US1465997A

US1465997A - Electron-tube apparatus

Info

Publication number: US1465997A
Application number: US279581A
Authority: US
Inventors: Harvey C Rentschler
Original assignee: Westinghouse Lamp Co
Current assignee: Westinghouse Lamp Co
Priority date: 1919-02-27
Filing date: 1919-02-27
Publication date: 1923-08-28
Anticipated expiration: 1940-08-28
Also published as: FR22767E; GB139514A; FR519666A

Description

Aug. 28, 1923.

P/a fe Carre/7T.

1,465,997 H. c. RENTscHLER ELEc'rnoN TUBE APPARATs Filed Feb. 27. 1919 WITNESSES:

and'

INVENTOR Har veg C. Rensch/el.'

'ya ATTORNEY Patented Aug. 28, 1923.

HARVEY C. RENTSCHLEB, 0F WILXINSBU INGHOUBE LAMP COMPANY, A C

RG, PENNSYLVANIA, ABSIGNUR T0 WEST- ORPORATION OF PENNSYLVANIA.

ELEGTRON -TUBE APPARATUS.

i Application tiled February .27, 1819. Serial No. 279,581.

"o all `whom it may coi/wem:

Be it known that I, HARVEY C. RENT- scHLi-m, a citizen of the United States, and a resident of lVilkinsbur in the county of Allegheny and State of ennsylvania, have invented a new and useful Improvement in Electron-Tube Apparatus, of which the following is a specification.

My invention relates to electron tube apparatus, as is used in the receipt of wireless impulses, and it has for its object to provide apparatus of the character designated that shall cause a relatively large percentage change in the controlled currents with a relatively weak controlling current by virtue of the phenomeno-n of resonance.

Other objects of my invention are to providefapparatus of the character designated that shall be positive in operation and which shall maintain the desired operating characteristics over relatively long periods of time.

Fig. l of the accompanying drawing is a diagrammatic view of a detector tube, together with associated auxiliary circuits embodying a preferred form of my invention; Fig. 2 is a diagram illustrating the operating characteristics of a system of this character; and Fig. 3 is a sectional view of a tube illustrating the phenomenon of resonance potential.

Two types of inelastic impacts between electrons and atoms in certain monatoniic ses and vapors have been found to exist. llie first occurs when the colliding electron displaces an electron of the atom without removing it from the atom. That is, it moves an electron from one orbit to another in the same atom. The phenomenon of electronic displacement in the atomic system, without removal of an electron, is called resonance. The potential through which the colliding electron must fall to acquire the necessary velocity to produce such displacement is known as the resonance vlpotential for the gas or vapor in question. he second type of inelastic impact occurs when the colliding electron removes an electron from the atom and produces ionization.

The phenomenon of resonance exhibited by argon and b certain metal vapors is now well recognize and exhibits itself as follows. If a three-electrode tube be filled, for example, with argon gas, at a given pressure, and electrons attempt to force their way therethrough, as from the hot cathode, it is found that the action changes materially with different velocities of the electrons. At a given velocity, an electron either passes complete] through an argon atom or rebounds t erefrom with an elastic impact, being substantially unaffected thereby and producing substantially no effect thereon. As the velocity of the electron increases, it apparently approximates the velocity of the electrons Within the atom or has some other critical relation thereto, as a result of which the impact becomes non-elastic and a large portion of the energy of the impacting electron is taken up in displacing an electron ot' the atom and its velocity is thereby decreased.y The resultant electron velocity is relatively low so that such electrons are taken up by the adjacent grid or screen electrode. As the accelerating screen potential is raised higher and higher, the critical volocity is reached at a greater and greater distance therefrom, so that the resultant electrons move at higher and higher velocity when reaching the neighborhood of the screen. As a result, a larger and larger percent-a e thereof pass therethrough and reach the p ate, affecting the late current. At a certain point, the velocity of the electrons becomes so high before they reach the screen that a second non-elastic impact is produced, with the production of low-velocity electrons which are also drawn to the screen. This cyclical action s on with an indefinite number of repetitions as the screen potential is raised until interrupted by extraneous phenomena.

1 have found that use may be made of this phenomenon in producing a detector or amplifier that operates with extreme reliability and sensitiveness. I find that particularly favorable results may be secured by employing the intermediate sci'een for the control of the electron velocity and by maintaining the. plate electrode negative with respect to this screen, so that the potential gradient between the screen and the plate p-revents those electrons, the velocity of which has been seriously impaired b virtue of resonance, from reaching the plate. Said potential gradient is not sufficiently pronounced to prevent those electrons that have suffered merely an elastic impact or which have passed through a gas particle without material modification of their velocity from reaching the plate.

Referring to the accompanying drawing for a more detailed understanding of my invention, I show a detector bulb at 3, preferably filled with argon gas and containin a plate electrode 4, a iilamentary catho e 5 and an intervening screen or grid 6.

The screen 6 is maintained plositive with respect to the filamentary cat ode 5 by a B battery 7, and the flamentary cathode 5 is maintained at incandescence by an battery 8. In like manner, the screen 6 1s maintained positive with respect to the plate electrode 4 by a suitable battery 9, the receiving apparatus 10 of any desired form being connected in the latter circuit. h

Incoming impulses, as from a suitable antenna 11, are superposed on the circuit by a suitable transformer 12, as is usual 1n the art, between the ilamentary cathode and the screen. A condenser coupling instead j of a transformer may also be used.

Having thus described the structure of apparatus embodying my inventlon, the operation thereof is as fol ows.

Referring to Fig. 3, let it be assumed that the potential pf the screen 6 is such that an electron emitted from the cathode 5 is accelerated to such a velocity as to have a non-elastic impact at a point 20 adjacent to the screen. Certain of the electrons which have not suffered non-elastic impact pass through and impinge upon the late 4, determinn the plate current. hose electrons which had suffered a non-elastic impact at a point, such as 20, however, escape from this impact with relatively low veloeity and are, therefore, taken up by the screen 6. Thus, there is a diminution in the electrons received by the plate 4 and, consequently, in the plate current. As the screen potentlal is raised, the acceleration of the electrons emitted from the cathode 5 is greater and greater and these electrons reach a velocity corresponding to nonelastic impact at a point such as 21, further from the screen. The electron therefore receives pronounced acceleration before reaching the screen 6 and may, therefore, pass therethrough and reach the electrode 4 so that the plate current is gradually increased.

lVith still further increase in the screen potential, the initial non-elastic impact may occur at a point 22 so that the electron again reaches the critical velocity corresponding to non-elastic im act at some such point as 23 adjacent to t e screen. The electron is t en up by the screen, and, as a result, the` plate current is again reduced.

This c lical change in the plate current, with an increase in the screen-potential, obtains until extraneous phenomena intervene and prevent further electron action.

Referring to Fig. 2, the potentials of the screen, determining the initial velocities of 1Macc-r the electrons, are plotted as absciss against the plate current as ordinates and the eilect of resonance is to cause the characteristic curve to assume the form shown, having

peaks

15 and 16 and a minimum point or trough 17. The peak 16 may correspond to the conditions as described at the point 21 and the trough 17 as corresponding to the point 20.

Assume that the batteries 7 and 9 are so adjusted as to determine the screen potential at a value plroducing a given velocity of electrons suc that there is either maximum or minimum disturbance thereof by the phenomenon of resonance. If there is a maximum disturbance thereof by screen potential, the number of electrons, the velocity of which is materially lowered, is a maxlmum and these electrons are turned back by the potential of the grid and never reach the plate electrode, thus causing a decreasing plate current. If, on the other hand, the screen potential is adjusted to establish an electron velocity such that there is minimum interference from the gas atoms substantially all electrons have such a velocity that they reach the plate electrode without diiiiculty, producing an increasing plate current.

Let it be assumed that the adjustment is such as to cause operation corresponding to the point 15 in Fi 2. An incoming impulse of such polarity as to add to the potential of the battery 7 carries the total screen potential to a value 18 and the associated lmpulse of the other polarity pan tially neutralizes the voltage of the battery 7 and carries the screen potential to a point 19. Thus, the average effective plate current during the receipt of impulses is substantially of the value shown by the line {iO-31, substantially midway between the line 19-18 and the point 15 and is suiciently different from its normal value to produce distinct audition at the receiver 10, even with extremel weak incoming signals.

While I have escribed operation at a peak 15, the adjustment of the battery 7 may readily be made such that operation is secured at the trough 17 or at the peak 16. Obviously, with operation at the trough 17, the normal adjustment of the current is to a minimum value and the current increases with a potential increase on the screen or with a potential decrease.

I wish to direct particular attention to the fact that a bulb of the above-described Uli character has definite peaks and troughs f which ma be used as operating oints, as distinguis ed from certain bulbs o the prior art wherein the characteristic curves had merely knees. It will be noted that, when operating with a trough or peak, the average or effective current in .the output circuit during the receipt of impulses is substantially" one-half the total current variatin,f` whereas, when` pperating -on a knee, the f'elective current is substantially onelialf the difference between the current inlicrease and the current decrease.

The following marked distinction should be noted between the operation of a tube embodying the resent invention and the ,ordinary three-e ement tube of the prior 10,1`iirt.y In the latter device, the grid or intermediate electrode performs merely a passive function so far as concerns giving velocity to the emitted electrons, in that the electrons emitted from the cathode move at \sutlicient velocity, duc to the joint action of tion, yand the plate acts as the the`catliode and anode alone, to carry them to lthe aridekeither directly or indirectly, and the grid exerts a retarding influence, when of suliiciently low potential, thus de- 2 termining the number of electrons reaching the 3 art, the low potential of the intermediate grid electrode has beenthe controlling factor and little or no energy was taken therefrom, whereas, with the present tube, there is necessarily energy abstraction from the screen electrode and, accordingly, a iiow of current thereto.

While I have illustrated the use of a bulb of the character described as a detector bulb for the receipt of Wireless impulses, it will be obvious to those skilled in the art that it is susceptible of application in many other relations where it is desired to modulate a local current by a controlling current, as in amplifiers and other forms of apparatus.

A still further use of this invention is a frequency doubler, it being obvious that a change in the modulating potential from the point 19 to 18 and back again causes two modulations in the plate current, and

5 this phenomenon may be made use of in various applications. l

I Icontemplate the use of this invention in tubes which perform merel a relaying action with but little excess o modulated current over modulating current or as applied to tubes where there is a pronounced difference between the twocurrents and also as covering those tubes whose primary function is largely integration of high-frequency im ulses.

ile I have shown my invention in a preferred form, it will be" obvious to those skilled in the art that it is not so limited but is susceptible of various minor changes and modifications without departing from the spirit thereof and I desire, therefore, that only such limitations shall be placed thereon as are imposed by the prior art or are specifically set forth in the appended claims. A

I claim as myl invention:

.1. In an electron tube, the combination with an electron source, of a plate electrode, and an intervening screen electrode, said tube being filled with a medium exhibiting the phenomenon of resonance.

2. The combination with an electron tube provided with an electron source, a plate electrode an intervening screen electrode and a filling of a medium exhibiting the phenomenon of resonance, of means for maintaining said plate electrode at a positivepotention, and means for modulating the potential of said screen electrode.

3. The combination with an electron tube provided with an electron source, a plate electrode, an intervening screen electrode and a filling of a medium exhibiting the phenomenon of resonance, of means for maintaining said plate electrode at a positive potential, means for maintaining said screen electrode positive with respect to both of said remaining electrodes, and means for modulating the potential of said screen electrode.

4. An electron tube comprising an electron-emitting electrode, a screen and a plate 1n said tube and a gaseous filling for said tube, and means to give a periodic screenpotential plate-current characteristic with values above zero.

5. An electron tube comprising an electron-emitting electrode, a screen, and a plate, means to give to said screen a potential positive with respect to said electrode and plate and further means to give to the screen-potential plate-current a rising and then a falling characteristic, said falling characteristic followed by a rising characteristic and the whole of said characteristic never falling to zero.

6. An electron tube comprising an electron-emitting electrode, a screen and a plate in said tube and a gaseous fillin for said tube, and means to give a peri ic screenpotential plate-current characteristic with values above zero, said means being adjustable so as to work said tube at a point of the characteristic when the slope sign of the characteristic changes.

7. The method of operating an electron tube having a screen-potential, pleite-curient characteristic with fportions of positive and negative slopes an containing a medium 'exhibiting the phenoliienon of resonance which comprises adjusting the nonmodulated screen-potential to a point of the characteristic where the sign of the slope changes. l 8. if an electron tube, a filling of a medium exhibiting the phenomenon of resonance, electron-emitting and receiving means, and means whereby a controlling force modifies the velocity of said electrons so that the degree of retardation thereof by said medium is modified.

9. The method of operating an electron tube provided with e ectron-emitting and electron-receiving means, with a filling or a medium exhibitin resonance and with means for controlling the electron velocity, which comprises adjusting said last-named means for an electron velocity of vmaxlmum or minimum retardation by the yresonance of said medium and thereafter modulating sani last-named means.

10. An electron tube comprising an electron-emitting source, an electron-receiving source, means forA modifying the electron velocity therebetween, and a filling of a medium exhibiting the phenomenon of resonance.

11. An electron tube'comprising an electron-emitting source, an electron-receiving source, means for 'abruptly modifying the electron velocity therebetween,- and a filling of argon gas, under such conditions as to exhibit the phenomenon of resonance.

12. An electron system comprising a tube provided with electron-emitting means, electron-receiving means, means for controlling the electron velocity abruptly therebetween, before reaching said electron-receiving means, a filling of argon gas under such conditions as to exhibit the phenomenon of resonance, means for applying the controlling effect in modifying said velocity-controlling means, and means for establishing a controlled current in accordance with the number of electrons reaching said electron receiving means.

13. An electron system comprising a tube provided with an incandescing electrode, an electron-receiving electrode, an intervening perforated electrode, and a filling of argon gas, means for maintaining said electron-receiving electrode ositive with respect to said incandescing e ectrode, means for maintaining said perforated electrode positive with respect to both of said remaining electrodes .means for controlling the potential of said perforated electrode, and means for establishing a controlled current in accordance with the electrons reaching said .electron-receiving electrode.

14.'An electron tube comprising an electrop-emitting cathode, an anode and a ,grid therebetween, said elements being enclosed in a medium exhibiting the phenomenon of resonance and means for maintaining a oon- Stant potential dierence between the anode and grid while applyin a Vmodulating influence between them an the cathode.

15. The method of operating an electron tube provided with electron emitting, controlling and receiving means in an atmos phare of a medium exhibiting the phenomenon of resonance, comprising applying cons stant potentials between said emitting, controlling and receiving means while impressing a modulating potential between the emitting means and the controlling and receiving means.

In testimony whereof, I have hereunto subscribed my name this 24th day of Feb., 1919.

HARVEY C. RENTSCHLER.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1465,997, anted August 28, 1923, upon thc application of Harvey C. Rentschler, o Wilki urg, Pennsylvania, for en lmproi'ement in Electron-Tube Apparatus, errors appear in the printed specification requiring correction as follows: Page 1, line 30, strike out the word potential, and line 75, for the syllable voread lve,' ge 3, line 68, for the word thereon. read thereupon, and line 83, claim 2 for the misspelled word potention read potential; and that the said Letters atent should be need with these corrections therein that the same may conform to the record of the case in the Patent Otice.

Signed and sealed this 30th day of October, A. D., 1923.

[emu] 4 KARL FENNING,

Acting Uommn'amr of Patente