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US2201731A - Discharge tube electrode assembly - Google Patents

Discharge tube electrode assembly Download PDF

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Publication number
US2201731A
US2201731A US243101A US24310138A US2201731A US 2201731 A US2201731 A US 2201731A US 243101 A US243101 A US 243101A US 24310138 A US24310138 A US 24310138A US 2201731 A US2201731 A US 2201731A
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US
United States
Prior art keywords
heater
heat
electron
emitting
cathode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US243101A
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English (en)
Inventor
Albert W Hull
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Co
Original Assignee
General Electric Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by General Electric Co filed Critical General Electric Co
Priority to US243101A priority Critical patent/US2201731A/en
Priority to US261395A priority patent/US2201720A/en
Priority to US266803A priority patent/US2246176A/en
Priority to US283803A priority patent/US2201721A/en
Priority to GB31133/39A priority patent/GB536070A/en
Priority to FR861969D priority patent/FR861969A/fr
Priority to NL96091A priority patent/NL55022C/xx
Priority to FR51138D priority patent/FR51138E/fr
Application granted granted Critical
Publication of US2201731A publication Critical patent/US2201731A/en
Priority to GB11440/40A priority patent/GB542495A/en
Priority to BE438749D priority patent/BE438749A/xx
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/13—Solid thermionic cathodes
    • H01J1/15—Cathodes heated directly by an electric current
    • H01J1/16—Cathodes heated directly by an electric current characterised by the shape
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/13—Solid thermionic cathodes
    • H01J1/20—Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00—Gas-filled discharge tubes with solid cathode
    • H01J17/02—Details
    • H01J17/04—Electrodes; Screens
    • H01J17/06—Cathodes
    • H01J17/063—Indirectly heated cathodes, e.g. by the discharge itself

Definitions

  • the present application relates to electrical discharge devices. It is the object of my invention to provide for such devices improved thermionic cathodes, and in particular cathode constructions vated electron-emitting temperature, and will operate with improved characteristics.
  • Such large cathodes were constructed to provide heat conduction paths from the source of heat to electron-emitting members.
  • theelectron-emitting members are constituted by. vanes of sheet metal which are mounted upon and in good heat-conducting relation to a hollow metal cylinder.
  • inder which acts as a heat shield, this cylinder also being connected to the vanes at their extremities.
  • a structure is thermally stable, but it has the disadvantage of heating to operaing temperature slowly from a cold state.
  • the heat conduction paths of such a structure either are inadequate to transmit heat at a sufficiently high rate to materially reduce the heating period (without fusing or otherwise injuring the base of the vanes), or, if the heat conduction paths are made larger, e. g., by making the vanes thicker, then the required amount of heat is increased which offsets the in-' crease of heat conduction so that nothing is gained.
  • the primary heater is constructed'to efi'ectively heat electron-emitting members to an operating temperature by radiation instead of by conduction;
  • the electron-emitting members are of relatively small mass and have small heat capacity. Preferably theyconsist of ribbons or reticulate material, such asmetal mesh or gauze.
  • a surrounding heat shield which is constructed to operate efliciently as a secondary radiant heater which receives heat from the primary heater whereby it may be maintained at a temperature as high as the electron-emitting members.
  • the combined effect of the primary and secondary radiation heaters quickly'heats the otherwise substantially thermally-insulated electron-emitting members to an operating temperature.
  • the electronemitting members are so constructed and arranged that opposite emitting surfaces can effectively contribute electron emission for a space discharge supported by the cathode.
  • Figs. 1- and 2 are vertical and horizontal sections of a cathode embodying my invention, the respective sections being taken at regionsindicated in the companion figure by lines and arrows;
  • Fig. 3 is a fragmental sectional figure showing structure of the heat shield;
  • Fig. 4 is a side elevation, partly in section, of a complete discharge device containing a cathode embodying my invention;
  • Fig. 5 is a fragmental view of a modified heater;
  • Fig. 6 is a side elevation, partly in section, of a modification in which the electron-emitter is a helical ribbon;
  • ⁇ Fig. '7 is a top view of the same structure;
  • Figs. 8, 9 and 9a are side elevations, partly in section, of other modifications (part being broken away) in which the heater also serves as a source of material for enhancing electron emission; and Figs. 10 and 11 are fragmented enlarged views of wire mesh structure.
  • the cathode structure shown in Figs. 1 to 3 comprises a radiant heater I, which may consist of a heavy filament or .wire of tungsten, tantalum, or other suitable refractory material. Itis helically wound on a core, or support 2, of suitable refractory insulating material, such for example as beryllia or alumina.
  • the core 2 is held in a fixed position by a heat-resistant wire I which passes through it and is embedded in the insulating supports 4 and 5.
  • the latter may consist of alumina.
  • the primary heat source may consist of a filamentary resistance heater, which may or may not be mounted on a support, but which is surrounded by a housing which functions as the heat-radiating member.
  • a housing 8 consisting of molybdenum, tantalum, or other suitable material.
  • a plurality of electron-emitting structures numbered 1 to I2 Surrounding the primary heater I are a plurality of electron-emitting structures numbered 1 to I2, each of which preferably consists of fillets or strips of wire mesh, or gauze, or metal foil, or a combination of foil and gauze. Any suitable structure of small mass and large surface area may be used, which herein will be termed generically as foil. As will be pointed out, these strips or ribbons are supported to receive radiant heat but are in poor heat-conducting relation to the heater. They may be arranged to present only their edge surface to the heater I. In this position they are nonobstructive to heat radiated directly from the heater.
  • the electron-emitting ribbons I to I2 are held between the metal supports I3 and I4.
  • the washer-shaped upper support I3 is re-enforced by a disc I5 and is mounted upon the heater core 2 near its upper end.
  • the lower. support I 4 is a flat ring or washer and is held by the refractory insulators I6 and I! which may consist of alumina or beryllia and serve also to support a surrounding apertured enclosure I8, which functions as a shield and secondary heater.
  • the structure may be rigidly clamped by tightening the nuts I9, I9 upon the terminals 20, 2
  • the electric circuit for the heater I may be traced from a conductor 22 through the heater to the support I3, through the ribbons I to I2, and to one of the treminals 20, 2
  • the heat shield I8 may assume various forms and even may consist of refractory nonconducting material, but it consists preferably of a plurality of closely spaced walls, or layers, which are in poor thermal contact with one another.
  • the shield may consist of layers of metal foil, such as nickel or molybdenum, through which indentations or holes are impressed so as to produce protuberances.
  • the layers of foil are superimposed, as by winding the foil on itself, the protuberances at the holes 23 space the adjacent layers from one another, as shown considerably magnified by Fig. 3. Heat conduction from one layer of foil to the next through the protuberances is slight. Although five layers of perforated sheet metal are shown assembled in Fig. 3, a greater or lesser number can be used as occasion may demand.
  • the foil may have a thickness of about $4, inch.
  • This structure provides a steep heat gradient path transversely from the interior to the exterior wall, thereby permitting the interior of the heat shield to be quickly heated and economically maintained at an elevated temperature.
  • The-heat shield may operate with its interior wall at a temperature as high'as, or even higher than, the normal operating temperature of the ribbons I to I2, or whatever form the electron-emitting members may assume.
  • the heater I may be operated at a temperature of about 1500 to 1800 C.
  • the heat shield I8 may be constructed and proportioned to become heated at its interior surface to a temperature of 850 C.
  • the ribbons when radially mounted, receive little direct heat from the heater I, are mainly heated by radiation received upon their activated surfaces from the heat shield.
  • Cathodes constructed "according to Fig. l may be quickly heated to an electron-emitting temperature by operating the heater during the starting, or warming-up period at a temperature above the normal operating temperature, and as high as about 2300 C., and then reducing the temperature to a desired operating value. In this way the starting period may be as short as 30 seconds.
  • a cathode constructed as herein shown and described may be mounted in any suitable electron discharge device of which many forms are known.
  • Fig. 4 one such device comprising an elongated glass envelope, or container, 28 in which is mounted the assembly 29 (such as herein shown), an anode 30, and a grid 3
  • the envelope contains also a charge of gas, such, for example, as argon, or other rare gas, which may be at a pressure within the limits of several microns to several millimeters; or an easily vaporizable metal, such as mercury or caesium, as indicated at 32, or some combination of these.
  • the anode may consist of graphite or metal.
  • may have the form of a perforated plate and may consist of graphite. It is attached by the screws 34 to a tubular shield 35 which is supported at the anode end upon a glass stem by a clamp 36 and at the cathode end by wires, two of which are shown in Fig. 4 as 31, 38. These support wires are spaced from the cathode by insulators (Fig. 2), two of which, 39 and 40, are shown in Fig. 4. This structure is mounted, as indicated, upon a stem 4
  • , and 22 are sealed into the stern 4
  • Current for operating the heater I may be supplied by the conductors 20 and 22.
  • Connection to a circuit (not shown) for supplying space current may be made by the conductor 2
  • the interior surface of the heat shield may be coated with oxide, or
  • activating material for example, barium or strontium oxide, or both, for replenishing the coating on the electron-emitting ribbons.
  • Electron emission does not occur to an appreciable degree from the heat shield which is connected to the cathode by a circuit containing an impedance 48.
  • This impedance may take the form of a resistor having a resistance within a range of one thousand to one million ohms.
  • the impedance 48 has a resistance value of 10,000 ohms, the heat shield space current to the anode is only .001 or one per cent of the normal cathode current.
  • a high resistance element connected between the heat shield and the active emitting part of the cathode is indicated diagrammatically by the rectangle 48.
  • the impedance (resistor) 48 may be omitted, the heat shield being connected directly to the coated ribbons and may take part in the emission of electrons.
  • the electron-emitter 48 which may consist of wire gauze, as described in connection with other figures, has the form of a helically-wound ribbon, the turns of which are spaced apart.
  • the emitter 48 surrounds in spaced relation a heater 48 whereby it is heated to an electron-emitting temperature, the heat being radiated by the heater and reradiated by the heat shield 58.
  • the ribbon 48 is supported by longitudinally extending spaced support wires, two being indicated at 58 and 5
  • pass through insulating bushings 52 and 58, and serve also as current-conveying conductors.
  • One end of the heater 49 which may consist of tungsten, or other suitable refractory material, is connected to a conductor 54 passing through an insulating bushing 55.
  • the other end is connected to a plate 56 and a metal yoke 51 (see Fig. 7).
  • These members in turn are carried by and connected to the heat shield 58.
  • the latter may consist of multiple layers of thin sheet metal as described in connection with Figs. 1 3.
  • the ribbon 48 may be coated .with emission-enhancing material, such as alkaline-earth oxide.
  • the emission of electrons from the heated ribbon 48' to the anode or anodes occurs through a circular aperture 59, although apertures may be provided elsewhere, as shown for example in the modification illustrated by Fig. 8.
  • Electric energy for the heater may be derived from any suitable source, as here represented by a transformer 60.
  • a high resistance connection between the electron emitter and the heat shield is provided at 8
  • Electric connections to the electron emitter 48 and to the anode (not shown) from a source of current (represented by the terminals 62) are indicated at 63 and 63', a resistance 84 being included.
  • the ribbon 48 being supported circumferentially intercepts a greater proportion of heat radiated from the heater than the radially supported ribbons of Figs. 1 and 2, and hence is heated even more rapidly to an electron-emitting temperature.
  • Serial No. 261,395, filed March 11, 1939, by Thomas A. Elder specific claims are made for the structure of Figs. 6 and 7.
  • the heater 85 consists of a closely woven wire-mesh structure which dispenses a supply of barium or some compound of barium, or other material for enhancing the electron emission of the electron-emitting members 88 and 81.
  • a closely woven wire-mesh structure which dispenses a supply of barium or some compound of barium, or other material for enhancing the electron emission of the electron-emitting members 88 and 81.
  • the heated structure being itself an electron emitter, it here dispenses by vaporization a supply of electron-emissive material for detached uncoated electron emitters, only two of which are shown at 86 and 61. A greater number may be used.
  • the dispenser 65 may consist of a sheath 68 of closely woven wire, for example, molybdenum, and contains a supply of alkaline-earth oxide, or a mixture or compound of an alkaline earth oxide with a refractory oxide, such as alumina (with or without an associated reducing agent).
  • the oxide and apparently also alkaline earth metal which is formed by reduction during operation) slowly migrates to the surface of the dispenser and evaporates, thus maintaining an active coating on'the electron emitters.
  • the dispenser 65 is provided with a coreconsisting of a wire 69 surrounded by a coating 10 of alumina, ceria, or other suitable refractory material around which is packed the source composition ll from which the activating materialis derived.
  • the coating 10 may be applied as a paste or may be preformed.
  • the purpose of the coating 10 is to insulate the wire 68 from the source material in case this wire is used as a heater to supply part of the heat. In case the wire is merely a mechanical support, or a return lead for the heating current, the coating "still is desirable but is not necessary.
  • the source composition H here is shown as granular, although it may assume other forms.
  • the dispenser may be heated by current passing through the core wire 88 and the. sheath 68 which are connected in series with one another by the metal plug 12.
  • the core wire is supported by a plate 13 which rests on theinsulators 14 which in turn are supported by the heatshield 15.
  • the heat shield 15 is provided with apertures 16 for the egress of the discharge during operation.
  • composition H consist of barium oxide, with or without a reducing agent such as molybdenum
  • its operation at an elevated temperature results in the migration from the interior to the exterior of the closely woven mesh 68 of material for enhancing electron emission to the surface of the dispenser where it evaporates and is condensed on the electron emitters 66 and 61 which are heated to a materially lower temperature, say to about 800 C.
  • These ribbon or plate structures 66 and 61 which as indicated, may consist of wire gauze, are initially uncoated with oxide, the metal being clean and bright and yet becoming thermionically active without being visibly coated, indicating that the deposited activating material need be present only as an exceedingly thin and apparently monomolecular layer. Any appreciable coating which may accumulate slowly on these structures during life apparently is not necessary for the electron emission. Only a minute amount of material is vaporized from the dispenser. Hence, the dispenser has a long life.
  • the dispenser when of small diameter may be unprovided with a metal core. It is shown as being wound on an insulating support 19.
  • the dispenser 80 of the structure shown in these figures consists of a woven mesh of molyibdenum or the like which is filled with barium oxide or other suitable source material.
  • the sheath 8i and the filling 82 are shown in Fig. 9a, in which the sheath is shown partly cut away. The required heat is produced by current traversing the sheath from a source which has not been shown in order to simplify the drawings.
  • the electronemitting structures may consist of thin convolute sheet metal 83 on which is applied a woven wire structure 84 for increasing their area.
  • the structure 84 assists in holding in place the oxide or: other coating materials in those structures in which an oxide coating is applied to the emitting members. It serves to increase the electronemitting area in cathodes of the dispenser type in which no coating is applied to these members.
  • an electric discharge device the combination of an apertured heat-confining enclosure, an unshielded heater therein, one or more ribbon-shaped electron-emitting members located in said enclosure in a position to receive directly heat radiated by said heater and support means for said electron-emitting members, said means providing substantial heat insulation from contiguous heated parts.
  • an electric discharge device the combination of an elongated radiation heater, an electron-emitting ribbon consisting of thin material of low heat conductivity having provided thereon a material of high electron-emissivity, means for supporting said ribbon in unobstructed radiation-receiving relation to said heater, said supporting means being substantially thermally insulated from said heater, and a surrounding heat shield arranged and proportioned to effectively reflect and reradiate upon said ribbon heat received from said heater, whereby said ribbon may be uniformly heated to electron-emitting temperature.
  • an electric discharge device the combination of an elongated unshielded resistance heater, one or more electron-emitting ribbons of foil material arranged in unobstructed radiationreceiving relation to said heater, means having poor heat conductivity for supporting said ribbons, and means for reflecting heat radiation emanating from said heater upon said ribbons.
  • An electrical discharge device structure comprising the combination of an elongated resistance heater, a plurality of ribbons each having electrically activated surfaces of extensive area and edge surfaces of negligible area, means for supporting said ribbons about said heater in thermally non-conducting relation therewith, the ribbons being arranged to present only their said edge surfaces to the heater whereby they are substantially nonobstructive to heat radiated directly therefrom, and a housing enclosing the ribbons and constructed to reflect heat emanating from the heater upon the said activated surfaces.
  • a gas ionization discharge device the combination of a rod of refractory insulating material, an elongated radiation heater mounted thereon, a plurality of oxide-coated wire gauze members positioned radially about said heater. supports for said members mounted near the extremities of said heater, a thermally insulated enclosure having one or more apertures surrounding said members and being supported in unobstructed heat-receiving relation to said heater, said enclosure consisting of a plurality of laminae assembled in substantially heat-insulated relation to one another, and being proportioned to eiiectively reradiate heat received from said radiation heater, whereby said members are heated throughout to an electron-emitting energy ag' and means for supplying energy to said heater.
  • An assembly for an electric discharge device comprising the combination of a radiation heater, a spaced heat-conserving enclosure therefor having an aperture for the passage of a discharge.
  • one or more electron-emitting members located therein said enclosure and members both being positioned to receive heat by radiation directly from said heater, and support means for said members providing substantial insulation for heat conduction thereto, said emitting members being so constructed and so arranged within said enclosure that opposite surfaces can eflectively contribute electron emission for maintaining an electrical discharge emanating therefrom.
  • An assembly for an electrical discharge device comprising the combination of an apertured enclosure constructed to provide a steep, transverse heat gradient through the wall thereof, an unshielded filamentary radiation heater supported therein, conductors for supplying an energizing current to said heater, a plurality of electrically connected foil strips arranged about said heater in said enclosure and spaced from one another in position to be heated by direct heat radiations from said heater but not wholly shielding said enclosure from such radiation, said strips being provided with activating material for enhancing electron emission, support means for said strips arranged in non-heat-conveying relation to said heater, and a load circuit conductor connected to said strips.
  • An electrical discharge device comprising the combination of an envelope, a charge of attenuated gas therein, an anode, a cathode consisting of one or more electron-emitting ribbons, a separate heater therefor, said ribbons being coated with a material for enhancing thermionic electron emission, means aifording negligible heat conductivity supporting said cathode, a substantially insulated,
  • a gas ionization device the combination of an apertured heat-confining enclosure, an unshielded resistance heater of refractory metal located in said enclosure, a plurality of ribbon cathode elements arranged about said heater in said enclosure to present substantially only their edge surfaces to said heater, a material for enhancing thermionic electron emission of said ribbons, means for electrically connecting said elements to one another and support means for said cathode elements afiording negligible heat conductivity between said heater and said elements.

Landscapes

  • Electron Sources, Ion Sources (AREA)
  • Solid Thermionic Cathode (AREA)
  • Discharge Lamp (AREA)
  • Details Of Valves (AREA)
US243101A 1938-11-30 1938-11-30 Discharge tube electrode assembly Expired - Lifetime US2201731A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
US243101A US2201731A (en) 1938-11-30 1938-11-30 Discharge tube electrode assembly
US261395A US2201720A (en) 1938-11-30 1939-03-11 Thermionic cathode structure
US266803A US2246176A (en) 1938-11-30 1939-04-08 Thermionic discharge device
US283803A US2201721A (en) 1938-11-30 1939-07-11 Thermionic cathode structure
GB31133/39A GB536070A (en) 1938-11-30 1939-11-30 Improvements in and relating to thermionic discharge devices
FR861969D FR861969A (fr) 1938-11-30 1939-11-30 Perfectionnements aux dispositifs thermioniques à décharge
NL96091A NL55022C (fr) 1938-11-30 1939-11-30
FR51138D FR51138E (fr) 1938-11-30 1940-03-11 Perfectionnements aux dispositifs thermioniques à décharge
GB11440/40A GB542495A (en) 1938-11-30 1940-07-09 Improvements in thermionic cathode structures for electric discharge devices
BE438749D BE438749A (fr) 1938-11-30 1940-09-21

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US243101A US2201731A (en) 1938-11-30 1938-11-30 Discharge tube electrode assembly
US261395A US2201720A (en) 1938-11-30 1939-03-11 Thermionic cathode structure
US266803A US2246176A (en) 1938-11-30 1939-04-08 Thermionic discharge device
US283803A US2201721A (en) 1938-11-30 1939-07-11 Thermionic cathode structure

Publications (1)

Publication Number Publication Date
US2201731A true US2201731A (en) 1940-05-21

Family

ID=42358497

Family Applications (4)

Application Number Title Priority Date Filing Date
US243101A Expired - Lifetime US2201731A (en) 1938-11-30 1938-11-30 Discharge tube electrode assembly
US261395A Expired - Lifetime US2201720A (en) 1938-11-30 1939-03-11 Thermionic cathode structure
US266803A Expired - Lifetime US2246176A (en) 1938-11-30 1939-04-08 Thermionic discharge device
US283803A Expired - Lifetime US2201721A (en) 1938-11-30 1939-07-11 Thermionic cathode structure

Family Applications After (3)

Application Number Title Priority Date Filing Date
US261395A Expired - Lifetime US2201720A (en) 1938-11-30 1939-03-11 Thermionic cathode structure
US266803A Expired - Lifetime US2246176A (en) 1938-11-30 1939-04-08 Thermionic discharge device
US283803A Expired - Lifetime US2201721A (en) 1938-11-30 1939-07-11 Thermionic cathode structure

Country Status (5)

Country Link
US (4) US2201731A (fr)
BE (1) BE438749A (fr)
FR (2) FR861969A (fr)
GB (2) GB536070A (fr)
NL (1) NL55022C (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2610305A (en) * 1951-01-05 1952-09-09 Chatham Electronics Corp Control electrode for discharge tubes
US2647216A (en) * 1950-04-01 1953-07-28 Rca Corp Dispenser cathode

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE477491A (fr) * 1943-05-28
US2456649A (en) * 1943-06-12 1948-12-21 Glenn F Rouse Cathode
US2675498A (en) * 1948-12-07 1954-04-13 Raytheon Mfg Co Cathode for electron discharge devices
US2605432A (en) * 1949-10-19 1952-07-29 Electrons Inc Indirectly heated cathode structure
DE962188C (de) * 1951-10-12 1957-04-18 Philips Nv Elektrische Entladungsroehre mit Quecksilberkathode und Gasfuellung
DE1018164B (de) * 1952-12-04 1957-10-24 Siemens Ag Gasentladungsroehre
GB931059A (en) * 1961-02-10 1963-07-10 Thorn Electrical Ind Ltd Improvements in and relating to thermionic cathodes
NL141698B (nl) * 1964-12-10 1974-03-15 Philips Nv Indirect verhitte kathode voor een elektrische ontladingsbuis.
GB1204316A (en) * 1966-09-26 1970-09-03 Atomic Energy Authority Uk Improvements in or relating to electron emitting cathodes for irradiation machines
US3534218A (en) * 1967-03-30 1970-10-13 Atomic Energy Authority Uk Electron emitting cathodes for irradiation machines
US4611147A (en) * 1984-04-05 1986-09-09 The United States Of America As Represented By The United States Department Of Energy Thermionic gas switch

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2647216A (en) * 1950-04-01 1953-07-28 Rca Corp Dispenser cathode
US2610305A (en) * 1951-01-05 1952-09-09 Chatham Electronics Corp Control electrode for discharge tubes

Also Published As

Publication number Publication date
US2246176A (en) 1941-06-17
FR861969A (fr) 1941-02-22
NL55022C (fr) 1943-08-16
US2201721A (en) 1940-05-21
BE438749A (fr) 1940-10-31
GB536070A (en) 1941-05-01
FR51138E (fr) 1941-08-08
GB542495A (en) 1942-01-12
US2201720A (en) 1940-05-21

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