US2871408A - Electronic counter - Google Patents

Description

Jan. 27, 1959 J. R. DESCH ELECTRONIC COUNTER 2 Sheets-Sheet 1 Filed April 21. 1953 PIC-3.2

INVENTOR JOSEPH R. DESCH BY 4a AL HIS ATTORNEYS Jan. 27, 19.59 J. R. DESCH 2,871,403

ELECTRONIC COUNTER FilOd April 21. 1955 2 Sheets-Sheet 2 I45 OR INVENT JOSEPH R. DESGH HIS ATTORNEYS United States Patent 9 ELECTRONIC COUNTER Joseph R. Desch, Dayton, Ohio, assignor to The National Cash Register Company, Dayton, Ohio, a corporation of Maryland Application April 21, 1953, Serial No. 350,133

10 Claims. (Cl. 315 84.5)

This invention relates to novel electron tube counting circuits and in particular relates to circuits employing cold-cathode gas tubes connected in a ring or chain for sequential operation one after another in response to'input impulses and employing blow-out electron tube means external to the ring or chain for causing a previously conducting tube of the chain to be extinguished whenever another tube in the chain is rendered conducting.

The principal advantages of the novel counting circuits lie in their simplicity and in the reliability of their operation, the external extinguishing circuits insuring proper and rapid blow-out of the cold-cathode gas tubes of the ring or chain as counting progresses.

Briefly, the novel ring or chain circuit utilizes coldcathode tubes of the type having at least an anode, a cathode, an igniter electrode, and a probe electrode. In these tubes, the igniter and the cathode form a starter gap by which ionization can be induced in a tube, and the anode and the cathode form the main gap, to which ionization spreads when the tube is operating. The tubes of the ring or chain are divided into two operational groups, with the cathodes of the-tubes of each group being connected together and to ground over connections which include a resistor which is common to the group, and with the anodes each group connected together and over a resistor, which is common to the group, to a source of anode potential.

The tubes, which are positive-grid tubes, are connected into an operative chain by floating connections between the tubes, which connections extend from the probe of a tube of one group to the igniter of a tube of the other group. In case of a ring, the probe of the last tube, which is in one group, is connected to the igniter of the first tube, which is in the other group. These floating connections are simple direct connections, which contain no impedance elements and have no additional connections to potential sources. They cause the sequential operation of the tubes to take place in the desired order by enabling the probe electrode in a conducting tube to so influence the igniter in the starting gap of' the next tube in the sequence that the starting gap will be primed to prepare the next tube so that it will conduct when the next input impulse is received on the cathodes.

The stepping of the conducting condition of the tubes of the ring or chain is obtained by applying negative potential input impulses to the cathodes of the tubes, that tube firing whose igniter is connected to the probe of a conducting tube of the chain and is primed by the conduction in that tube.

An additional extinguishing or blow-out tube is provided for each of the groups of the chain to cause a previously-conducting tube of the chain to be'extinguished each time the next tube in the chain is rendered conducting. Each blow-out tube has its anode connected ice ever a tube in one group begins to conduct, it will send an impulse to the blow-out tube related to the other group which causes that tube to operate and reduce the potential across the previously conducting tube of the other group thereby extinguishing the previously con ducting tube. The two blow-out tubes, accordingly, serve to blow-out any of the tubes of the ring.

The use of separate blow-out tubes removes the blow out function from the tubes of the ring or chain so that no provision need be made in 'thering circuits, per se, for causing other tubes to be extinguished. The separate blow-out tubes and their related circuits enable strong blow-out impulses to be obtained which can be made strong enough to insure that the cold-cathode tubes of the ring will be completely de-ionized as stepping progresses around the ring.

It is an object of the invention, therefore, to provide a simplified electron'tube counting circuit with separate blow-out tube means for blowing out or extinguishing previously conducting tubes as new tubes become conducting. i

A further object of the invention is to provide blowout means external to the ring for producing strong blowout impulses which will insure that any previously conducting tube of the ring Will be extinguished as a new tube is rendered conducting.

With these and other incidental objects in view, the invention includes certain novel features of construction and arrangement of parts shown in the several embodiments which are hereinafter described with reference to the drawings which accompany and form a part of this specification.

Of the drawings:

Fig. 1 is a circuit diagram of one embodiment of the invention in which the blow-outtubes are thyratrons having their anodes connected directly to the anodes of their related groups of tubes of the ring.

Fig. 2 is a perspective view of one of the cold-cathode tubes which make up the ring of tubes, showing in particular the shape and relative position of the several electrodes in the tube.

Fig. 3 is a circuit diagram of another embodiment of the invention in which the blow-out tubes are high vacuum tubes having their anodes connected to a higher anode potential than the tubes of the groups and having their anodes also coupled to the anodes of the tubes of their related groups to impress'negative blow-out impulses thereon.

Fig. 4 is a circuit diagram of another embodiment of the invention in which the blow out tubes are high vacuum tubes operated by impulses from the anodes of the tubes of the groups and supplying positive blow-out impulses to the cathodes of the tubes of the groups.

Detail description with dilierent numbers of tubes in the ring, the only limi-.

tation being that, when connected to operate as a ring, an even number of tubes must be provided. It will also become obvious from the following description that additional tubes can be included in the ring circuit without requiring any additional circuit elements of resistance or capacitance.

In the following description, values of potential with reference to ground and values of resistance and capacitance, as well as tube types, will be given. It is not intended that the invention be limited to these particular potentials or to the values of resistance specified herein, because the potentials used are merely selected as convenient potentials for the disclosure, and the values of the circuit elements of resistance and capacitance given correspond in relative value to the potentials chosen. It is also obvious that other types of tubes may be used and also that other potentials may be used, and, when this occurs, the values of the circuit elements can be adjusted accordingly to maintain the proper relationship between the various parts of the circuit.

Excellent results have been obtained from circuits constructcd according to the invention, using values of reslstance, capacitance, and potentials to be given. These circuits also show good tolerance to variations in the positive potential supply and in the size of input impulses which were supplied thereto.

In order to simplify the showing of the circuits, only the 0, 1, 2, 7, 8, and 9, digit-representing tubes of the rings have been shown, because the circuits and operation of the 3 to 6 digit-representing tubes are the same as those shown and will be clear from those circuits which are shown.

As shown in Fig. 1, the counting ring is made up of cold-cathode tubes. These tubes are of the type shown more fully in Fig. 2. A

The tube is provided with a plurality of electrodes, including, in order, a cathode, K; two igniters, I and I two further electrodes, one of which may be considered as a probe, P, and the other may be considered as an auxiliary anode, A and an anode, A.

The cathode K, which is a substantially round fiat disc about .75 of an inch in diameter, is made of a sheet 19 of magnesium and a sheet 20 of nickel, which are mounted on a support with the magnesium sheet facing the anode. The two sheets are fastened together at the support but are merely clipped together by a clip 21 at a point remote from the support to allow relative movement and prevent buckling due to the different coeflicients of expansion of the two metals.

Adjacent the cathode are the two igniter electrodes, which are made of .02 of an inch nickel wire. Igniter I which extends across the cathode parallel thereto and is spaced about .032 of an inch therefrom, can cooperate with the cathode to form a starting gap. lgniter 1 also extends across the cathode, parallel thereto, but runs approximately at right angles to igniter I and is spaced about .075 of an inch from the cathode. The igniter L, can be used with either the cathode or the igniter I to form a starting gap.

The probe P is a flat annular member made from sheet magnesium. Its outside diameter is substantially the same as that of the cathode, and it is mounted parallel to the cathode about .16 of an inch therefrom. This probe lies adjacent the anode-cathode discharge path and can be influenced greatly by a discharge in the tube.

The auxiliary anode A also is made of .02 of an inch nickel wire. is curved to generally follow the shape of the probe P, lies between the probe and the anode A, and also can be influenced by discharge in the tube.

The anode A is a disc of nickel about .25 of an inch in diameter. It is mounted on a suitable support parallel to the probe and about .16 of an inch therefrom.

The supports for the various electrodes are insulated and extend through a press 22 at the bottom of the tube.

' This tube was activated by pulse bombardment'of the cathode and the probe and is filled with argon gas at a pressure of 12 millimeters of mercury.

This type of tube has excellent operating characteristics and is very flexible in its use, since the several electrodes intermediate the anode and the cathode can be used in a variety of ways as igniters, as auxiliary cathodes, or as 4 probes, as required in the circuit in which the tube is to be used.

A tube constructed as above will have a striking potential from igniter I to cathode K of about volts; from igniter T to cathode K of about volts; from probe P to cathode K of about 180 volts; and from anode A to cathode K of about 300 volts. With the tube conducting and passing 5 milliamperes, it has a drop of about 67 volts from the cathode to either igniter 1 or 1 and a drop of about 75 volts from the cathode K to the anode A, and the probe P will be about 60 volts more positive than the cathode.

As shown in Fig. 1, the even tubes of the ring are connected to form a group by having their anodes connected together 'over conductor 23 and thence over resister 24 of 10,000 ohms to the tap 25 of a 10,000 ohm potentiometer 26 which is connected between the +420 volt terminal 27 and ground and by having their cathodes connected together over conductor 28 and to ground over resistor 29 of 22,000 ohms, point 30 and resistor 31 of 6800 ohms. 1

Similarly the odd tubes of the ring are connected to form a group by having their anodes connected together over a conductor 35 and thence over a resistor 36 of 10,000 ohms to the tap 25 of the potentiometer, and by having their cathodes connected together over conductor 37 and to ground over resistor 38 of 22,000 ohms, point 39 and resistor 40 of 6800 ohms.

The tap 25 which is coupled to ground over an 8 microfarad stabilizer capacitor is adjusted to provide the two groups of tubes with anode potential of about to volts.

The chain connections between the tubes extend from the probe of one tube to the igniter I of the next tube in the series; for example, from the probe of the 0 tube to the igniter I of the 1 tube; from the probe of the 1 tube to the igniter I of the 2 tube, etc. These connections, which are shown at 41, are direct wire connections which contain no impedance elements and are floating, since they have no direct connection with any potential source.

It is to be noted that the chain connections extend from the probe of a tube in one group to the igniter 1 of a tube in the other group, that is, the probe of a tube in the even group is connected to the igniter 1 of the next higher digit value tube in the odd group and the probe of a tube in'the odd group is connected to the igniter 1 of the next higher digit tube value in the even group. When the digit-representing tubes are connected to form a ring, as shown in Fig. l, the probe of the 9 tube is connected over a conductor 50 to the igniter I of the 0 tube.

These chain connections enable the tubes to be primed in succession so that they will operate one after another in response to negative input impulses applied to the cathodes of the tubes. For example, if the 0 tube is conducting, the probe of the 0 tube is in the ionized medium of the conducting tube and will make the igniter I of the 1 tube more positive. Since the tube is the only tube which is conducting in the ring, the igniter 1 of the 1 tube will be more positive than the similar igniter of any of the other tubes and the 1 tube will fire when a negative input impulse is applied to the cathodes of all the tubes. Such a counter chain compris ing a plurality of serially-connected digit-representing tubes is essentially the same as that disclosed in applicants co-pending application Serial No. 259,857, new Patent No. 2,644,112, filed December 4, 1951, issued June 30, 1953, and assigned to the present assignee of the instant application; however, the above-referred-to application utilizes an entirely different concept and circuit for bringing about the sequential operation of the chain from that of the instant invention, as will be fully described hereinafter.

Negative input impulses of any value between 250 and '400 volts are applied to the counting circuit at terminal 42 which is coupled to the cathodes of the two groups of tubes of the ring over the following circuit which extends from terminal 42 over point 43, capacitor 44 of .02 microfarad, and point 45 in the cathode circuit of a twin diode 46 of the 61-16 type. Point 43 in this circuit is coupled to ground over a resistor 47 of 220,000 ohms. The cathodes of the diode 46 are connected together and to ground over point 45 and resistor 48 of 220,000 ohms and capacitor 49 of .003 microfarad in parallel and the anodes of the diodes are coupled to points and 39 in the cathode circuits of the two groups of tubes of the ring. The diode 46 in the input circuit decouples the two cathode circuits of the ring to enable them to be used more efliciently in controlling the blowout tubes.

A separate blow-out tube is provided for each group of tubes of the ring. These blow-out tubes are thyratrons of the 2050 type and are connected in self-extinguishing circuits by which they Will be extinguished automatically shortly after they have been fired. The circuits for tube 55 which is the blow-out tube associated with the even group of tubes are representative of the circuits for both blow-out tubes and are as follows. The blow-out tube 55 has its anode directly connected to the conductor 23 which connects the'anodes of the even tubes together, has its cathode connected to ground over a resistor 56 of 330,000 ohms and capacitor 57 of .1 microfarad in parallel and has its control grid and shield grid connected together and connected over a resistor 58 of 22,000 ohms to point 59 which is connected to a -27 volt bias potential over a resistor 60 of 250,000 ohms and is coupled over a capacitor 61 of .0005 microfarad to the conductor 37 which connects the cathodes of the odd tubes together. Similarly, the blow-out tube 62 for the odd group has its anode connected to the conductor which connects the anodes of the odd group of tubes together and has its shield and control grids coupled to the conductor 28 which connects the cathodes of the even tubes together.

The operation of the blow-out tubes can best be understood by considering the operation of the tube 55 in extinguishing one of the even group of tubes when an odd tube is fired. With an even tube, say the 0 tube conducting, its cathode, as well as the cathodes of all even tubes which are connected thereto will be more positive than the potential of the cathodes of the odd tubes. Conduction in the 0 tube will cause the igniter 1;, of the 1 tube to be more positive than the igniters of the other odd tubes so that when a negative impulse is impressed on all the cathodes, the 1 tube will fire. As the 1 tube fires its cathode potential will rise sharply and this rise will be impressed over capacitor 61, on the grids of blow-out tube 55 and will fire this tube. At the moment tube 55 is fired, its cathode potential will be held at ground while capacitor 57 is charging and during this time its anode potential will drop and Will be positive by only the amount of the drop across the tube. Since the anode of the blow-out tube is directly connected to the anodes of the even group of tubes, the anodes of the tubes of this group will drop a similar extent and will be less positive than their cathodes which are at their higher potential due to conduction in the 0 tube and will cause conduction to cease in any tube of the group. As soon as the capacitor 57 has been charged, the anode potentials of the even tubes begin to rise and when the blow-out tube has been extinguished they Will be back to operating values so that the next even tube, the 2 tube, can operate in response to the next input impulse. In a similar manner, the firing of the 2 tube will fire the blow-out tube 62 and cause its anode potential and that of the odd" tubes to drop below cathode potential and extinguish the 1 tube.

The separate blow-out tube for each of the groups-of tubes of the ring has the advantage that blow-out capacito tors can be eliminated from the circuits of the various tubes of the ring and also has the further advantage that stronger blow-out impulses can be had to insure that the cold cathode tubes will be extinguished.

It the ring is to produce an output impulse each time a certain tube therein operates, as when the counting circuit forms one order of an accumulator, then the ring must cause the operation of an output tube. The output tube 65, which is a thyratron of the 2050 type, is connected in a circuit which will cause the tube to be extinguished automatically after it has been fired. The tube 65 has its anode connected over a resistor 66, of 250,000 ohms, to the +420-volt terminal 27; has its cathode connected to ground over point 67, resistor 68, of 470,000 ohms, and capacitor 69, of .01 microfarad, in parallel; and has its shield grid and control grid connected together and over resistor 70, of 100,000 ohms, to point 71, which is connected over resistor 72, of 220,000 ohms, to the 6- volt bias supply terminal 73, and is coupled over capacitor 74, of 50 micro-microfarads, point 75, and conductor 76 to the probe of the 0 tube, from which an impulse is received each time the 0 tube conducts. Point in this circuit is connected to ground over a resistor 77, of 4.7 megohms. The impulse from the probe of the 0 tube will cause tube 65 to fire and conduct momentarily, which causes a positive output impulse to be sent out from point 67 in the cathode circuit for tube 65 over a switch 78 and a capacitor 79, of .003 microfarad. The switch 753 is provided to prevent output impulses from being sent from the tube 65, as when the counting circuit is initially preset to Zero by causing the 0 tube to conduct.

The operation of the counting circuit is as follows. In orderthat the sequential operation of the tubes of the ring can take place, one of the tubes of the ring must be made conducting to provide the prime for the next tube to be operated. Any suitable means may be provided for this purpose, one such means being shown in Fig. 1 and consisting of a capacitor 62 of .0005 microfarad having one plate connected to the +420 volt terminal 27 and having the other plate connected to a conductor 63. After having discharged the capacitor by touching the conductor 63 to the terminal 27, the conductor is then momentarily connected to the igniter I of the desired tube of the ring. This will cause the tube to conduct and prime the next tube of the chain for response to an input impulse. If the 0 tube is the one that is thus fired to prepare the ring for operation, the switch 77 in the output circuit can be opened to prevent a spurious output signal from being sent from the circuit.

Considering that the 0 tube has been fired to prepare the ring for operation, its cathode will have become more positive due to conduction in the tube, and since the other even cathodes are connected to the cathode of the 0 tube, they too will be more positive so that a negative input impulse applied to the cathodes of the even tubes will be ineffective to cause them to fire.

Of the odd tubes only the 1 tube will have its igniter I connected to the probe of a conducting tube, the 0 tube. This will prime the 1 tube and make it more susceptible to fire when the negative impulse is applied to the odd cathodes.

When the 1 tube is fired, its cathode potential rise will fire the blow-out tube 55 which will cause the anode potential of the even tubes to drop to a value', relative to the potential of the cathodes, which will not support conduction in the even tubes and will thus extinguish the 0 tube.

The next impulse willfire the 2 tube which will cause the blow-out tube 62 to fire and extinguish the 1 tube.

Additional input impulses will cause the other tubes of the ring to become conducting one after another, the 9 tube priming the 0 tube to enable the sequential firing of the tubes to be continued.

Each time the 0 tube is fired and conducts, the potential rise ofits probe will be impressed as an impulse on 2,s71,4.os

the output tube 65 which operates and generates an output impulse.

The embodiment of the invention shown in Fig. 3 is similar to the one shown in Pig. 1, differing therefrom in the particular blow-out tube circuits and input circuits which are used.

The even tubes of the ring have their anodes connected together by conductor 04 and over a resistor 85 of 22,000 ohms to the tap of a 10,000 ohm potentiometer 86 which is connected between 9. +420 volt terminal and ground and are supplied with a potential of about +150 volts therefrom. The cathodes of the even" tubes are connected together by conductor 87 thence over a resistor 33 of 15,000 ohms to one of the anodes of a twin diode 3? of the 6H6 type whose cathodes are connected together and to ground over a resistor of 6800 ohms and a capacitor 91 of .001 microfarad in parallel.

Similarly the anodes of the odd tubes of the ring are connected together by conductor 92 and are connected over a resistor 93 of 22,000 ohms to the tap on the potentiometer S6, and the cathodes of the odd tubes are connected together by conductor 94 which is connected over a resistor 95 of 15,000 ohms to the other anode of the twin diode 89.

The tubes of the two groups are connected in a ring, probe to igniter 1 as in Fig. 1 to enable their sequential operation in response to input impulses.

Negative input impulses of from 250 to 500 volts can be applied to the cathodes of the diodes from input terminal 06 over point 97 and capacitor 08 of .02 rnicrofarad, point 97 being connected to ground over a resistor 99 of 220,000 ohms.

As in the counting circuit of Fig. 1, the stepping of the ring of Fig. 3 will take place as negative impulses are impressed on the cathodes of the tubes, via their respective halves of the diode 59.

In Fig. 3 the blow-out tubes 105 and 106 are high vacuum pentodes of the 6L6 type having their anodes connected over points 107 and 108 and resistors 109 and 110 of 150,000 ohms respectively to the +420 volt terminal and also connected to ground over .005 microfarad capacitors 111 and 112, and having their cathodes grounded. Point 107 in the anode circuit for tube 105 is coupled over a .03 microfarad capacitor 113 to the conductor 34 which connects the anodes of the even tubes together; and point 108 is similarly coupled over a capacitor 114 to the conductor 92 which connects the anodes of odd tubes together.

Tube 105 has its control grid connected over resistor 115, of 250,000 ohms, to the 55-vo1t bias supply terminal 116, and coupled over a capacitor 117, of .005 microfarad, to the conductor 94, which connects the odd cathodes together. Similarly, the control grid of the blow-out tube 106 is connected to the bias supply terminal T116 and is coupled to the conductor 87, which connects the cathodes of the even tubes together. Due to the bias supplied to the control grids, tubes 105 and 106 are normally non-conducting.

The operation of the counting ring of Fig. 3 is similar to that of Fig. 1. The ring may be preset with any tube conducting by using a capacitor, as 61 in Fig. 1, dischar ing the capacitor, and then touching the free lead to the igniter I, of any tube to cause that tube to conduct and prime the next tube in the ring for response to input impulses.

Each negative input impulse will cause the primed tube of the ring to conduct, and the act of conduction in the tube will cause its cathode potential to rise to a positive value which will be applied as a positive impulse to the control grid of the related blow-out tube to cause it to conduct. Since the blow-out tubes have +420 volts applied to their anodes and have their cathodes grounded, conduction in one of these tubes will cause a large negative excursion of the anode potential, which is applied through capacitors HB'and 1'14, as the case may be, as

8 a negative impulse to the anodes of the tubes of the group which contained the previously-conducting tube and will drive the anode potential ofthis group below the potential of their cathodes and cause the previously conducting tube to be extinguished.

The particular advantage of this blow-out tube arrangement lies in the fact that by using much higher anode potential for the blow-out tubes than that used for the tubes of the ring, much larger blow-out impulses can be obtained to insure that any previously conducting tube of the ring will be extinguished.

An output tube 118 similar to the one used with the circuit of Fig. 1 is provided and is controlled from the probe of the 0 tube to produce an output impulse each time the 0 tube is fired. The circuit constants of the output circuit are the same as those for the output circuit of Fig. 1 except that a bias of 22.5 volts is supplied to the control grid.

A further embodiment of the invention is shown in Pig. 4. In this embodiment, each blow-out tube is controlled from the anodes of the tubes of one of the groups and applies positive blow-out impulses to the cathodes of the tubes of the other group.

As in the other embodiments, the even tubes of the ring have their anodes connected together by conductor .121 and over a resistor 122 of 10,000 ohms to the tap of a 10,000 ohm potentiometer 1123 which is connected between the +420 volt terminal 124 and ground; and the odd tubes of the ring have their anodes connected together by conductor 125 and over resistor 126- of 10,000 ohms to the tap on potentiometer 123. The anodes of both sets are supplied with a potential of about +150 volts over their respective circuits from the tap on the potentiometer.

The cathodes of the even tubes are connected together by a conductor 127 and to ground over resistor 12% of 22,000 ohms, point 129 and resistor 130 of 10,000 ohms and the cathodes of the odd tubes are connected together by a conductor 131 and to ground over resistor 132 of 22,000 ohms, point 129 and the resistor 1.30 which is common to the two groups of cathodes.

As in the counting circuits of Figs. 1 and 3, the tubes of the ring are connected, probe-to-igniter I in series, which series connections enable conduction in a tube of the ring to prime the next tube for response to the next input impulse.

Negative potential input impulses are applied to the cathodes of the ring from terminal 133 over point 134 and capacitor 135 of .05 microfarad to common point 29 in the cathode resistor network, point 134 being connected to ground over a resistor 136 of 220,000 ohms. Tie input impulses will cause the primed tubes of the ring to fire and become conducting one after another, thereby producing step-by-step operation of the tubes of the ring.

Blow-out tubes 1140 and 141, which are high vacuum tubes of the 6L6 type, are utilized to supply blow-out impulses to the ring. Tube 140 has its anode and screen grid connected over point 142 and resistor M3 to the +420 volt terminal 124 and has its suppressor grid and cathode directly connected to ground. Point 1 12 in the anode circuit of tube 140 is coupled over a capacitor 144 of .03 microfarad to the conductor 127 which connects the cathodes of the even tubes together.

The control grid of tube 140 is connected to a -16 volt terminal over a resistor 145 of 250,000 ohms and is supplied with -12.5 volts therefrom and is also connected to the anode of a diode which is half of a tube 146 of the 6H6 type. The related cathode of the diode is connected to ground over a resistor 147 of 470,000 ohms and is coupled over a capacitor 148 of .005 microfarad to the conductor 125 which connects the anodes of the odd tubes together.

Tube 140 normally is conducting but when an odd tube is fired, its anode potential drop is impressed across the diode, on the control grid of tube 140 to decrease conduction therein. The anode potential rise, due to decreased conduction in tube 140 is impressed, as a positive blow-out impulse on the cathodes of the even tubes to force the cathode potential of any conducting tube of this group above its anode potential and thereby cause the previously conducting even tube to be extinguished.

Similarly the other blow-out tube 141 has its control grid coupled over the other diode of the tube 146 to the conductor 121 which couples the anodes of the even tubes together and has its anode coupled over a capacitor to the conductor 131 which couples the cathodes of the odd tubes together. Conduction beginning in any of the even tubes will cause blow-out tube 141 to cease conducting and send a positive blow-out impulse to the cathodes of the odd tubes to cause any previously conducting tube of the odd group to be extinguished.

It is to be noted that as in the case of the embodiment in Fig. 3, the anodes of the blow-out tubes 140 and 141 of Fig. 4 are supplied with +420 volt anode potential and strong positive blow-out impulses are obtained which will insure that a previously conducting tube of one group will be extinguished when a tube of the other group is fired.

An output tube 149 similar to those used with the circuits of Figs. 1 and 3 is provided to produce an output impulse each time the tube is fired. In this embodiment the output tube is connected to the ignitcr 1 of the 0 tube to receive a positive firing impulse therefrom each time the 0 tube is fired and becomes conducting.

A presetting means which includes a capacitor 151, similar to the capacitor 62 of Fig. 1, is provided to preset the counting ring by causing any desired tube to become conducting.

The operation of the counting circuit of Fig. 4 is substantially the same as the operation of the circuits of Figs. 1 and 3, negative input impulses causing the stepby-step firing of the tubes of the ring and the firing of a tube in one group of tubes of the ring causing an operation of the blow-out tube means to extinguish the previously conducting tube in the other group of tubes of the ring.

In all three embodiments of the invention, the blowout tubes, which are external to the tubes of the ring, enable strong blow-out impulses to be applied to the ring to insure that a previously conducting tube of the ring will be extinguished each time a new tube is fired and becomes conducting. The external blow-out tubes enable very reliable operation of the ring to be obtained.

While the forms of the invention shown and described herein are admirably adapted to fulfill the objects primarily stated, it is to be understood that it is not intended. to confine the invention to the embodiments disclosed. herein for it is susceptible of embodiment in various other forms.

What is claimed is:

1. In a device of the class described, the combination of a plurality of gaseous electron tubes, each tube having at least a pair of electrodes forming a main gap, an igniter cooperating with one of said main gap electrodes to form a starter gap, and a probe located in the ionizablemedium of the main gap and capable of exerting a control when conduction occurs in the main gap; a first main. gap electrode potential supply connected to the main gap electrodes of half the tubes and forming them into a first group; a second main gap electrode potential supply connected to the main gap electrode of the otherhalf of the tubes and forming them into a second group; means connecting the tubes for operation in a series, using tubes of the first and second groups alternately, the connection between adjacent tubes of the series ex-- tending from the probe electrode in a tube of one group- '10 to the ignitcr in the starter gap of the tube of the other group, and enabling conduction in the tube in which the probe is located to prepare the starter gap of the next tube of the series for firing in response to an input impulse; means to impress input impulses on said one of the main gap electrodes in each of the tubes in both groups; a blow-out tube having a pair of main electrodes and means for controlling conduction therebetween; an operating potential supply circuit for said blow-out tube, including an impedance'for producing a potential change at one of said main electrodes of the blow-out tube whenever the conducting status of the blow-out tube changes; means connecting the control means of the blow-out tube to one of the main gap electrodes of each of the tubes of the first group of tubes to change the conducting status of the blow-out tube each time one of the tubes of the group is fired; means connecting said one of the main electrodes of the blow-out tube to the other of the main gap electrodes of each of the tubes of the second group of tubes to enable the potential change at said one main electrode of the blow-out tube to produce a strong potential surge in the potential supply of the second group of tubes to extinguish any previously-conducting tube therein; a second blow-out tube having a pair of main electrodes and means for controlling conduction therebetween; an operating potential supply' circuit for said second blow-out tube, including an impedance for producing a potential change at one of said main electrodes of the second blow-out tube whenever the conducting status of the second blow-out tube changes; means connecting the control means of the second blow-out tube to those main gap electrodes of the tubes of the second group of tubes to which the blowout impulse was not applied, to change the conducting condition of the second blow-out tube each time one of the tubes of the second group is fired; and means connecting said one of the main electrodes of the second blow-out tube to the main gap electrode of each of the tubes of the first group which was not used to control the first blow-out tube, to enable the potential change of said one main electrodeof the second blow-out tube to produce a strong potential surge in the potential supply of the first group to extinguish any previously-conducting tube therein.

2. A device as claimed in claim 1 in which the electrodes forming the main gaps in the gaseous electron tubes of the groups are anodes and cathodes; in which the connections from the groups of tubes to the control means of the blow-out tubes extend from the cathodes of the tubes of the-groups; and in which the connections from the said one main electrodes of the blow-out tubes extend to the anodes of the tubes of the groups.

3. A device as claimed in claim 1 in which the electrodes forming the main gaps in the gaseous electron tubes of the groups are anodes and cathodes; in which the connections from the control means of the blow-out tubes extend to the anodes of the tubes of the groups; and in which the connections from the said one main electrodes of the blow-out tubes extend to the cathodes of the tubes of the groups.

4. In a device of the class described, the combination of a first plurality of gaseous electron discharge tubes; a second plurality of gaseous electron discharge tubes; each tube of the first and second pluralities of tubes having at least an anode and a cathode forming a main gap, an igniter cooperating with the cathode to form a starter gap, anda probe located in the ionizable medium of the main gap and capable of exerting a control when conduction occurs in the main gap; an anode-cathode potential supply circuit common to the tubes of the first plurality of tubes and connecting them into a first group; an anode-cathode potential supply circuit common to the tubes of the second plurality of tubes and connecting them into-a second group; said anode-cathode potential supply circuits including impedances whichcause the potentials of the anodes and cathodes of a group to change whenever a tube in the group conducts; means connecting the tubes for operation in a series, using tubes'of the first and second groups alternately, the connection between adjacent tubes of the series extending from the probe electrode in a tube of one group to the igniter in the starter gap of a tube of the other group, and enabling conduction in the tube in which the probe is located to prepare the starter gap of the next tube of the series for firing in response to an input impulse; means to impress negative potential input impulses on the cathodes of both groups of tubes to cause the firing of the prepared tube; a pair of normally non-conducting blow-out tubes, one for each of said groups of gaseous electron tubes, each blow-out tube having at least an anode, a cathode, and means to control conduction therebetween; a circuit connecting the anode of each blowout tube to the anodes of the tubes of its related group; and a circuit connecting the control means of each blowout tube to the cathodes of the other group of tubes and enabling the firing of a tube in one group to cause conduction in the blow-out tube of the other group, which conduction in a blow-out tube causes the potential of the anodes of its related group to drop and extinguish any conducting tube in its related group.

5. In a device of the class described, the combination of a first plurality of gaseous electron discharge tubes; a second plurality of electron discharge tubes; each tube of the first and second pluralities of tubes having at least an anode and a cathode forming a main gap, an igniter cooperating with the cathode to form a starter gap, and a probe located in the ionizable medium of the main gap and capable of exerting a control when conduction occurs in the main gap; an anodecathode potential supply circuit common to the tubes of the first plurality of tubes and connecting them into a first group; an anode-cathode potential supply circuit common to the tubes of the second plurality of tubes and connecting them into a second group; said anode-cathode potential supply circuits including impedances which cause the potentials of the anodes and cathodes of a group to change whenever a tube in the group conducts; means connecting the tubes for operation in a series, using tubes of the first and second groups alternately, the connection between adjacent tubes of the series extending from the probe electrode in a tube of one group to the igniter in the starter gap of a tube of the other group, and enabling conduction in the tube in which the probe is located to prepare the starter gap of the next tube of the series for firing in response to an input impulse; means to impress negative potential input impulses on the cathodes of both groups of tubes to cause the firing of the prepared tube; a pair of normally non-conducting blow-out impulse-generating tubes, one for each of said groups of gaseous electron tubes, each blow-out impulsegenerating tube having at least an anode, a cathode, and means to control conduction therebetween; an operating potential supply for each of the blow-out impulse-generating tubes, each supply providing a higher anode potential than that applied to the groups of tubes to enable a strong negative impulse to be generated when the impulse-generating tube conducts; circuits coupling the anode of each blow-out impulse-generating tube to the anodes ot the related group of tubes toimpress the ne ative impulses thereon to extinguish any conducting tube of the group; and connections between the control means of each impulse-generating tube and the cathodes of the tubes of the other group of tubes and enabling the firing of a tube in one group to cause conduction in the impulse-generating tube related to the other group, whereby the firing of a tube in one group will cause a negative impulse to be impressed on the anodes of the tubes of the other group to cause any conducting tube of the other group to be extinguished.

6. In a device of the class described, the combination of a first plurality of gaseous electron discharge tubes; a second plurality of electron discharge tubes; each tube of the first and second pluralities of tubes having at least an anode and a cathode forming a main gap, an igniter cooperating with the cathode to form a starter gap, and a probe located in the ionizable medium of the main gap andcapable of exerting a control When conduction occurs in the main gap; an anode-cathode potential supply circuit common to the tubes of the first plurality of tubes and connecting them into a first group; an anode-cathode potential supply circuit common to the tubes of the second plurality of tubes and connecting them into a second group; said anode-cathode potential supply circuits including impedances which cause the potentials of the anodes and cathodes of a group to change whenever a tube in the group conducts; means connecting the tubes for operation in a series, using tubes of the first and second groups alternately, the connection between adjacent tubes of the series extending from the probe electrode in a tube of one group to the igniter in the starter gap of a tube of the other group, and enabling conduction in the tube in which the probe is located to prepare the starter gap of the next tube of the series for firing in response to an input impulse; means to impress negative potential input impulses on the cathodes of both groups of tubes to cause the firing of the prepared tube; a pair of normally conducting blow-out impulse-generating tubes, one for each of said groups of gaseous electron tubes, each blow-out impulSe generating tube having at least an anode, a cathode, and means to control conduction therebetween; an operating potential supply for each of the blow-out impulse-generating tubes, each supply providing a higher anode potential than that supplied to the groups of tubes to enable a strong positive impulse to be generated when the impulse-generating tube ceases conducting; circuits coupling the anode of each blow-out impulse-generating tube to the cathodes of the related group of tubes to impress the positive impulses thereon toextinguish any conducting tube of the group; and connec tions between the control means of each impulse-generat ing tube and the anodes of the tubes of the other group of tubes and enabling the firing of a tube in one group to cause conduction to cease in the impulse-generating tube related to the other group whereby the firing of a tube 'in onetgroup will cause a positive impulse to be impressed on" the cathodes of the tubes of the other group to cause any conducting tube of the other group to be extinguished? 7. In a device of the class described, the combination of a first plurality of electron-discharge devices; a second plurality of electron-discharge devices, each of said de-' vices of said first and second plurality including at least two main electrodes and control means for controlling conduction therebetween; a first operating potential supply connected across said main electrodes of each of said dis charge devices of said first plurality and forming them into a first group; a second operating potential supply connected across said main electrodes of each of said discharge devices of said second plurality and forming them into a second group; means connecting said discharge devices together for selective-operation in a step-by-step sequence, using discharge devices of said first and second groups alternately, each connection between adjacent discharge devices in the sequence extending from-a discharge device in one group to a discharge device in the other group and enabling the discharge in the device in one group to prepare the next device in the sequence, which is in the other group, for discharge therein; means for supplying input pulses to the devices of both groups to cause any prepared discharge device to be rendered conductive; a blow-out impulse-generating device having at least a pair of electrodes and control means for controlling conduction therebetween, said control means of said blowout device coupled to one of said main electrodes of each of said discharge devices of said first group and one of said electrodes at said blow-out device coupled to the op erating potential supply of said second group of discharge devices to apply an extinguishing potential surge thereto each time a discharge commences in a discharge device of saidfirst group, whereby any conducting device of said second group is extinguished upon initial conduction in a device of said first group; and a second blow-out impulse-generating device having at least a pair of electrodes and control means for controlling conduction therebetween, said control means of said second blow-out device action in the respective groups, insuring that the discharge n in any conducting device is properly extinguished when a discharge commences in a succeeding device and that conduction takes place in only one device at a time.

8. In a device of the class described, the combination of a first plurality of gaseous electron-discharge devices; a second plurality of gaseous electron-discharge devices, each of' said devices of said first and second plurality including at least two main electrodes and control means for controlling conduction therebetween; a first operating potential supply connected across said main electrodes of each of said discharge devices of said first plurality, said potential supply connecting said devices of said first plurality in parallel with respect to one another and forming them into a first group; a second operating potential supply connected across said main electrodes of each of said discharge devices of said second plurality, said second potential supply connecting said devices of said second plurality in parallel with respect-to one another and forming them into a second group; means interconnecting said discharge devices of said two groups alternately into an operational series in which the conducting condition of said devices is advanced step by step, each series connection extending from a discharge device in one group to a discharge device in the other group and enabling the conduction in a discharge device in one group to prepare a discharge device in the other group for firing in response to an input impulse; means to supply input impulses to the discharge devices of both groups to cause any prepared discharge device to be fired and rendered conductive; a blow-out impulse-generating device having at least a pair of electrodes and control means for controlling conduction therebetween, said control means of said blow-out device coupled to one of said main electrodes of each of said electron-discharge devices of said first plurality to be controlled thereby, to change its conducting status each time one of said discharge devices of said first plurality is fired, and one of said electrodes of said blow-out device connected to the operating potential supply of said discharge devices of said second plurality to produce a strong potential surge therein to cause any conducting discharge device of said second plurality to be immediately extinguished; and a second blow-out impulse-generating device having at least a pan of electrodes and control means for controlling conduction therebetween, said control means of said second blow-out device connected to one of said main electrodes of each of said electron-discharge devices of said second plurality to be controlled thereby to change its conducting status each time one of said electron-discharge devices of said second plurality is fired, and one of said main electrodes of said second blow-out device connected to the operating potential supply for said discharge devices of said first plurality to produce a strong potential surge therein to cause any conducting discharge device of said first plurality of discharge devices to be immediately extinguished, whereby the firing of a discharge device in either group causes the operation of its related blow-out device to extinguish the conducting discharge device of the other group. I

9. In a device of the class described, the combination of a first plurality of gaseous electron-discharge devices; a second plurality of gaseous electron-discharge devices, each of said devices of said first and second plurality including at least two main electrodes and control means for controlling conduction therebetween; a first operating potential supply connected across said main electrodes of each of said discharge devices of said first plur ality and forming them into a first group; a second operating potential supply connected across said main electrodes of each of said discharge devices of said second plurality and forming them into a second group; means connecting the discharge devices into an operational series in which the conducting condition of the devices is advanced step by step, using discharge devices of the two groups alternately, each series connection extending from a discharge device in one group to a discharge device'in the other group and enabling the conduction in a device in one group to prepare the device in the other group for firing in response to an input impulse; means to supply input impulses to the devices of both groups to cause any prepared discharge device to be fired and rendered conductive; a blow-out tube'having at least a pair of electrodes and control means for controlling conduction therebetween,

said control means of said blow-out tube connected to one of said main electrodes of each of said electron-discharge devices of said first plurality to be controlled thereby, to change its conducting status to produce a strong blow-out impulse each time one of said discharge devices of said first plurality is fired, and one of said main electrodes of said blow-out tube connected to one of said main electrodes of each of said discharge devices of said second plurality to apply the blow-out impulse thereto to cause any conducting discharge device of said second plurality to be extinguished; and a second blow-out tube having at least a pair of electrodes and control means for controlling conduction therebetween, said control means of said second blow-out tube connected to the other of said main electrodes of each of said electron discharge devices of said second plurality to be controlled thereby to change its conducting status and produce a strong blow-out impulse each time one of said electron-discharge devices of said second plurality is fired, and one of said electrodes of said second blow-out tube connected to the other main electrode of each of said discharge devices of said first plurality to apply the blow-out impulse thereto to cause any conducting discharge device of said first plurality to be extinguished; the blow-out tubes operating alternately as the discharge devices of the series are fired in response to input impulses and insuring that a previously conducting device of the series is extinguished each time another device in the series is fired.

10. In a device of the class described, the combination of a first plurality of gaseous electron-discharge devices; a second plurality of gaseous electron-discharge devices, each of said devices of said first and second plurality including at least two main electrodes and control means for controlling conduction therebetween; a first operating potential supply connected across said main electrodes of each of said discharge devices of said first plurality and forming them into a first group; a second operating potential supply connected across said main electrodes of each of said discharge devices of said second plurality and forming them into a second group; means connecting the discharge devices into an operational series in which the conducting condition of the devices is advanced step 15 by step, each series connection extending from a discharge device in one group to a discharge device in the other group and enabling the conduction in a device in one group to prepare a device in the other group for firing in response to an input impulse; means to supply input impulses to the devices of both groups to cause any prepared device to be fired and rendered conductive; a blow-out impulse amplifier tube for each of said plurality of gaseous discharge devices, each having at least a pair'of electrodes and control means for controlling conduction therebetween; an operating potential supply connected across said electrodes of said blow-out tubes for providing said tubes With a higher potential than that supplied to the'plurality of discharge devices to enable relatively large amplitude blow-out impulses to be produced upon a change in the conducting status of each of said blow-out tubes; means connecting said. control means of one of said blow-out tubes to one of said main electrodes of said electron-discharge devices of said first plurality to be controlled thereby, to change its conducting status and produce a strong blow-out impulse each time one of said discharge devices of said first plurality is fired; means connecting one of said electrodes of said blow-out tube to one of said main electrodes of each of said discharge devices of said second plurality to apply the blow-out impulse thereto to cause any conducting discharge device of said second plurality to be extinguished;

16 means connecting said control means of the other of said blow-out tubes to the other of said main electrodes of each of said electron-discharge devices of said second plurality to be controlled thereby to change its conducting status and' produce a strong blow-out impulse each time one of said electron-discharge devices of said second plurality is fired; and means connectingone of said electrodes of the otherof said blow-out tubes .to the other main electrode of each of said discharge devices of said first plurality to apply the blow-out impulse thereto to cause any conducting discharge device of said first plurality to be extinguished, the blow-out tubes operating alternately as the discharge devices of the equence are fired in response to input impulses and producing large-amplitude blow-out impulses to insure that a previously conducting device of the series is extinguishedeach time another de vice in the series is fired.

References Cited in the file of this patent UNITED STATES PATENTS 2,303,016 Blount Nov. 24, 1942 2,404,739 Mumma July 23, 1946 2,447,134 Nims Aug. 17, 1948 2,503,127 Mumrna Apr. 4, 1950 2,549,769 Bray Apr. 24, 1951 2,644,112 Desch June 30, 1953

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