US2097258A - Electron discharge tube - Google Patents

Electron discharge tube Download PDF

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Publication number
US2097258A
US2097258A US709082A US70908234A US2097258A US 2097258 A US2097258 A US 2097258A US 709082 A US709082 A US 709082A US 70908234 A US70908234 A US 70908234A US 2097258 A US2097258 A US 2097258A
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Prior art keywords
grid
tube
tubes
power
amplifiers
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Expired - Lifetime
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US709082A
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English (en)
Inventor
Sev Alexandre
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Thales SA
Original Assignee
CSF Compagnie Generale de Telegraphie sans Fil SA
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/26—Push-pull amplifiers; Phase-splitters therefor
    • H03F3/28—Push-pull amplifiers; Phase-splitters therefor with tubes only

Definitions

  • the present invention is concerned with power amplifiers used in public speaking, talking films, etc., and more particularly symmetric amplifiers known as of the push-pull pattern.
  • the present invention has as its object a high-power amplifier wherein the distortions due to power tubes connected push-pull fashion are practically obviated. It consists in a novel mode of coupling between the inputtube and the power tube next above it. This coupling method allows of eliminating the curved portion in characteristics of power tubes, while maintaining the output or efficiency at a high figure.
  • a further object of the invention is to provide a normal or fixed bias voltage to the grid of an amplifier tube and means whereby positive signal impulses also are impressed on the grid while-the negative signal impulses are substantially prevented from reaching the grid.
  • a still further object is to provide a vacuum tube construction in which a diode having an indirectly heated cathode and a triode having a heated filament are enclosed in the same glass envelope.
  • Figure 1 shows the curve of the plate current as a function of the potential of the grid or control electrode in a multi-electrode tube
  • Figure 2 shows the coupling of characteristics of a push-pull amplifier of class B, so-called
  • Figure 3 represents an embodiment of a coupling forming the object of this invention as applied to a push-pull amplifier
  • Figure 4 represents a different embodiment predicated upon the same principle
  • Figure 5 represents schematically a double tube adapted to operate in circuits as shown in Figures 3 and 4;
  • Figure 6 illustrates in a general way a mode of coupling as here disclosed.
  • the characteristic curve of Figure 1 comprises at its lower end a marked curvature or knee.
  • itis necessary to suppress the effects of the curvature Usually recourse is had to two methods, to wit:
  • the working point corresponds to a low permanent plate current and is usually located in the curved portion- (point B, Fig. 1).
  • point B point B, Fig. 1
  • two power tubes are connected symmetrically in phase opposition according to the conventional push-pull scheme.
  • Figure 2 shows the coupling of the characteristics of two tubes and by broken line the resultant characteristic.
  • the efiiciency may exceed 60 percent, but the compensation of the curved portions is often incomplete. Whence a distortion is present that will be especially appreciable where low powers are involved.
  • the method forming the object of the present invention consists in interposing between the input tube or previous stage and the grid of the power tube a circuit comprising an electronic valve, which will permit of the flow to the power grid only of the positive alternation of the potential wave.
  • the working point of the power tube is shifted just above the knee to point C, Fig. 1 by providing a suitable grid bias; and during actual operation it will be able to shift only towards the right-hand side, i. e., into a region where characteristics are sensibly rectilinear.
  • Fig. 3 represents an amplifier for telephone currents of the push-pull type.
  • the valves V1 and V2 are negatively biased by virtue of the fall of residual current in or across the resistances R, the value of which is chosen so as to render this current very small or a few microamperes.
  • V applied to the anode of V1 is positive
  • the variation of anode current 2' is practically proportional to V.
  • R is sufiiciently high the ohmic drop across the valve is negligible compared with V.
  • the positive alternation of V is transmitted to and impressed upon the control grid 4 of L1.
  • each of the tubes L1Lz is operative during an alternation.
  • the curved portions of the characteristics L1Lz are suppressed while yet preserving the advantages of amplifiers of class B.
  • the signal voltage is applied to the control grids by an audio transformer l2 whose primary coils are connected in the plate circuits of tubes it .and IL.
  • the fila-' ments of tubes L1L2 and the heaters 2 of V1 and V2 (whose cathodes 2 are indirectly heated) may be heated by alternating current supplied by a transformer IS.
  • the plate current of tubes L1L2 may be supplied by a battery or other voltage source l4 connected as shown, and their output may be connected to any translating device such as a loudspeaker I5.
  • FIG. 4 Another circuit scheme predicated upon the same principle is illustrated in Fig. 4.
  • the valve V1 connected in parallel with the grid of L1 keeps it at the potential of the common point C during the negative alternation of the voltage.
  • the internal resistance of V2 is infinitely high, and the positive alternation is transmitted and fed tothe grid of L2, etc.
  • valves with a high vacuum or else gaseous valves. It is also possible to substitute multi-electrode tubes for the valves, the characteristics of which present a suitable knee so as to insure a kind of operation as hereinbefore described.
  • a vacuum tube having an amplifier portion comprising a heatable filament, a grid and a plate, and a rectifier portion comprising a heater, a cathode and a plate, a single envelope enclosing all of the above named elements, connections within' the envelope between the filament terminals and the heater terminals and also between the grid and the rectifier cathode.
  • An electron discharge tube comprising an evacuated envelope enclosing a filamentary cathode, a grid next adjacent thereto and an anode constituting an amplifier, an indirectly heated cathode and an anode constituting a rectifier, and a direct electrical connection within the envelope between the indirectly heated cathode and the ALEXANDRE SEV.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Amplifiers (AREA)
US709082A 1933-02-09 1934-01-31 Electron discharge tube Expired - Lifetime US2097258A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR764491T 1933-02-09

Publications (1)

Publication Number Publication Date
US2097258A true US2097258A (en) 1937-10-26

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ID=9182166

Family Applications (1)

Application Number Title Priority Date Filing Date
US709082A Expired - Lifetime US2097258A (en) 1933-02-09 1934-01-31 Electron discharge tube

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US (1) US2097258A (cs)
BE (1) BE401208A (cs)
FR (1) FR764491A (cs)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2922059A (en) * 1955-10-14 1960-01-19 Columbia Broadcasting Syst Inc Amplifier tube

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2922059A (en) * 1955-10-14 1960-01-19 Columbia Broadcasting Syst Inc Amplifier tube

Also Published As

Publication number Publication date
BE401208A (cs)
FR764491A (fr) 1934-05-22

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