US2190552A - Gas tube circuit - Google Patents

Description

Fel 13 1940. L. 'K. SWAN v 2,190,552

GAS TUBE CIRCUIT Filed July 3, 1936 Line INVENTOR .LE Savant C ATToRNEY I PatentedFeb. 13, 1940 UNITED STATE:

GAS TUBE CIRCUIT Leland Kasson Swart,

Mountain Lakes, N. J.,

, assignor to American Telephone and Telegraph Company, acorporation of New York Application July 3,1936, Serial N... 88,904

4 Claims.

This invention relates to gas-filled tubes and to circuits therefor. More particularly, this invention relates to arrangements for indicating nected to an input circuitand the third electrode' l and one of the other electrodes to an output or work-circuit. A source of voltage-generally a direct currentv'o1tage-may be connected to the work circuit, but this voltage must be less than the voltage required to ionize the gas between the electrodes to which the work circuit is connected, yet .be greater than the voltage required to sustain gaseous ionization between these electrodes after such'ioniration has been initiated. The work circuit of such an arrangement may "be actuated by applying tothe input electrodes a: voltage exceeding that required to initiate ionization between these input electrodes. However, if the source of voltage of the output circuit is of the alternating type, and of a peak voltage "26 less than the breakdown voltage between the electrodes'of the output circuit,.it is essential that gaseous ionization be initiated at, or that ionization bemaintained until a time when the peak voltage is applied to the output circuit "flfljelectrodes. 1 V

v "The objects and features of this invention will be better understood from the detailed descrip- "tion hereinafter following when read in 0011111801- 'tion" with the accompanying drawing which shows one embodiment of the invention merely for the purpose of illustration.

Referring to the drawing the primary winding of the transformer T is connected to a line or circuit which may or may not be used for sigto naling purposes." 'Ihe'secondarywinding of the "transformer is connected to the inputelectrodes 'G and K r a cold cathode gas-filled tube N,

the interconnected circuit includinga condenser C1 shunted by a resistor R1. The anode A of the tube'together with electrode (cathode) K form the output or work circuit electrodes. Besides the latter electrodes the output or work circuit includes an alternating current generator B, a resistor R2, relay W, all arranged in series relationship. The winding of relay W is shunted by a condenser C2.

The armature and make contact of relay W are connected between the electrodes A and K of tube Ni through the winding of relay W. Y The peak voltage of. generator B must be less a lamp L, and the winding of a than the breakdown voltage between theanode A and cathodeK. Were the generator of higher peakvoltage, gaseous io'nizationwithin tube 'N would be initiatedbetween electrodes A and K independently of the 1 presence or absence of voltage in the input circuit. l Voltages transmitted from the line through transformer T are transmitted through condenser C1 and resistor R1 which is of large magnitude, and then to the electrodes G and K ofthe tube N. If such voltage exceeds the breakdown voltage between these electrodes, gaseous ionization will be initiated. The generator B willthen I transmit current through resistorRz, lamp L,

the winding of relay w and through the path between electrodes A and K of tube N.

The relay W, which may bepart of recording equipment, will indicate thatsufilcient voltage a tube to ionize the gas therebetween. V I The voltage availabletto' operate therelay W (and its associated equipment) will depend upon the voltage difierencebetween the average voltage applied by generatorlB and the voltage re quired to sustainglow between the anode A and cathode K. The greater this voltage differ: ence-the upper limit of applied voltage always being less than the breakdown voltage between electrodes A ayid K-the moreqenergy may be available to operate relay W and its associated apparatus. The energy available is also related to the time that the voltage applied in the work circuit exceeds the sustaining, voltage of the tube.

In view of these limitations upon the energy f available in the work circuit-the necessary requirement that the breakdown voltage between A and K be very high with respect to the sustaining voltage-difliculty may beimet inoperation of circuits operated especially froma source of alternating current, unless thefeatures of this invention are employed.

Impulses of .very short, duration applied to the input circuit of the tube may occur at intervals when the voltage in the work circuit is belbw l. the sustaining voltage of the tube, but in the present invention, this will not hamperbperatio'n of the work circuit. The condenser C2 shunting the winding of relay W is employed to lengthen out the hold over time of this relay. Thi ablesthe relay operation to be accomplished when ionization voltage has been applied between V the input electrodes at a brief interval theretofore.

A The condenser C1 which has been appliedto the input electrodes; of the? shunts resistor Rt 55 and the sustaining voltage.

. trode tube.

stores a portion of the energy obtained through transformer T during the interval of time that the voltage applied between electrode G and cathode K exceeds the sustaining voltage between these electrodes. This same condenser C1 discharges from cathode K-to electrode G on disappearance of potential from the transformer T.

The presence of condenser C1 and shunt resistor R1 insures that. all impulses-no matter how short-if of proper magnitude will lock in the tube N for a period long enough to operate relay W. The addition of condenser C2 will also insure that generator B will pass current through the work circuit.

In order to further assurethe indication of the occurrence of short-lived impulses, the auxiliary electrode G should be made of very small area. In such an arrangement the impedance path from the auxiliary electrode Gto the cathode l iwill be but a few hundredohms, whereas the path from cathode K to electrode G will be of several thousand ohms. The discharge time between these electrodes will therefore be vastly in excess of that of the charging time of condenser C1. Hence glow'will persist between these electrodes for an interval of time suiiicient to lock in the work circuit.

, It is also desirable to employ inert gases at such pressures as to promote slow deionization of the gas within the tube N. This will lengthen out the period of deionization between electrodes G and K for a period of time necessary to enable operation of. the'work circuit.

Itis also important that the anode A of tube N be of small area, that is, practically point like in shape. The difiference between the areas of electrodes A and K determines in a large measure the difierence between the breakdown voltage The greater this difference, the greater will be the energy availablein the work circuit. b

. As the anode A becomes of smaller and smaller area and, approaches a point, more and more rectification of the alternating current supplied by generator B will take place. The condenser C2 of the work circuit aids in storing this rectified current so that it may be applied to the apparatus of the Work circuit while the voltage of source B passes through zero.

In the arrangement shown in the drawing, p-

eration of relayW will reduce to zero the voltage between electrodes A and K as a consequence of the closure of the circuit of the contact of the relay. This enables relay W to release and the gas within tube N to deionize and be prepared for another voltage surge at its input electrodes.

If desired the tube N may be replaced by a tube having four electrodes, two of which may be connected to thecircuit to which electrodes G and K is connected. The remaining two electrodes may be connectedto the circuit to which electrodes A and K is connected. Such an arrange ment may be caused to operate in the manner already described with respect to the three-electime interval.

While this invention has been shown and de scribed in a certain particular arrangement merely for the purpose of. illustration, it will be understood that the general principles of this invention may be applied to other and widely varied organizations without departing from the spirit of the invention and the scope of the appended claims.

What is claimed is:

l. The combination of an input circuit, a work circuit independent of said input circuit, and a gas tube having an electrode of large area and another electrode between which the input circuit is connected, said tube having a third, pointlike electrode which is connected to the electrode of large area through the work circuit, said input circuit including a condenser which, upon discharge, will maintain the gas within the tube ionized'for a predetermined time interval, the charging circuit of said condenser including the electrodes of said tube to is connected. 1

. 2. The combination of input and output circuits which are independent of each other, a gasfilled tube having three electrodes one of which ispcint-like, said input circuit including a condenser and being connected to. said point-like electrode and one cfthe other electrodes, said condenser being charged through a path formed by the two electrodes to which said condenser is connected only when voltages applied to the input circuit are sufiicient to produce ionization of the gas of the tube, said output circuit being connected to the two electrodes other than said point-like electrode, the discharge of. the condenser producing a voltage to maintain gaseous ionization within the tube for a predetermined 3. The combination of independent inputand output circuits, a condenser connected to said in put circuit, a gas-filled tube coupling both circuits, said tube having a plurality of electrodes one of which is point-like and connected to said input circuit but is notconnected to said output circuit, voltages applied to said input circuit .a predetermined time interval.

4. The combination of a gas-filled tube having at least three electrodes one of which is pointlike, a first circuit connected to the point-like which the input circuit electrode and one of the other electrodes, 2. sec- 0nd circuit connected to two of said electrodes neither of. which is said point-like electrodasaid first circuit including a condenser and means whereby a. predetermined voltage will charge, said condenser through a circuit including the electrodes of said first circuit and then .ionize the gas of the tube in one direction and upon disap pearance of said predetermined voltage will ionize the gas of the tube in the opposite direction for a predetermined time interval.

LELAND KASSON SWART.

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