application, Serial No. 150,644, filed, November 26, 1926,. for gaseous discharge device; and Serial No. 159,313, filed January 6, 1927. v v

The current passes from the anode 80 to the cathode 86 of the thermionic current limiting device and passes from the cathode 86 through the conductor 88 to one side of the bypass condenser 89, and bypass resistance 90.

The other side of the condenser 89 and resistance 90 are connected to the conductor 82. From the conductor 88 current passes by way of conductor 91 to one side of a translating device, such as the primary 92 of a transformer. The other side of the primary is connected to the-plate. 93 of the audion, such audion having a grid 94 and the cathode 87 previously described. The cathode 87 is connected by means of the con ductor 95 to a point on the resistance 90" near its lower end. Further, it is to be noted that the grid 94 is connected through the secondary 96 of a transformer to the lower end of the resistance 90. In this manner, a negative potential isimpressed upon the grid and the grid is maintained negative with respect to the'cathode of. the audion. In the form shownin Figure 7 substam tially the same arrangement is followed except that the rectifier is a fullwave recti fier. Further, the cathodes 97 and 98 of the current limiting device and audion respectively, are shown as separate metal mem bers and are preferably coated with a ldw' electron aflinity oxide. Obviously, either form ofcathode, viz. the one previously described or the one just described, may be used on either the single or full wave'rectifier, without departing from the spirit of the invention. I

The rectifier vessel 99 has an electrode 100 sealed in its bulb-like lower end and a pair end. The anodes are connected to the mains 103 and 104 through a variable resistance 105. Preferably, a heating resistance 106 is of anodes 101 and 102 sealed in its upper connected across the conductors leading from the anodes 101 and 102 and further, a resistance 107 is bridged thereacross. The

center point of this resistance is connected to one side of the storage condenser 81 and bypasscondenser 89 and bypass resistance 90. The remaining connections are the same as those described for Figure 6.

This last form of the invention provides.

for full" rectification and obviously a smaller storage condenser may be employed. i

It will be seen that a novel form of unitary electron discharge device has been provided by this invention which is so constructed that itis adapted for energization wholly from alternating current mains and not onlysupplies energy for heating the several cathodes of the device and for furnishing current to the plate of the audion, but also furnishes the necessary difference of potential between the grid of the audion and the cathode ofthe audion, so that the apparatus may function at the most advantageous portion of its characteristic curve. In other words, this device insures distortionless reproduction and does not require any additional' C battery or any auxiliary apparatus whatsoever. Instead, the device is a com plete and self-contained unit and may be connected directly to-the input and output portions of the system. and may be directly supplied from commercial alternating cur rent mains.

Although the invention has been described in considerable. detail, such description is intended as illustrative rather than limiting as the invention may be variously embodied and as the scope of such invention is to be determined as claimed.

I claim: 1. A. unitary electron discharge device ineluding an evacuated vessel, an audion mounted within said vessel-and-having a plate a-Icathode-and an interposed grid, a rectifiermounted wlthin said vessel for supplying energy to said audion,'-means carried byand forming- 1a unitary portion of-said device for impressing a negatlve voltage on said grid wit reference to the cathode of,

said audion,- and means for smoothing out the pulsations in the energy supplied by said rectifier.

2. A unitary electron discharge device adapted to be energized from a source of alternating current including an audion having a plate, a cathode, and a. grid, a rectifier for supplying said audion, an energy controlling device for smoothing out the pulsations'of energy supplied said audion by said rectifier, and means for maintaining apredetermined volt-age difference between said grid and cathode, said audion, rectifier, and voltage maintaining means being permanently carried by and forming a unitary part of said electron discharge device.

3. unitary electron discharge device including anv evacuated vessel, an audion mounted'within said vessel and having a plate, a cathode and an interposed grid, a rectifier mounted within said vessel for supplying said audion, means for smoothing out the'pulsations of energy supplied by said rectifier, and a resistance bridged around said audion and having a portion thereof connected with the'grid of the audion for.

maintaining a definite predetermined voltage difierence between the grid and the cathode of said audion. v

4. A unitary electron discharge device including an evacuated vessel having a base permanently attached thereto and provided with terminals, an audion mounted within said evacuated vessel and having a cathode, a plate and an interposed grid, a rectifier mounted ,within said vessel for supplying said resistance being located in the said base,

and connections leading from said terminals to the electrodes of the audion, rectifier, and to said resistance.

In testimony that I claim the foregoing I have hereunto set my hand at Milwaukee, in the county of Milwaukee, and State of Wisconsin.

ARISTOTE MAVROGENIS.

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