US2213762A - Electron discharge tube - Google Patents

Electron discharge tube Download PDF

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Publication number
US2213762A
US2213762A US203419A US20341938A US2213762A US 2213762 A US2213762 A US 2213762A US 203419 A US203419 A US 203419A US 20341938 A US20341938 A US 20341938A US 2213762 A US2213762 A US 2213762A
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US
United States
Prior art keywords
cathode
grid
emission
electron discharge
discharge tube
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
US203419A
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English (en)
Inventor
Flechsig Werner
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.)
FIRM FERNSEH AG
Original Assignee
FIRM FERNSEH AG
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 FIRM FERNSEH AG filed Critical FIRM FERNSEH AG
Application granted granted Critical
Publication of US2213762A publication Critical patent/US2213762A/en
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
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/26—Image pick-up tubes having an input of visible light and electric output
    • H01J31/28—Image pick-up tubes having an input of visible light and electric output with electron ray scanning the image screen
    • H01J31/30—Image pick-up tubes having an input of visible light and electric output with electron ray scanning the image screen having regulation of screen potential at anode potential, e.g. iconoscope
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J43/00—Secondary-emission tubes; Electron-multiplier tubes
    • H01J43/04—Electron multipliers
    • H01J43/30—Circuit arrangements not adapted to a particular application of the tube and not otherwise provided for

Definitions

  • This invention relates to electron discharge tubes, employing thermionic emission, which are operated in the region of the characteristics in wh ch a retarding field action upon the electron emission is exerted.
  • the difiiculty arises that the emitted current is highly dependent upon the temperature of the cathode, that is, upon variations in the filament heating power. This is particularly true of grid-controlled amplifier tubes, operated in the retarding-field region, in which the emission from the cathode is subjected to one or repeated processes of electron multiplication after passing through the control grid. Measurements show that a 10% variation of the heating power results in doubling, or halving, of the current in the retarding-field region.
  • This method may also be readily applied in the case of control in the retarding-field region in order to maintain a constant average cathode emission for varying heating power. Because the grid current represents a considerable portion of the tota1 emission, if the tube possesses high mutual conductance in the retarding-field region, a sufiiciently large grid-leak resistance may fulfill the same purpose in this case.
  • the tube characteristics in the retarding-field region follow exponential curves, and diificulties arise if large control amplitudes are applied. The curvature of the characteristics causes a rectifier effect, which largely displaces the automatically adjusted operating point. Amplitudes of only volt are to be considered large in this respect.
  • Variations in the amplitude of the control Voltage would consequently lead to variations in the gain of the tube. Increases in amplitude having a duration shorter than the time constant'of the circuit components in the cathode lead would be amplified without displacement of the operating point. However, increases in amplitude of greater duration would lead to a displacement of the operating point, resulting in smaller gain.
  • This invention provides for substantially maintaining the position of the operating point in such cases also, without disturbing the described compensation for variations in cathode temperature.
  • the minor portion of the cathode emission is subjected to grid control, while the major portion is not modulated and is collected by an auxiliary electrode which is connected with the cathode through a resistor.
  • a negative grid bias is produced across this resistor which increases with increasing cathode current.
  • This resistor is shunted by a condenser in the known manner.
  • a greater amplitude of control Voltage causes the average emission flowing towards the control grid to increase. However, this now causes only a negligible increase in total emission current. Thus, the point of operation remains in substantially the same position. If, however, a variation in cathode temperature occurs, the entire emission current is varied so that the operating point adjusts itself to the correct position.
  • Thedrawing shows an embodiment of the invention.
  • the unipotential cathode l is indirectly heated by a filament, not shown.
  • the current emitted by the middle portion of the cathode alone is subjected to grid control.
  • the cathode is surrounded by control grid 2.
  • the remaining (by, for instance, 80% or more) greater portion of the cathode is surrounded by two symmetrically arranged cylindrical electrodes 3 and 4, which are 'conductively connected to each other. connected to the cathode I through a parallel network 5 consisting of a resistor and a condenser, across which the grid bias is produced in the described manner.
  • a grid-leak resistor 6 which is sodimensioned that no substantial voltage drop is produced across it.
  • the control voltage is applied to the grid through a condenser l.
  • the elements of the electron discharge tube are housed in a vacuum receptacle, as shown at 8.
  • an electron discharge tube comprising a cathode, a pair of cylindrical auxiliary electrodes disposed about the end portions of said cathode and exposing an intermediate portion of said cathode, a grid-like auxiliary electrode disposed about said intermediate portion only, means including a resistor external to said tube for connecting said cylindrical auxiliary electrodes to said cathode, and a separate circuit for applying signals to said grid-like auX- iliary electrode.
  • the cylinders 3 and 4 are"

Landscapes

  • Circuit Arrangements For Discharge Lamps (AREA)
  • Electrodes For Cathode-Ray Tubes (AREA)
US203419A 1937-05-01 1938-04-21 Electron discharge tube Expired - Lifetime US2213762A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEF82946D DE682158C (de) 1937-05-01 1937-05-01 Im Anlaufgebiet arbeitende gittergesteuerte Entladungsroehre

Publications (1)

Publication Number Publication Date
US2213762A true US2213762A (en) 1940-09-03

Family

ID=7990442

Family Applications (1)

Application Number Title Priority Date Filing Date
US203419A Expired - Lifetime US2213762A (en) 1937-05-01 1938-04-21 Electron discharge tube

Country Status (4)

Country Link
US (1) US2213762A (de)
DE (1) DE682158C (de)
FR (2) FR829762A (de)
NL (1) NL62763C (de)

Also Published As

Publication number Publication date
NL62763C (de) 1949-04-15
DE682158C (de) 1939-10-09
FR829762A (fr) 1938-07-05
FR49427E (fr) 1939-03-24

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