US2473832A - Electrical system - Google Patents

Description

Jupe 21, i949." P, w. sTUTsMAN l ELECTRICAL SYSTEM 2 shets-sheet 1 Filed April 14, 1944 P. w. lsTUTsMAN ELECTRICAL SYS TEM June 21, 1949.

Filed April 141944 2 Sheets-Sheet 2 VVVVVVVV Patented June 2.1, 1949 ELECTRICAL SYSTEM Paul W. Stutsman, Needham, Mass., assignor, by

mesne assignments, to Raytheon Manufacturing Company, Newton, Mass., a corporation of Delaware Application Apri1 14, 1944, serial No. 531,067

7 Claims.

This invention relates to electrical systems and more particularly to electrical signal systems for visible signalling.

Electrical signalling systems are known in which a relay and signal lamp are used to produce a visible signal. These systems, however, are objectionable, particularly in portable systems, on account of the weight of the relays.

One of the objects of the present invention is to provide an electrical signalling system in which this difficulty is overcome by substituting a novel tube that makes it possible to do away with the relay.

Electrical signalling systems heretofore used are also open to the objection, when it is desired to use a very small signal voltage, that they require the application of a relatively higher voltage in order to lire the tube. The present invention overcomes this objection by providing two auxiliary electrodes in addition to the anode and cathode, and so arranged that when a signal in put voltage is applied between said two auxiliary electrodes and the anode and cathode respectively, the signal input voltage will be added to the cathode-anode voltage to raise the voltage across a gap within the tube to the breakdown point, the magnitude of the signal input voltage required to be added being relatively small, so that tubes embodying the present invention may be made to re on a very low signal input voltage.

In such electrical signalling systems, transient voltage differences may occur between different circuits which may not only be disturbing but may even re the tube.

Another object of the present invention, therefore, is to eliminate the effect of such transient voltage differences.

When devices of the above type are used in telephone systems comprising a plurality of signal circuits, there is a tendency to produce what is known as crosstalk, that is to say, conversation upon one line reproduced upon another. A further obj ect of the present invention is to eliminate such crosstalk or to attenuate it sufficiently to render it unobjectionable.

A further object of the present invention is to provide an improved gaseous conduction tube.

These and such other aims and objects of the present invention as may hereinafter appear will be readily understood from the following description, taken in connection with the accompanying drawing, of embodiments of the invention herein presented for illustrative purposes.

In the drawing: Fig. 1 is a vertical cross-section on line I-I of Fig. 2 of a tube embodying one illustrative embodiment of certain features of the invention;

Fig. 2 is a horizontal cross-section on line 2-2 of Fig. 1 but showing the tube elements inplan;

Fig. 3 shows an electrical signalling system embodying one illustrative embodiment of the invention;

Fig. 4 shows an electrical signalling system embodying another illustrative embodiment of the invention; and

Fig. 5 illustrates an electrical signalling system embodying a further illustrative embodiment of the invention.

Referring to Figs. 1 and 2, in the illustrative embodiment of the invention therein shown, the signal lamp comprises a glass envelope 2 containing a suitable ionizable gaseous medium and an electrode assembly comprising a cathode 4, an anode E, and two grids or auxiliary electrodes 8 and lo. Said cathode may be relatively large and in this illustrative embodiment of the invention is shaped like an inverted bowl provided with a relatively large, central circular aperture I2 through which said anode 6 and the two auxiliary electrodes 8 and I0 extend upwardly. The lower ends of said anode and said two auxiliary electrodes are sealed in a press I4 formed upon the upper edge of the reentrant stem I6 of said envelope, the lower edge of said envelope 2 being hermetically sealed'to the flare I8 of said stem IVE. Above said cathode, said auxiliary electrode 8 is shown as bent horizontally away from the anode, then downwardly, and then circularly in a plane substantially parallel and in proximity to the upper surface of said cathode, this portion of said auxiliary electrode thus forming almost a. complete circle and presenting an extended active area to the upper electron-emissive surface of said cathode. The auxiliary electrode Ill extends substantially parallel to the anode 6, its upper end being bent at right angles across the latters upper end. Means may be provided to prevent premature ignition, such as a shield 20 surrounding the anode 6, and herein conveniently consisting of a glass cylinder integral with said stem I6. The cathode is supported by a post 22, the lower end of which is sealed in said press I4. A conductor 26 connects the cathode with a lead-in conductor 28, and the lower ends of said anode and of said two auxiliary electrodes 8 and lil are joined to lead-in conductors 30, 32 and 34, respectively.

The signal lamp as above described, including the electrode assembly and other parts therein contained, may and preferably will be the same 3 for all embodiments of the present invention herein disclosed. In the description of Figs. 3, 4 and 5 therefore, such parts of the tube as may be referred to will be designated by the same reference numerals as in Figs. 1 and 2.

Referring to Fig. 3, auxiliary electrode 8 is connected bya conductor 32 to one terminal 36 of the signal input circuit, and auxiliary electrode I is connected to the other terminal 38 of said signal input circuit by conductor 34 through a resistance 56. It may be advantageous to use a. voltage storage device, such as condenser 44, in this circuit as will be hereinafter more fully explained. The conductor 26, joined tothe cathode 4, is connected by conductor 2B to one pole 48 of a battery or other suitable source 50 of D. C. voltage which may be adjustable 'and anode 6 lisvcon-v nected to the other pole 52 of said source by conductor 30. will preferably, be included in said anode-cathode circuit.

In this embodiment of the invention when volt'- ages of from 135 to.:180 -volts are available; neon gas may be used at'a pressure of 40 mm. of mercury.

The-signal discharge'may'be initiated in either one of two ways or both. It may be initiated directly between the twoiauxiliary electrodes and IllJ to produce sufcient'ionization for the discharge to start betweenthe cathode 4 and the anode 6. It isconceivable', however, that for some reasonthe initiationof the discharge might not take place between said two auxiliary electrodes. Such a condition might 'existif the spacing of said two auxiliary electrodes were too great for theavailablesignal voltage alone to break down, or the signal voltage .might be too low to effect abreakdown evenif the spacing of said two auxiliary electrodes were at the minimum breakdown distance. Insuch case it` has been found that the'discharge may be initiated between the auxiliary electrode 8 and kthe cathode 4, and between the auxiliary electrode I0 and the anode 6. It is believed that this may be due to the fact that the signalvoltage may build up a potential on saidiauxiliary electrode.` 8, which is lpositive with respect to said'auxiliary electrode I8, and the anode-cathode voltage makes the anode 6 positive with respect tothe cathode4 4. Under these conditions, the signalivoltage willadd to the anode-cathode voltage and. thus the total voltage impressed across: the gaps between `the auxiliary electrode 8 andthecathode 4'and between the auxiliary electrode I Uand'theanode B will be thesumpf said signal and anode-cathode voltages. The'voltages across these gaps may thus be raised to the breakdown point. If .this theory is correct the magnitude of the signal input'voltage required` to produce breakdown becomes a function of the `anode-cathode voltage, increasing and decreasingginversely to the increase or decrease of the anode-cathode voltage.

To illustrate, let us consider Fig. 3. As pointed out above, when the auxiliary electrode 8 is positive with respect to the auxiliary'electrode I0, then voltage from the signal voltage will be added to the anode-cathodevoltage 50, across the gaps 4 8 and `I 8 6.

Let us suppose that the anode-cathode circuit voltage Ea is 180 volts D.,C., that the voltage required for breakdown between cathodev 4 and the auxiliaryelectrode `8.is 110 volts, and that the samevoltage will be` required. for breakdown be- A current-limiting resistance 58 tween anode y6 and.'auxiliary electrode |0, The

necessary starting potential to break down both 4 gaps 4--8 and I-- would therefore be 220 volts, which is made up of D. C. voltage, supplied by the anode-cathode circuit 50, and A. C. voltage supplied by the signal input circuit 5I. If we designate by Es the R. M. S. A. C. voltage of the signal input circuit 5 l, then ES=EO Sin wt where E0 designates the peak signal input circuit voltage. The tube will therefore fire when (l) Ea-i-Eo sin wt=220 volts Thus i (2) 220 volts-Ea=Eo sin wt But we know that (3) Ea=180 volts therefore from (2) (4) 220 volts-180 volts=40 volts and (5) Eo=40 volts when Sin wt=1 The signal input' circuitvoltagerequired to be added' to thel'peak'voltage of the anode-cathode circuit for starting the tube would be 40 volts peak, or; reduced to R. M. S. A. C., it would be equal to The signal input circuit voltagerequired .to start the tube is therefore a-functlon of the applied anode-cathode'circuit voltage. Once initiated between the cathode and auxiliary electrode 8, .the discharge will pass on through thezsignal input circuit to auxiliary/'electrode l0.and.from the latter to the anode. Thereupon thefdischarge is nally initiated between .said anode and cathode.

It has beenstated abovelth'at the use ofa condenser in thesignal input circuit might be advantageous. Ithasbeen found infact that under certain vconditionswthe Luse 'of Ta condenser, shown at44'in Fig. 3,' reduces thestarting voltage. Thus, with a condenser having a capacitance of .005 microfarad, theslgnal starting voltage-'Was' reducedfrom rrvoltsR. M. S. to50 volts'R. M. S. and the :peak from 91 vvoltsto 70 volts.

When a plurality of devices. as. illustrated in Fig. Bare utilized 1inV a; single telephone system where the voice signals also appeal-:across the lines 32fand 34, there will be substantially no tendency to produce-crosstalk'.A since there :is vsubstantially infinite impedance between thesignalinput circuit and the anode-cathodescircuit vwhen the tube is not conductingI as is theoase during the `period when speech is being=transm.itted,` and thus no crosstalkI caribe transmitted, Referring to.-Fig. 3 -it will beeseen that-as previouslystated, in .the illustrative embodiment f of. the invention therein shown,` the auxiliary. electrode 8 is directlyfconnected to one terminal y3irof-fthesignal input circuit byfconductor. 32 andthatauxiliary electrode l0 is directlyconnected to theother terminal `38 ofy said circuit bysconductor 34. The signal input circuit is therefore. disconnected externally from the anode-cathode circuit,so that as abovestated, when the tubeis-not conducting,- thereis -substantially inniteimpedance .between'the signal input circuit and the anode-cathodecircuit and crosstalk is excluded.

In the embodiment;v `of the :inventionillustrated in Fig. 3, the auxiliary electrodes 8 and l0 float ammessa This is duey at least in part to the favorable relative positions of said two auxiliary electrodes 8 and l to the other elements of the tube and the associated circuit. While the potential required for ignition has been reduced, premature ignition between the anode and the cathode, before a working voltage has been attained, is prevented by suitable means, such as a shield 20 (see Fig, l), that encloses the anode throughout that part where such premature ignition might occur. The signal input voltage may be made as low as may be desirable.

I Firing of the tube except when the desired and necessary signal input voltage is applied, and which was heretofore caused by transient disturbing voltage differences that may occur between circuits, has been eliminated and crosstalk in those systems wherein it is likely to occur has also been substantially eliminated or so attenuated that it is unobjectionable.

Systems embodying the present invention are also considerably lighter in weight where the lamps take the place of lamps and relays. Other advantages will suggest themselves to those skilled in the art.

I am aware that the present invention can be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present description to be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the aforesaid description to indicate the scope of the invention.

What is claimed is:

1. In an electrical system, a gaseous conduction tube comprising an hermetically sealed envelope containing an electrode assembly cornprising an electron-emissive cathode, an anode and two auxiliary electrodes; an anode-cathode circuit comprising said anode and said cathode; a signal input circuit comprising said two auxiliary electrodes; and means comprising a bypass condenser, connected between said two circuits, for by-passing transient voltage differences that might occur between said two circuits thereby preventing said transient voltage differences from ring the tube.

2. In an electrical system, a gaseous conduction tube comprising an hermetically sealed envelope containing an electrode assembly comprising an electron-emissive cathode, an anode and two auxiliary electrodes; an anode-cathode circuit comprising said anode and said cathode; a signal input circuit comprising said two auxiliary electrodes; resistance means connected between said two circuits; and condenser means shunted around said resistance means.

3. In an electrical signal system, a gaseous conduction tube comprising an hermetically sealed envelope containing an electrode assembly comprising a glow discharge cathode, an anode and two auxiliary electrodes; an anode-cathode circuit comprising said anode and said cathode; a signal input circuit comprising said two auxiliary electrodes; and means comprising a by-pass condenser, connected between said two circuits, for ley-passing transient voltage diierences that might occur between said two circuits thereby preventing said transient voltage diierences from firing the tube.

4. In an electrical signal system, a gaseous conduction tube comprising an hermetically sealed envelope containing an electrode assembly comprising a glow discharge cathode, an anode and rtwo auxiliary electrodes; ananode-cathode circuit comprising said anode and said cathode; a signal input circuit comprising said two auxiliary electrodes; resistance means connected between said two circuits; and condenser means shunted around said resistance means.

5. In an electrical signal system, a gaseous conduction tube comprising an hermetically sealed envelope containing an electrode assembly comprising a glow discharge cathode, an anode and two auxiliary electrodes; an anode-cathode circuit comprising said anode and said cathode; a signal input circuit containing said two auxiliary electrodes and current-limiting resistance means; and condenser means connected between said two circuits.

6. A glow discharge lamp comprising a sealed envelope containing a light-producing gas at substantial pressure, said envelope having an insulating stem through which a plurality of conducting leads are sealed, an insulating sleeve projecting into said envelope from said stem and surrounding one of said leads, said sleeve being open at its inner end to permit the inner end of the lead which it surrounds to act as an anode, a cup-shaped cathode supported by another of said leads, said cathode having its convex surface facing away from said stem and having a central opening through which said sleeve projects, an auxiliary ring-shaped electrode supported by another of said leads and lying closely adjacent the convex surface of said cathode, and a second auxiliary electrode connected to another of said leads and overlying the open inner end of said sleeve in close juxtaposition to the anode.

7. A glow discharge lamp comprising a sealed envelope containing a light-producing gas at substantial pressure, said envelope having an in'- sulating stem through which a plurality of conducting leads are sealed, an insulating sleeve projecting into said envelope from said stem and surrounding one of said leads, said sleeve being open at its inner end to permit the inner end of the lead which is surrounds to act as an anode, a cup-shaped cathode supported by another of said leads, said cathode having its convex surface facing away from said stem and having a central opening through which said sleeve projects, an auxiliary ring-shaped electrode lsupported by another of said leads and lying closely adjacent the convex surface of said cathode, a second auxiliary electrode connected to another of said leads and overlying the open inner end of said sleeve in close juxtaposition to the anode, and an opaque shield surrounding said envelope, said shield being provided with a window at one end whereby the light generated at the convex surface of said cathode may be observed through said window.

PAUL W. STUTSMAN.,

REFERENCES CITED The following references are of record in the rile of this patent:

UNITED STATES PATENTS Number Name Date 1,144,596 Hewitt June 29, 1915 1,506,468 White Aug. 26, 1924 1,550,877 Chaffee Aug. 25, 1925) 1,838,871 Schmierer Dec. 29, 1931 1,893,638 Schmierer Jan. 10, 1933 1,947,774 Heany Feb. 20, 1934 2,113,464 Hazeltine Apr. 5, 1938 "5 withrespect to the anodeandcathode. This has a tendency to renderthe tube somewhat unstable. To remedy this and to stabilize the tube it is preferableto provide stabilizing means, such as, for example, a grounded shieldfSD of metal or other suitable electrically conductive material. A(See Fig, 3.) If desired :said shield may completelyenclose the tube except at fthe top and bottomthereof so as to conne the light to what `isemitted through the top of said'shield. If desired the light from the tube may be further localized by insertionof a lens 93 in the top of the cylinder 90.

Ystabilizing circuit arrangements may also be .utilized such as shown inthe illustrative embodiment of Fig. 4. In this embodiment the auxiliary electrode 8 is connected by conductors 32 and 68 to one terminalv62 of the vsignal input cir- .cuit and the auxiliary electrode I is connected by conductors 34 and 64' to the other terminal 66 of said circuit, a current-limiting resistance 68 4being preferably inserted in said circuit. The anode 6 is connected to the'positive pole of a source of D. C. voltage, battery 80, for example, for the anode-cathode circuit byconductors 30 and 82 through a resistance 84 for limiting the anode- .cathode current to working value, and the cathode 14' is connected to the negative pole of said source of D. C. voltage by conductors 28, v28, 8l and 88. The auxiliary electrode 8 is also connected to the negative pole of said source of D, C. voltage 88 by conductors '32, 9|, 81 and 8B through a rela- 'tively high resistance 'I0 and a current-limiting vresistance 68, and the auxiliary electrode is also connected to ksaid negative pole of said source of D. C. voltage 88 by ' conductors 34, 92, 9|, 8'!

-and 88 through a relatively high resistance le.

I have discovered that by using a discriminatory impedance network connected between the anode-cathode circuit and the signal input circuit vand comprisingfor example, a by-pass condenser 1.2 shunted around said resistance 1B, and a sec- .ond by-pass condenser T6 shunted around said .resistance 14, the benetsof circuit stabilization .are secured without introducing diiiiculties, such as undesired firing and crosstalk.

I have found that the transient disturbances .which tend to produce undesired firing are of relatively high frequency asfcompared to those voice .frequencies which carry the intelligible portions of the voice signal and said Voice frequencies are relatively high as compared to the signal frequencies. Due to said frequency diierences, the impedance of the members 12, 'l0 and 16, 'M can be made sufficiently low, relative to the undesirable transient voltage diiferences that may exist be- .tween said anode-cathode circuit and said signal input circuit and which might otherwise fire the tube, to by-pass said transient voltage, and yet sufficiently high with respect to the signal frequencies so as to permit a suiiiciently high signal voltage to be built up across said impedance to fire the tube. By a suitable adjustment of said impedance, crosstalk due to intercircuit coupling,

vvented by said condensers ||2 and H4.

rata higher voltage such as 135 to 180 volts. ypointed out above where such a higher voltage Whenz an anode-cathode voltage from to 135 4volts isavailable, avgaseous medium composed of a mixture of neon and argon gases (about 34.4 mm. of neon to 0.6 mm. of argon) may be used in the embodiment of '.Fig. 4. If higher voltages were available and as airesult a neon-rilled tube were to be used in the arrangement of Fig. 4, a continuous small discharge may be present be tweenthe anode and auxiliary electrode I8 due 'to the vconnections afforded by the resistances l"Hl and 14. Should'ithis be objectionable the embodiment of the inventionillustrated either in Fig. `3 `or inlig. 5 is preferable.

In the illustrative embodiment of the invention shown'inzFig` 5, auxiliary electrode 8 is connected through a currentlimiting resistance |08 to terminal 96 of the signal'input circuit by conductors 32,102 and auxiliaryV electrode I0 is connected through a current-limiting resistance ||0 to terminal 98 of said circuitbyv conductors 34, |86. In

this'embodiment ofzthe invention condensers I2 andi I4, like condensers 'l2 and 76 of the-previlously described embodiment of the invention disclosed in Fig. 4, can be adjusted to provide an impedance that is sufficiently low, relative to the undesirable transient voltage diierences that may exist between the anode-cathode circuit and the signal input circuit and Which'might otherwise re the tube to by-,pass said transient voltage differences, and yet to provide a sulciently high impedance with respect to the signal voltages as .to insure'the building up ofy a voltage across said .impedance that will be suiciently high to nre the tube. However, resistances across the condensers ||4 and ||2 such as are present in Fig. 4 are omitted. By such judicious adjustment of said condensers ||2 and ||4 it is possible to cause extraneous transient voltages to be by-passed and .substantially eliminated, and crosstalk, due to intercircuit communication when the invention is used in a system where it tends to occur, to be so greatly attenuated thatit becomes unobjectionable. These by-pass condensers ||2 and ||4 are connected to the signal input circuit by t .conductors H6 and ||8, respectively. They are also connected to the anode-cathode circuit, being connected to the negative pole of a source of D. C. voltage, such as a battery |20 for example, by conductor |23, the cathode 4 being connected .to the. negative pole of said battery by conductors 26, 28 and |23. The positive pole of said battery is connected to the anode 6 by conductor |24 through a current-limiting resistance |26.

As stated above where the anode-cathode voltage exceeds volts, the above described embodiment is preferable to that disclosed in Fig.

--4, as the continuous small discharge between the anode and auxiliary electrode |0 that may be present in said embodiment of Fig. 4 is pre- The system disclosed in Fig. 5 is designed to operate As is used, the tube may contain neon gas at a pres- .sureof approximately 4 cm. mercury.

The invention has been described by Way of yillustration in its application to electrical signalling systems for visible signalling. It should be understood, however, that the invention is in nowise limited to such particular application, certain of its features being equally applicable to other electrical systems.

The present invention is a distinct advance in the art. It has materially lowered the potential from the signal .circuit required for ignition,

Certicate of Correction Patent No. 2,473,832. June 21, 1949.

PAUL W. STUTSMAN It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 8, line 44, claim 7, for the Words which is read 'which it;

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case 1n the Patent OIice.

Signed and sealed this 22nd day of November, A. D. 1949.

THOMAS F. MURPHY,

Assistant Uommz'asoner of Patents.

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