US2138920A - Secondary emission tube and circuit - Google Patents

Secondary emission tube and circuit Download PDF

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Publication number
US2138920A
US2138920A US126111A US12611137A US2138920A US 2138920 A US2138920 A US 2138920A US 126111 A US126111 A US 126111A US 12611137 A US12611137 A US 12611137A US 2138920 A US2138920 A US 2138920A
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United States
Prior art keywords
electrons
grid
potential
circuit
cathodes
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Expired - Lifetime
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US126111A
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English (en)
Inventor
Hollmann Hans Erich
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Telefunken AG
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Telefunken AG
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Publication date
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B9/00—Generation of oscillations using transit-time effects
    • H03B9/01—Generation of oscillations using transit-time effects using discharge tubes
    • H03B9/10—Generation of oscillations using transit-time effects using discharge tubes using a magnetron
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/50—Magnetrons, i.e. tubes with a magnet system producing an H-field crossing the E-field
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/76—Dynamic electron-multiplier tubes, e.g. Farnsworth multiplier tube, multipactor

Definitions

  • the electron tubes serving for the production of electrical oscillations operate with glow emission, i. e., the electrons sustaining and controlling the oscillation mechanism are emitted by a glow cathode whose heating in case of larger tubes, requires considerable power.
  • tubes have become known which operate exclusively with secondary electrons instead of glow cathodes, said secondary electrons are released from the atomic structure of the cathode surface when primary electrons impinge thereon. In these tubes the cathode or cathodes remain cold so that no special heating is required.
  • Fig. 1 In order that an electron current be continuously and exclusively sustained by secondary emission, it is necessary that all or part of the electrons once produced, again and again release new secondary electrons, and this in greater numbers or at least in a number equal to that being lost by the transit to the anode or to other absorption electrodes.
  • items K1 and K2 are two fiat cathodes which, however, do not emit as such but are covered with layers having secondary emission property of great yield such as cesium oxide layers. As is known, such layers are capable of giving up a number of secondary electrons, that is, ten to twenty times the number of primary electrons impinging thereon with a sufficiently high velocity.
  • a suitable anode A is arranged which must be wholly or partially permeable as regards fr the electrons passing towards it.
  • a grid-shaped anode A is shown catching a small part of the electrons, while the greater part passes unhindered through its meshes.
  • the scheme is not changed if the real grid anode is replaced by a virtual acceleration grid, for instance in the form of an anode ring or the like surrounding the discharge space.
  • stance photo-electrons may at first be emitted. These electrons are being accelerated by the grid, and a part thereof arrives at the opposite cathode, where they may release, for instance, ten times as many secondary electrons. These return again to the first cathode and produce thereat a still greater number and so on. In this way the total emission is gradually enhanced until a final stationary state is reached, determined either by the limited yield of the cathodes or else by the space charges.
  • the excitation of oscillations in such an arrangement can be conceived in the simplest manner as pendulum movements of the electrons, as known from the Barkhausen retarding field method, more especially from the push-pull retarding field tubes.
  • the only difference existing resides in that the electrons do not reverse their course in front of the cathodes on both sides, and that therefore a certain electron cloud can. oscillate b-ack and forth several times, but instead thereof, in each half cycle, a new electron cloud is produced and introduced in the oscillation performance.
  • the control potential must in this case have the following course: As long as the electrons are, for instance, between K1 and A, i. e., in the first half of the half of the pendulum movement, the plate potential may have a certain definite value. As soon as, however, the electrons have passed the grid, the plate potential must be lowered so as to reduce the intensity of theretarding field to such a degree that the electrons impinge on K2 with the necessary residual velocity. In the subsequent quarter cycle of the pendulum movement of the electrons during which the newly released secondary electrons fly towards A in the opposite direction, the grid potential can again resume its original value but it is then necessary that in the last quarter cycle, i.
  • the grid potential is again reduced in order that the said excess velocity also of the electrons passing towards K1 be retained-
  • the control potential of the grid must vary during each half cycle, i. e., during each electron movement from one cathode to another one, from a maximum to a minimum and again back to a maximum which is at fully 360, or in other words, the control potential at the grid must have twice the frequency of that which would be used if the control potential were applied to the cathodes.
  • the lower part shows the movement as to time of two secondary electron clouds in the direction from K1 to K2 (full line) and in the direction from K2 to K1 (dash lines).
  • the apertaining course as to time of the grid potential.
  • the grid potential In the first quarter cycle of the electron oscillation considered from K1 back towards K1, the grid potential is negative, and the electrons are accelerated in a corresponding degree.
  • the alternating grid potential will be reversed, so that the electrons receive in the average a weaker deceleration than would correspond to the preceding acceleration, and the electrons impinge on K2 with the velocity component remaining as difference.
  • the phase of the alternating grid potential is reversed in accordance with the reversed direction of the electron movement.
  • the described performances are not necessarily confined to the double frequency of the control potential of the gird, but can. also be applied in an analogous manner to higher harmonies of the pendulum-movements of the electrons as long as the fundamental principle is retained, namely that the electrons after passing through the grid-anode are less retarded in both directions than they have been accelerated previ ously.
  • the described performance is of importance in various respects. In the first place,'it is obvious that if the transmitter produces itself in a corresponding manner its control potential, the resonance system placed at the grid can be tuned to the double frequency which the resonance circuit, situated between the cathodes, would have.
  • the new arrangement thus furnishes principally a frequency which is twice that produced with the same tube dimensions and operating conditions in the hitherto customary arrangements. Furthermore, the new arrangement owing to the effect described, is well suited for frequency multiplication.
  • the pendulum movements of the electrons are controlled in the hitherto customary manner by an alternating potential between the cathodes, whereafter in accordance with the invention, in the grid circuit a resonance circuit tuned to a multiple of this control frequency can be excited.
  • a resonance circuit tuned to a multiple of this control frequency can be excited.
  • it can also be produced'in the cathode circuit by the self-excitation above described. This method has a particular advantage when ultra-high frequency oscillations are to be stabilized by a quartz or turmaline crystal.
  • the control crystal may then, of course, be inserted in the cathode circuit and stabilizes at first the pendulum movements of the electrons, whereafter on the basis of the multiplication effect afore described in the grid circuit, an oscillation can be derived whose frequency is twice the crystal frequency or a multiple thereof.
  • FIG. 1 illustrates a known oscillator arrangement
  • Fig. 2 is given to explain the time relations of the electrons in their travel between the cathodes with respect to the potentials applied to the electrodes.
  • Fig. 3 shows my new arrangement wherein the grid electrode itself is designed as the resonance system to be excited.
  • the grid leadin is connected to the center of the grid A in which an oscillation node exists, while at the grid ends oscillation loops appear in accordance with the voltage distribution shown in dash lines.
  • the entire tube may obviously also be constructed with cylindrical electrodes whereby the grid anode consists of an open or closed helix.
  • the ratios between the radii of the three electrodes are to be so chosen preferably that the electron travel times are possibly the same in the space inside and outside the grid. Otherwise all features known from the ultra short wave field can be applied to the new arrangement.
  • an electron discharge device comprising an evacuated envelope containing a pair of parallel surfaces capable of emitting electrons on impact, said surfaces being oppositely disposed and parallel with respect to an intermediate grid collecting element, said grid having an overall length equal to half the length of the operating wave, and means for applying to the center of said grid a potential which is positive With respect to said surfaces.
  • an electron discharge device comprising an evacuated envelope containing a pair of parallel surfaces capable of emitting electrons on impact, said surfaces being oppositely disposed and parallel with respect to an intermediate grid collecting element, said grid having an overall length equal to half the length of the operating wave, a direct connection between said surfaces, a circuit coupled between the center of said grid and said surfaces including means for applying to the center of said grid a potential which is positive with respect to said surfaces.
  • an electron discharge device comprising an evacuated envelope containing a pair of parallel surfaces capable of emitting electrons on impact, said surfaces being oppositely disposed and parallel with respect to an intermediate grid collecting element, said grid having an overall length equal to an odd multiple including unity of half the length of the operating wave, and a circuit coupled between an oscillation nodal point on said grid and said surfaces for applying to said grid a potential which is positive with respect to said surfaces.

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  • Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
  • Microwave Tubes (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
US126111A 1936-04-20 1937-02-17 Secondary emission tube and circuit Expired - Lifetime US2138920A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE494230X 1936-04-20
DE2138920X 1936-04-23

Publications (1)

Publication Number Publication Date
US2138920A true US2138920A (en) 1938-12-06

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ID=32043856

Family Applications (2)

Application Number Title Priority Date Filing Date
US126111A Expired - Lifetime US2138920A (en) 1936-04-20 1937-02-17 Secondary emission tube and circuit
US133316A Expired - Lifetime US2171212A (en) 1936-04-20 1937-03-27 Electron discharge device

Family Applications After (1)

Application Number Title Priority Date Filing Date
US133316A Expired - Lifetime US2171212A (en) 1936-04-20 1937-03-27 Electron discharge device

Country Status (4)

Country Link
US (2) US2138920A (enrdf_load_stackoverflow)
FR (3) FR820665A (enrdf_load_stackoverflow)
GB (1) GB494230A (enrdf_load_stackoverflow)
NL (1) NL56591C (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4453108A (en) * 1980-11-21 1984-06-05 William Marsh Rice University Device for generating RF energy from electromagnetic radiation of another form such as light

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2648028A (en) * 1941-08-22 1953-08-04 English Electric Valve Co Ltd Magnetron
US2624863A (en) * 1945-10-10 1953-01-06 Albert M Clogston Self-modulated magnetron
US2819449A (en) * 1954-01-21 1958-01-07 Rca Corp Magnetron

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4453108A (en) * 1980-11-21 1984-06-05 William Marsh Rice University Device for generating RF energy from electromagnetic radiation of another form such as light

Also Published As

Publication number Publication date
US2171212A (en) 1939-08-29
NL56591C (enrdf_load_stackoverflow) 1944-07-15
FR48401E (fr) 1938-02-08
FR820665A (fr) 1937-11-16
GB494230A (en) 1938-10-20
FR50605E (fr) 1941-01-27

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