US2478902A - Electric system, including a vaporelectric discharge device - Google Patents

Description

- 1949- H. E. EDGERTON 2,478,902

- ELECTRIC SYSTEM, INCLUDING A VAPOR ELECTRIC DISCHARGE DEVICE Original Filed Aug. 16 1933 OSCILLATOR INVENTOR. HAROLD E. EDGERTON BY A I ATTORNEY Patented Aug. 16, 1949 ELECTRIC SYSTEM, INCLUDING A VAPOR- ELECTRIC DISCHARGE DEVICE Harold E. EdgertomBclmont, Mass. Originalapplicatiori August 16, 1933, Serial No.

Divided and this application August 5, 1946, Serial No. 688,406

9 Claims. (01. 315-261) The present invention, though having fields of more general usefulness in electric systems, is particularly related to systems in which the discharge of a flash condenser is employed for such purposes as to produce a single flash or a repetition of flashes in flash-photography and stroboscopic work. The present application is a division of application Serial No. 685,501, filed August 16, 1933.

An object of the present invention is to provide a new and improved electric system of the abovedescribed character.

Another object is to provide a new and improved condenser-charging system.

A further object is to improve the efiiciency of condenser-charging systems.

Other and further objects will be explained hereinafter and will be particularly pointed out in the appended claims.

With the above ends in view, a feature of the invention resides in charging the condenser from a source of direct current through a series-connected reactor.

The invention will now be more fully explained a in connection with the accompanying drawing, the single figure of which is a diagrammatic view of circuits and apparatus arranged and constructed according to one embodiment of the invention, illustrating a stroboscopic light source. A flash condenser or capacitor 26, charged from a direct-current battery I02, is shown series-connected by wire conductors 8 and I0 in a discharge circuit to the anode 6 and the cathode 4 of a normally non-conducting gaseous-discharge or vapor-electric discharge device, such as a flashlamp 2. The flashes are produced by discharging the condenser 26, after it has become charged, through the discharge circuit and through the gaseous medium of the lamp 2, between the anode B and the cathode 4. The condenser 26 may be charged to a voltage of from 200 to 2000 volts.

The lamp 2 is illustrated as of the mercury-arc type, the cathode 4 being in the form of a liquid pool of mercury. The lamp is shown as provided not only with the cathode 4 and the anode 6, between which the flash-producing current is sent through the mercury vapor of the lamp, but also with a starting control-grid electrode I00, situated around the glass, outside of the mercury Pool.

conductor I0 or, as illustrated, in the wire conductor 8. The impedance 35 should be designed sufficiently large so that, after the discharge of the condenser 26 between the cathode 4 and the anode 6, further current flow between them will be prevented until after the space in the lamp 2 between the electrodes 4 and 6 shall have again become deionized. The impedance 35 should, however, be small enough to allow the condenser- 26 to become recharged with energy from the battery I02 in time for the next flash. These ends may be attained by connecting a suitably reactive impedance 35 in series with the condenser 26 and the battery I02. The reactor 35 thus constitutes part of the means for charging the capacitor 26..

The impedance 35 thus inserted between the condenser 26 and its charging source I02 provides also for a proper charging rate of the condenser- 26, Its size and characteristics should be determined by the characteristics of the flash lamp 2 or other apparatus and the desired time interval between the condenser discharges.

Because of the dielectric properties of the nor-- mally deionized mercury vapor in the space between the cathode 4 and the anode 6, if the mercury-arc tube 2 has been exhausted adequately, the battery I 02 will charge the condenser 26 through the impedance 35 without any of its energy traversing that space. A difference of potential will therefore be established between the cathode 4 and the anode 6 during the charge of the condenser 2Iibefore each flash.

A trip circuit is shown comprising a high-ratio step-up triggering flash transformer 30, a normally non-conducting mercury-vapor 'thyratron trigger tube I40, two impedances 3| and 33,'shown as resistors, and a small trip condenser 28. The secondary winding 29 of the transformer is connected between the starting electrode I00 and. the cathode 4. The trip condenser 28 is shown charged from a second battery IOI, through the impedance 3|, which may perform a function similar to that of the impedance 35-. The thyra-- tron I40 and the primary winding 36 of the transformer 30 are connected in the discharge-circuitof the trip condenser 28. The resistor 33, shown shunted across the trip condenser 28, allows a small current to flow, in order to maintain upon the control grid 50 of the thyratron l40 a voltage bias suitably negative with respect to the thyratron cathode 48. The anode of the thyratron I40 is shown at 52.

The trip circuit functions to discharge the trip condenser 28 through the mercury of the thyratron I40 and the primary winding 36 of the flash transformer 30. The direct-current energy of the second battery NH becomes thus eonver ted ir -to sudden-pi ilse's the primary winding 36. discharge of the trip condenser 28 is effected at selected intervals, whenever it is desired to produce the flash, under the control of the thyratron grid 50. The potential on the grid; 50-in"tul n;is"' shown controlled, for stroboscopic purposes; by

an oscillator 62, through a transformer 64;. The oscillator 62 supplies positive charges intermittently to render the lamp 2 conducting;- Other methods of controlling the grid 50 are disclosed in the said application.

The vantage ulses prod'uced in the primar winding ifi in res onse to the discharge Of the trip condenser 28 are conveyed, th'rciugh the'sondary Winding 29 of the transformer 3U',Jt0 the starting electrode Hm toim res a hign- 'otent'ia1 stimulus of charge thereon. The mei-tur vapor in the'lainp' between the cathode 4 a11'dthe andd '6 becoming-thereby ionized; the flash con-- dllsl 23 discharges slllidenly thldligh'its TITS charge circuit. As the condenser 26 is' conneeted betWh"the C2ItY10de"4 alid 'the allddh, ayef'jllarge current, over one thousand ampereathere; upbfl"surges through the lamp Z b'twe e rithe Cathode 4 and the anode 6, producing a very bii-l l'iant intense quick fiasii'oi'light. The operation of the'lamp [from the discharged the capacitdr ZG'YS thus iii'lti'aite'dby'th C'OntlOl fibtddn the thyratron grid "50", energizing the starting electrode NW; The duration of the fiashis ofth orderof microseconds, as determined by the size Ofth'ecapacity' 2c, the voltage to which it is charged, theTdil'l'i'nls'iofis of the 1ati1p'2; tl'idli'i peda'nb'eof the leads Band Ill cbIihCtihgTthe'Cbndehser26,'and other factors. Under sonie conditib'n's; the duration Of the 'flaSh iS less than ofi microsecond;

The instantwhen the hash occurs is thus' accurate'lytimedwithout the aid of any siiriths in the high-voltage circuit, merely by having. the oscillator, 62 supply positive charges interim tentlyt'o" the thyra't'ron grid 50'. This resultsin intermittently energizing the primary winding 36" to cause the starting electrode IMF to enable the condenser 26 to discharge intermittently hetween the" cathode [and the a'iiode 6, thereby practicing intermittent "flashes of light. Other methods of co'ntrollingithe grid 50" are described in the said. application.

The suddenly-applied relatively highvolta'ges intermittently. produced by the trip-potential surges on the grid'SD across-the terminals of the secondary winding 29 will cause abright cathodespot to formintermittentlyon the surface of the mercury cathode 4' and' at the junction between the mercury. and the inner wall or the-glasstube. The-gas in the-tube becomes thus ionized, The bright spot constitutes a---source; oi electrons in the vicinity of the' cath'ode 4 that :supplies elec; trons for the :dischargeot the condenser 26- ties orseidiaritp' t r through the tube 2 between the anode 6 and the cathode 4.

Modifications will occur to persons skilled in the art, and all such are considered to fall within the spirit and scope of the invention, as defined in the appended claims.

What is claimed is:

A stroboscope comprising a source of supply of direct current, a reactor and a capacitor arranged in series and connected with said source, a vapor electric discharge device connected to be energized from said capacitorandprovided with acontrohgrijd and means for controlling the charge on said grid.

I 2. A stroboscope comprising a source of supply of direct current, a reactor and a capacitor arranged inseries and connected with said source, a vapor-el e'ctric discharge lamp connected to be operated by the discharge from said capacitor, arid grid control means for initiating the opera- 3i; A%*stroboscope*comprising a source of supply of direct "current; a reactor, a capacitor connected to be *charged through said reactor from said source, a grid controlled vapor electric discharge device arranged to be energized bythe discharge from saidcapacit'orafid means for intermittently supplyin'g a positive charge to said grid. 0 A I 4. V A stroboscope having, in icornbinatioma tube having an anode, a mercury-pool cathode, and a starting electrode, a condenser connected between the anode and the cathode, means comprising a reactor for charging'the; condenser, atransformerhaving a primary winding and a secondary wind ing means connecting the secondary Winding between the cathode and the starting electrode; and means for intermittently energizing the primary winding to causethe secondary winding to energize the starting electrode intermittently andthereby to produce intermittently a source of electrons on the mercury-pool cathode; whereby the condenser T will become enabled to discharge intermittentlybetweenthe cathode and the anode to produce intermittently fiashesof light.

5. A light fiash producerhaving} in combination', a 'normally' non-conducting gasous dis charge: lamp having an anode, a'-- cathode" and astarting electrode and through which} Whenth lamp'is conducting-a discharge may past'tetwee the cath'ode and-the anode, a condene'r' connected between the cathode" and the anode, meanscom-'* pt I ing a-freactor for charging the'condense'riand means for energizing the startingelectrode to rendrthe lamp conducting, whereby the con: d nser-win-become nabled to;discharge-betwee tca'thode" andthe anode to produce flash of Ig c Y c; vA stroldoscope'having, 'iri coifibiii'atioii, Ia maiiy n'o'ri co ndiictifig g d ehargei enip havingananod'e, a 'csthotiejand a-- startiiig elec'k troliearid through which, ilvh'eh'th lamp is @0115 ducting, a' dischargemay pass between-the e ch ode and the anode',,'a condenser connected be tween the cathode and thetanodei means comprisinga reactorfor charging the condenser, a transformer having. at primary winding and a seebtidary wmdmg;me ns connecting; the;secondary'winding between the cathode and thestarting electrode, an'd'means for intermittently energiz tween the cathode and the anode to produce intermittently flashes of light.

7. In combination, a source of supply of direct current, a reactor and a capacitor arranged in series and connected with said source, a vaporelectric-discharge device connected to be energized from said capacitor and provided with a control grid and means for controlling the charge onsaid grid.

8. In combination, a source of supply direct current, a reactor and a capacitor arranged in series and connected with said source, a vaporele'ctric-discharge lamp connected to be operated 10 plying a positive charge to said grid.

HAROLD E. EDGERTON.

No references cited.

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