US3313973A - Multi-electrode cold-cathode discharge tube comprising ring magnet with attached electrodes - Google Patents

Multi-electrode cold-cathode discharge tube comprising ring magnet with attached electrodes Download PDF

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Publication number
US3313973A
US3313973A US282534A US28253463A US3313973A US 3313973 A US3313973 A US 3313973A US 282534 A US282534 A US 282534A US 28253463 A US28253463 A US 28253463A US 3313973 A US3313973 A US 3313973A
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electrodes
tube
cathode
discharge
electrode
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Expired - Lifetime
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US282534A
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English (en)
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Reaney Donald
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Ericsson Telephones Ltd
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Ericsson Telephones Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00—Gas-filled discharge tubes with solid cathode
    • H01J17/38—Cold-cathode tubes
    • H01J17/48—Cold-cathode tubes with more than one cathode or anode, e.g. sequence-discharge tube, counting tube, dekatron
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00—Discharge tubes and lamps
    • H01J2893/007—Sequential discharge tubes

Definitions

  • Cold-cathode discharge tubes are well known which comprise a single anode electrode surrounded by a ring of cathode electrodes, usually ten in number. Between each pair of adjacent cathode electrodes are two or three guide electrodes ,provided to enable a discharge between the anode and one cathode to be transferred to an adjacent cathode.
  • the guide electrodes are connected together to form common first guide, second guide, and possibly third guide connections, and the anode and each cathode is connected to a separate pin on the base of the tube.
  • Such tubes may be used for selecting, counting and other purposes and are sold under the Registered Trade Mark Dekatron.
  • a tube of the type described above depends upon the relative potentials applied to the invested cat-hode and adjacent guide electrodes.
  • the discharge is attracted away from a cathode by reducing the potential applied to an adjacent guide electrode below the potential of the cathode itself.
  • This operation by means of guide electrodes provides the tube with a particular determinable transfer characteristic. It is well known that during the operation of such a tube material is removed from the surface of the cathode electrodes by sputtering. A considerable proportion of the sputtered material is deposited on adjacent guide electrodes and changes the transfer characteristic of the tube. This is especially noticeable if the discharge is allowed to remain on one cathode for any length of time.
  • a multielectrode cold-cathode discharge tube in which a dis-- charge investing a first electrode and one of a plurality of second electrodes arranged equidistant from the first electrode is capable of movement from one to another of the second electrodes under the influence of a uniform deflecting field perpendicular to that existing between the two invested electrodes, and in which such movement may be prevented by the application of a locking potential to a similar plurality of intermediate electrodes located one between each pair of adjacent second electrodes.
  • the second and intermediate electrodes are arranged in a circle having the first electrode at its centre.
  • FIGURE 1 shows a sectional plan view of a tube according to one embodiment of the invention in which the deflecting field is provided by a cylindrical permanent magnet;
  • FIGURE 1a shows a modification of FIGURE 1 using an electromagnet
  • FIGURE 2 shows, diagrammatically, a method of connection of the tube of FIGURE 1;
  • FIGURE 3 shows a sectional plan view of a tube according to a further embodiment of the invention in which the deflecting field is an electrostatic field.
  • a discharge tube 10 comprises a cylindrical glass envelope 11 having a disc or rod-shaped cathode C mounted substantially at its centre.
  • ten anode electrodes A1 to A0 and ten locking electrodes L1 and L0 Arranged in a concentric circle are ten anode electrodes A1 to A0 and ten locking electrodes L1 and L0, arranged alternately as shown. These electrodes are normally all connected to separate pins in the base of the tube, though the ten locking electrodes may be connected together to a single pin.
  • the glass envelope is evacuated and filled with a hydrogen or hydrogen-inert gas mixture in known manner.
  • a cylindrical permanent magnet 12 which is magnetised so as to produce a magnetic field parallel to the axes of the electrodes.
  • the cathode electrode is connected through a resistor 13 to a source of negative potential of -500 volts.
  • Each anode is connected through a separate resistor 21 to 30 to earth potential.
  • Outputs S1 to S0 may be taken from the anode electrodes.
  • the ten locking electrodes are connected together either inside or outside the tube to a control circuit (not shown). This normally applies a locking potential of the order of -180 volts to the locking electrodes.
  • a discharge will form between the cathode and one anode electrode.
  • the magnetic field will tend to move the discharge around the tube in a direction depending upon the direction of the field, and this effect will be opposed by the electric field due to the locking potential.
  • the control circuit when triggered, applies a 30 volt positive pulse to the locking electrodes and thus reduce the locking potential to volts.
  • the discharge now moves around the tube to an adjacent anode electrode under the influence of the magnetic field.
  • the duration of the control pulse is such that the discharge is only allowed to move one step around the tube.
  • the discharge will rotate freely around the tube, moving from one anode to the next.
  • the freerunning speed depends upon several factors including the characteristics of the gas filling and the strengths of the electric and magnetic fields.
  • the strength and location of the magnetic field are not critical, though there is an upper limit to the magnetic field strength above which the locking electrode will be ineffective With the applied potentials as shown in FIGURE 2 and a cathode current of two milliamps the output potential on an invested anode will be about -10 volts.
  • FIG. 1a Although the above embodiment described the use of a cylindrical permanent magnet placed outside the envelope it is of course possible to place this magnet inside the envelope as shown in FIG. 1a.
  • the cylindrical magnet in either position may be replaced by two or more separate magnets suitably located and magnetised. If ceramic magnets are used it is possible to incorporate some or all of the electrodes with the magnets by the use of conductive coatings.
  • the permanent magnetic field may be replaced by an electromagnetic field, the electromagnet having a hollow cylindrical core of the same shape as magnet 12 and embraced by an energizing winding 31.
  • the direction of rotation may be reversed simply by reversing the energising current.
  • FIG- URE 3 it will be seen that the construction of the tube is very similar to that shown in FIGURE 1.
  • the external magnet has been removed and a concentric ring of bias electrodes B1 to B20 has been added outside the ring of anodes and locking electrodes.
  • the bias electrodes are located midway between each adjacent electrode already mentioned.
  • the bias electrodes are either connected to separate pins in the base of the tube or alternate bias electrodes may be connected together and two bias connections taken to pins.
  • the two sets of bias electrodes are connected to two sources of potential through a device which enables these two potentials to be readily reversed.
  • a bistable circuit is suitable for this purpose, one bias connection being connected to each of the outputs.
  • the potentials on the two sets of bias electrodes may be reversed by changing the state of the bistable device.
  • the electric fields set up between adjacent bias electrodes are substantially tangential to the circles of electrodes.
  • the discharge formed between the cathode and one anode will tend to move to an adjacent anode under the influence of the local electrostatic field. This movement is prevented by the locking potential applied to the looking electrodes. When it is desired to move the discharge the locking potential is removed or reduced for sufficient time for the discharge to move to the adjacent anode.
  • the direction of rotation of the discharge will depend upon the direction of the local electrostatic field.
  • the tube control circuit is arranged to reduce or remove the locking potential and change the state of the bistable bias circuit each time an input signal is received.
  • the potential applied to the first set of bias electrodes should be about 1( volts and that applied to the second set of bias electrodes should be about 50 volts.
  • the potentials applied to the various electrodes of the tube are only examples of suitable values, and other values may be used as required.
  • the anode line is main- 4 tained at earth potential to avoid the problem of insulating the output leads. It is of course possible to connect the cathode resistor to earth and to apply a positive potential of 500 volts to the anode line. The difference between these and the other potentials would be maintained.
  • the embodiments described above are ten position tubes with ten anodes and ten locking electrodes. It is possible to vary this number as required so long as there are equal numbers of anodes and locking electrodes. If bias electrodes are used the number of these should also be equal to twice the number of anodes.
  • Both of the embodiments described above incorporate a single cathode electrode and a plurality of anode electrodes.
  • a tube having a common anode and a plurality of cathodes will function in a similar way through the applied potentials will, of course, be different.
  • the electrodes are arranged parallel to each other, they may be arranged otherwise.
  • the outer electrodes may be arranged in the same plane pointing inwards towards the central electrode.
  • a multi-electrode cold-cathode gas-filled discharge tube which includes a first electrode and a plurality of second electrodes disposed equidistant therefrom so that a discharge may invest the first electrode and any one of the second electrodes, at least one permanent magnet located inside the envelope of the tube and arranged to apply a uniform magnetic deflection field at right angles to a discharge so that the discharge is thereby deflected from one to another of said second electrodes, and an intermediate electrode between each pair of second electrodes capable of being maintained at a locking potential whereby deflection of a discharge is prevented, each of said second and said intermediate electrodes being carried by said magnet.

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US282534A 1962-06-01 1963-05-20 Multi-electrode cold-cathode discharge tube comprising ring magnet with attached electrodes Expired - Lifetime US3313973A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB21131/62A GB980339A (en) 1962-06-01 1962-06-01 Multi-electrode cold-cathode discharge tube

Publications (1)

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US3313973A true US3313973A (en) 1967-04-11

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US (1) US3313973A (de)
CH (1) CH414874A (de)
GB (1) GB980339A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010151458A1 (en) * 2009-06-23 2010-12-29 L-3 Communications Corporation Magnetically insulated cold-cathode electron gun
CN103400735A (zh) * 2013-07-05 2013-11-20 广西全通电子技术有限公司 多电极触发型放电管及其放电方法

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB697602A (en) * 1948-06-10 1953-09-23 Ericsson Telefon Ab L M Gaseous discharge tube with arc discharge
US2846611A (en) * 1950-12-12 1958-08-05 Int Standard Electric Corp Electric discharge tubes and circuits therefor
US2999183A (en) * 1959-02-16 1961-09-05 Burroughs Corp Counting tube circuits
US3008067A (en) * 1959-07-02 1961-11-07 Burroughs Corp Counter circuit and count indicator
US3028520A (en) * 1960-07-13 1962-04-03 Burroughs Corp Pulse generator
US3085174A (en) * 1959-01-06 1963-04-09 Philips Corp Glow-discharge indicator tube
US3092752A (en) * 1960-05-23 1963-06-04 Burroughs Corp Drive circuit for electronic counters with means to prevent spurious switching
US3168674A (en) * 1960-03-08 1965-02-02 Burroughs Corp Magnetron beam tube circuit
US3226591A (en) * 1962-06-06 1965-12-28 Aerospace Corp Heavy duty gas tube with a magnetic trigger

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB697602A (en) * 1948-06-10 1953-09-23 Ericsson Telefon Ab L M Gaseous discharge tube with arc discharge
US2846611A (en) * 1950-12-12 1958-08-05 Int Standard Electric Corp Electric discharge tubes and circuits therefor
US3085174A (en) * 1959-01-06 1963-04-09 Philips Corp Glow-discharge indicator tube
US2999183A (en) * 1959-02-16 1961-09-05 Burroughs Corp Counting tube circuits
US3008067A (en) * 1959-07-02 1961-11-07 Burroughs Corp Counter circuit and count indicator
US3168674A (en) * 1960-03-08 1965-02-02 Burroughs Corp Magnetron beam tube circuit
US3092752A (en) * 1960-05-23 1963-06-04 Burroughs Corp Drive circuit for electronic counters with means to prevent spurious switching
US3028520A (en) * 1960-07-13 1962-04-03 Burroughs Corp Pulse generator
US3226591A (en) * 1962-06-06 1965-12-28 Aerospace Corp Heavy duty gas tube with a magnetic trigger

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010151458A1 (en) * 2009-06-23 2010-12-29 L-3 Communications Corporation Magnetically insulated cold-cathode electron gun
US8129910B2 (en) 2009-06-23 2012-03-06 L-3 Communications Corporation Magnetically insulated cold-cathode electron gun
CN103400735A (zh) * 2013-07-05 2013-11-20 广西全通电子技术有限公司 多电极触发型放电管及其放电方法
CN103400735B (zh) * 2013-07-05 2016-02-10 广西新全通电子技术有限公司 多电极触发型放电管及其放电方法

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GB980339A (en) 1965-01-13
CH414874A (de) 1966-06-15

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