US2481456A - Electrical alternating currents amplifier - Google Patents

Description

Sept. 6, 1949. H. J. TYZZER ELECTRICAL ALTE IRNATING CURRENTS AMPLIFIER Filed March '9, 1945 v FIG. I

SECTION X X F'IG.2

INVENTOR HOWARD J. TYZZER BY M ATTORNE Patented Sept. 6, 1949 ELECTRICAL nprsnngrma cnmnrs AMPLIFIER Howard J. T'yzzer, Mountain- Lakes, K. J., assignor' to Ferris Instrument Nematodes; Boonton, N'.. it, a corporation oi New Jersey Application March. 9, 1945, SeriaLHo, 581,865

2 Claims.

My present invention broadly relates to electrical amplifying means, but more particularly to such means in such a form as to be especially adaptable for amplifying electrical alternating currents.

The Federal Gommu-nicati'ons Commission has recently adopted the term very high fre-- quencies for referring to electrical alternating currents ranging frequencies from 30 to 300- megacycl'es and the term ultra high frequencies for the same purpose for the range" of from 300 to 3 ,000 megacycles. With the meanings thus given to these terms inmind, it is an underlying object of my'presen-t invention to obtain effective and. faithful amplification ofelectri'cal alternating currents while of any chosen frequency within a very wide range of frequencies that involves both of the said terms, such as at any frequency within a range of from 200 to 500* megacycles I' mention merely as an example:

Itis another underlying object of my present invention to make it possibleto operatively cover such a very wide: rangeof operations without having to make any readj ustments in the finally ad- J'usted means at any intermediate points or portions of such a range other than those adjustments necessary to selecting each individual frequency at which operations are desired for the particular use to which the said amplifying means may be put at any one time.

To practice my present invention, I associate with any typeot electron tube having construction and operating characteristics that I know to be suitable for my purpose the usual circuits and elements necessary to operation plus those means specifically adapted to making the overall combination perform in. amanner necessary to accomplishing my aforesaid objects and such other objects as may be readily apparent to those skilled in the particular art from the description thereof here to follow withv the aid of the figures of the: accompanying drawings in which like referencesymbols in the same refer to parts like in kind or in function.

Fig. l is a schematic illustration of all of the necessary elementsin: their respective relations to each other, but in which a consolidated portion of theelements are shown in cross-sectional form in order that they" may be more directly described and understood as to their respective contributory functions.

Fig. 2 is a cross-sectional view on the line XX of Fig. l viewed fromthe' left which, in its fullness, ignores that the particular portion of Fig. l is shown in cross-sectional form.

Referring to Fig. 1 the element T represents the usual container common to electron tubes contai'm'ng in spaced relations to each other in the order'nanred acathode c' which can be made electron emissive from being heated by heat given off by filament I when heated by current supplied by battery B, a grid-like element gt, a screen grid-likeelement 9?, a grid-like element g3 and an anode element a. To maintain when desired; an active electron stream or flow from cathode to anode the anode a is maintained at a sufilcient unidirectional positive electrical potential respect to the cathode by bein conductively connected to a source of unidirectional positive electrical potential, this case th battery B being indicated as such a source; To make the screen grid-likceiement 92 act to most effectively isolate the reactions in the anode side of the constructionfrom the cathode side" of the construction it. is alsc maintained at a substantial unidirectional:

positive electrical potential, but less than that of.

the anode by inserting sufficient resistance}? in its connection to thebattery B source of such potential, it being preferable, however, to provide a by-pass to the cathode for the electrical alterhating currents as by the indicated capacitance device 6.

is further shown a circuit connecting the grid-like element 91 to the cathode c containing the usual grid-leak R1 and shunted condenser C1 to maintain anegative bias with respect to the cathode on the particulargridelike element during operations and further containing a source AC of electrical alternatin currents in the usual a schematic electrical symbol therefor which is indicated as being variable with respect to frequencies by the arrow passing therethrough. The junction of the cathode with other circuits terminating therein is indicated as being grounded by the electrical symbol G, Resonance; of this circuit to any frequency of all of the, frequencies of operation contemplated is intentionally avoided. By maintaining the potential of the grid-like element g3 at the cathode" and ground potential as shown,

more stable overall operation is assured.

As to, the: output side of the combination, the anode a' is directly connected to one end of a good conductor of electricity L2 having its other end connected to the positive potential B through a resistance R2 intended to oppose the flow therethrough of the electrical alternating currents contemplated. This conductor is substantially paralleled by a second good conductor of e lectricity Ll which may, although it is not at all compulsory, almost surround conductor L2 to circular element P3 composed of-a good electrical insulating material, with the elementiP3 being further indicated as being so constructed as to electrically insulate the element P2 from the conductor L2. The element P2 is further indicated as being so circumferentially grooved that it can and n I where the slidable unit stops in adjusting for frequency, the characteristic surge impedance does contain therein a spring-like element Pd,

' also composed of good electrical ponducting; ma,-

terial, and thus acts as a goodelectricalcontactor between element P2 and conductor L1 Thepio jecting outwardly element M, aflixed as it is to the.

slidable unit, indicates a simple appendage for" back and forth in the directions indicated by the dotted line arrowheads Al and A2. Of course, the various elements of the slidable. unitcan be effec-' tively bonded together in theirproper relations with any one of many available, bonding cements. The inner end of conductor Ll is indicated as grounded through G.. 1

Fig.2 indicates that element Pecan, as one workable way, be made as hexagonal, spring-like element, open at one point as indicated at O, and that conductor Ll, if the two conductors ap-, proach a co-axial relationship, should be slitted as indicated by the open space K sufficiently to accommodate the slide control .element M asfar. asneeded at least. H v ,7

Since in dealing with electrical: alternatingcurrents of the very high. and .ultra high. fre-. quencies herein contemplated it isextremely important to keep electrical resistances aslow as available materials will permit and the conductivity of electrical contacts as perfectas reasona bly possible, I have found it quite advantageous to silver plate the surfaces of elements LI L2, PI

and PZand togo as far asmaking element B out of coin silver. The dielectric effect ofthe insulating material of the element P3 sets up an electrical capacitance between the elements PI and L2 onthe one,

hand. and the element P2 on the other hand, with the result that energy of any amplified electrical alternatingcurrent undertaking to flowin the anode-to-cathode circuit and/therefore, in the conductor L2, will in part spill over into con ductor Ll through the said capacitance and elements P2 and P4.. Accordingly, any circuit connected acrossconductorsLl and L2, can become a work circuit for the energy .thustransferred to conductor Ll as by connecting it across the far ends thereof as indicated by the connections to.

the arrowheads A3 and A4. In this, case, .the indicated capacitance C2 acts as .a so-called blocking condenser for the anodeeto cathode unidirectional current flow. a

By varying the position of the element and; therefore, the slidable unit to which it is afiixed,.

the frequency to which the resulting amplifier will resonate will correspondingly .vary, and I have found it entirely feasible to build well within commercially acceptable proportions such an amplifier capable of satisfactorily functioning as such at all of the points of the extremely wide range of from 200 to 500 megacycles with margin. to spare at each end of the same; provided, how ever, that the unused portion, irrespective ofv length, of the 2-conductor transmission line so created is terminated in a load as indicatedh terminated transmission lines dealing with electrical alternating. currents! of frequencies even much lowerythan the very, high freq'uencies herein contemplated are substantially eliminated to thereby make the amplification at all frequencies more nearly uniform and undistorted than would otherwise be the case.

Irrespective of involved remains substantially the same.

I am fully aware of thefact that it has heretofore been proposed by others to use a 2-conductor transmission line with a slidable, almost perfect manually or otherwise sliding the particular unit often being accompanied by the far end, of the line being shunted by a conductor in the manner merely indicated for reference: thereto by the broken line switchingmeans S of Fig. 1. *In thesecases, the output for any Workingcomponent-of.

energy is usually takendirectly from the anode of the tube used through. a coupling-condenser in the manner indicated-in Fig..1.by.-thebroken line connection to the arrowhead A5 through the illustrated in broken lines condenser C5, the

' other side of said output naturally. being terminated incathode C; Insuch cases, it is perfectly clear that irrespective of whether or not the'far end of said 2-conductor line is shunted the unused portion of the line involved is bound to be the breeding ground for serious disturbing effects when it becomes of the order of one-quarter, onehalf, three-quarters or any multiple of an operating wave length, allof which isibound to happen over and over again in attempting to cove any wide rangeof'frequencies.v 1

In the'case of my present invention, I have found that irrespective of whether or not the line is, of the so-called coaxial-type or-the open line2-conductor type, the functioning is to all intents and purposes fundamentally'the same.

.While I have made knownrthe nature of my present invention in certain confined respects,it is apparent that modifications maybe made and that no limitations are intended'other than those imposed by the scope of the appended claims.

What I claim as new'and' desire to secure by Letters Patent of the United .States is as'followsz 1. A wide range. amplifierfapparatus adapted to operate over a range of frequencies of the order'of 200 to 500 megacycles per second, comprising a multiple-electrode electron -tube hav ins an input electrode adapted to have impressed thereon signals to be amplified and withinsaid" frequency range and also having an anode and a; cathode; a section of coaxial line of predetermined length having inner and outer con ductors, adjoining ends of said conductors be ing respectively connected directly. to said oath ode and said anode; a capacitiveshunt for said line-section comprising a pair of conductive disk members relatively insulated from one, another and respectively conductivelyand slidably connected to said inner and outer conductors,,said

diskmembers being slidable along said conduc-v tors to provide an. adjustably'. positionably shunt capacitance across said coaxial line section, the portion of said line section between said shunt and the end of said line connected to said tube providing a tunable tank circuit for said tube with a resonant frequency determined by the length of said portion and hence by the position of said shunt, said shunt being adapted to transfer energy from said line section portion to the remainder of said line section; a terminating impedance element connected across the ends of said inner and outer conductors remote from said tube and having an impedance matching the characteristic impedance of said line section; and a pair of output terminals also connected respectively to said remote ends of said inner and outer conductors, whereby upon suitable adjustment of said shunt the portion of said line section between said remote end and said shunt forms a tuned tank circuit for said input signals, and the remainder of said line section forms an output coupling for the amplified signal.

2. Apparatus as in claim 1, wherein each of said conductive disk members is arranged per- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,132,208 Dunmore Oct. 4, 1938 2,169,396 Samuel Aug. 15, 1939 2,373,233 Dow Apr. 10, 1945 2,379,047 Thomas June 26, 1945 2,410,080 Kellogg Oct. 29, 1946

Images