US1923552A - Vacuum tube - Google Patents

Description

Aug. 22, 1933.

E. G. MLfRPHY VACUUM TUBE Filed Oct. 24, 1928 Patented Aug. 22, 1933 unirse s'rnrss PATsN f orifflci:N l

2 Claims.

The present invention relates to vacuum tubes being a special adaptation oi the method and means disclosed in my patent, Serial No. 1,699;- 011, dated January 15, 1929, for vacuum tube.

In the copending application above referred to, a general method or system was shown whereby the electrodes oi-a vacuum tube could be controlled and regulated simultaneously or individually and selectively, as desired, by the insertion of removable cartridge.' elements. The results achieved by this system are' accomplished by merely moving or exchanging the wiring leads in the base of the vacuum tubo from one cartridge element or electrode tol the other. Many external control devices and wiring are elminated by the method above indicated, 'while the greatly shortened leads to the electrode add also substantially to the efficiency ci tubes oi the design and construction herein `reierred to, the present modification oi which has for its object the provision oi a novel vacuum tube with self-inclosed means for varying or balancing the electrostatic capacity between the electrodes ofthe tube.

Another object isto provide a vacuum tube of the type indicated with insertable adjustable means for neutralizing or balancing the electrostatic capacity oi the said electrodes with the option of immediately restoring the tube to its conventional operation and function by 'the withdrawal of theinsertable means;

Additional objects and advantages ci' the method employed will appear more fully in the hereinafter described details when taken in connection with the accompanying drawing inwhich,

Figure l is a side elevation of the exterior of a vacuum tube embodying my invention;

Fig. 2 Vis a vertical sectionalY view talenvon line 2-2 of Fig. 1, with parts broken away;

Fig. 3 is a vertical section, similar to Fig. of a slightly modiied form of my invention;

Fig. 4 is an enlarged longitudinal vsection of the adjustable cartridge condenser which is to be inserted in the base of the tube;

Fig. 5 is an enlarged sectional view of the cartridge resistance element also insertable in the base of the tube;

Fig. 6 is an elevational View of a tube similar to that shown in Figs. 1 and 2, with thev addition of an insertable filament control cartridge resistance in the base, and

Fig. 7 is a vertical sectional view, taken on line 7--7 of Fig. 6, parts being broken away.

In thedrawing wherein similar characters (Cl. Z50-27.5)

of reference indicate corresponding parts in the several views ci the preferred forms of the in-V vention, A designates a vacuum tube having an envelope 10 secured to a base 11, the enevelope being formed integraiiy with Vthe glass press 12 60 in which latter are secured the supporting rod 13 for the lainent 1li; the supporting rod 15 for the grid 16, and the rod 17 which supports the anode or plate 18.

. To the bottom of the base 11 of the vacuum 65 tube Vare secured the circuit-completing prongs which include the filament prongs 19, 20; the grid prong 21 which `is connected to the grid by the conductrn` wire 22, and the anode prong 23 connectedto` the anode electrode by wire 24. By inspection of Figs. 2 and 3, it will be seen that grid connecting wire 22 is attached to one oi` the split clamping conductor elements 25, 26 which are formed of metal and suitably fastened in registering holes in the base 11, the anode 75 conductor wire being attached to element 26. The split clamping elements 25, 26 provide resilient gripping sockets for the reception of theV insertable cartridge condenser B which is formed of a tube of suitable dielectric 277-having ` metal plugs 28, 29 at the ends Vthereof in which ytheplates or rods 30, 31 are in'ibedded. Metal caps 32 33 communicating with the metal plugs 28,

29 provide a means whereby the cartridge con denser may be inserted in the metal clamping elements 25, 26. vThe cartridge condenser B has ametal sleeve 34 slidablecn the exterior of the dielectric` tube 27, the sleeve being engaged by an larm 35 secured to the bottom of theV base 11, whereby when-the ycondenser B is inserted in the. socket provided by the clamping elements 26, the arm 35, as shown in Fig.` 2, will contact with thesleeve 34 and shift samefto .thel right or left according to the direction in which Y the condenser is thrust,this being accom- 95 plished with any convenient object such as a match, nail, pen handle, etc., etc.

1n the slightly niodied 'form of the invention shown in Fig. 3, the disposition of the electrodes and the wiring therein is identical with that illustrated in Fig. 2, the only difference in the two forms shown being that in Fig. 3 the sleeve 34 has integrally depending rod 3a which is secured permanently tothe bottom oi the base 11 by small nuts 36 or in any suitable manner. 105 As in Fig. 2, the sleeve'Sa forms one of the plates ci the condenser B, the electrostatic capacity of which is varied by sliding the sleeve relatively to the inner plates or rods 30, 31.

The cartridge condenser B is slid to the right L10 or left through the fixed sleeve in the modication shown in Fig. 3. In Fig. 2, the sleeve 34,

plate electrodes, together with the wiring thereion-is practically the same as that shown in the tube illustrated in Fig. 2. In Figs. 6v and '7 however, an additional convenience is provided in the form of an insertable cartridgeresistanc'e C for the control of the lcathode yor filament 14. For the reception of this` cartridge resistance, a second pair of metal clamping elements 3.7, 38 are provided. The resistance C like the cartridge condenser B consists of the usual tube of dielectric 39 having'metal plugs 40, 41 connected by a small coil 42 of resistance wire. Metal capsx 43, 44 communicating with the metal plugs '40, 4l complete the element C which is also removably received between the clamping elements 37, 38.' l J In Figs. 2 and 3, the filament circuit is coinpleted from prong 19, through wire 19', 4rod 13,

Y. filament 14, conductor 14 to prong 20. In the tube shown in Figs 6 and 7, prongv 19 is connected by a wire 45 to clamping element 38 whence the current passes through metal cap 44, metal plug 41, resistance 42,-metal plug 40, metal cap clamping element 37, wire connected to rod 13, Vlament 14, wire 14 to prong 20. In the formv of tube Vlast mentioned, the electrostatic capacity of thegrid and plate` electrodes can be varied or neutralized, while the filament may be suitable energized without the aid of external control apparatus.

The function andoperation of the tubes illustrated anddescribed has been in large measure indicated rfrom the foregoing description, the

- inter-electrode capacity of the electrodes of these tubes being susceptible of variation and the inter-electrode capacity coupling, of vneutralization by thevmethod and means set forth. The tendency to `self-oscillation in circuits associated with the grid and anode electrodes of 'a thermionic valve, particularly circuits employing radio-frequency amplification and rcgeneration,is frequently an undesirable feature by reason of the distortionofthe signals received. The remarkable clearness of tone and general quietness of operation of radio receiving sets employing the so-called neutralization prinvciple is, of course, well known. It is most conveniently practical bythe present method and means to vary or neutralize the grid-plate electrostatic capacity of thermionic vacuum tubes without resorting to the use of external means in the associated circuits, as heretofore used. The method rnow shown may be employed in connection with any of the electrodes of the tubes besidesfthe usual grid-plate combination above referred to Vand illustrated, as will be readily understood. It is especially to be noted that the envelope-of this tube and the electrodes therein are of conventional pattern as manufactured by any of the factory methods now employed, and that if desired, these tubes may 'be used in their ordinary capacity at once by .merely thrusting out the cartridge condenser.

VAs pointed out `in the original system described in my Patent 1,699,011 alluded to above,

into the base of the tube the control elementsV heretofore' used externally in the circuits associated with the tube electrodes.

The present modication of my invention, as is apparent Vto those skilled in this art, is susceptible of considerable variation and modification, and I do not accordingly wish to be understood as conning myself to the precise details of construction set forth, save to the extent these are circumscribed within the scope of the appended claims.

What I claim as new and Letters Patent is:

vLA thermionic valve having a plurality of electrodes in an envelope, a base secured to. said envelope, av variable cartridge condenser insertably mounted in said base and having a makeand-break connection with two of said electrodes, and anr element in the base coacting with a sleeve slidably mounted` on said condenser whereby the capacity of the condenser and consequently the electrostatic capacity rof the two said electrodes may be varied.

2. A device of the character described comdesire to secure by prising a plurality rof electrodes in an envelope,

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