US3115594A

US3115594A - Voltage doubling supply circuit for triggering and flashing gaseous discharge lamp

Info

Publication number: US3115594A
Application number: US33993A
Authority: US
Inventors: Henry R Mallory
Original assignee: ACR Electronics Corp
Current assignee: NABDCO ACQUISTION CORP A CORP OF FL
Priority date: 1960-06-06
Filing date: 1960-06-06
Publication date: 1963-12-24
Anticipated expiration: 1980-12-24

Description

Dec. 24, 1963 H. R. MALLORY VOLTAGE DOUBLING SUPPLY CIRCUIT FOR TRIGGERING AND FLASHING GASEOUS DISCHARGE LAMP Filed June 6, 1960 INVENTOR. HENRY R. MALLORY ATTO RN EYS United States Patent VQLTAGE DUUBLHNG SUKPLY CHRCUIT FOR TRIGGERHNG AND FLAflHlNG GASEQUfl DISCHARGE LAMP Henry R. Mallory, Greenwich, Conn, assignor to ACR Electronics Corp, New York, N.Y., a corporation of New York Filed June 6, 19%, Ser. No. 33,993 Claims. (Cl. 315-219) This invention relates to flasher circuits for high intensity beacon equipment and the like and to a voltagedoubler circuit adapted for use with such equipment.

Flasher circuits are employed to repetitively flash high intensity flash tubes, so that the tubes may be used as warning or signalling beacons and the like. Equipment of this nature should be self-contained, compact and light in weight to enable it to be used under a wide variety of conditions. For example, signalling beacons are often provided on life rafts, or as separately floatable units, to enable the survivors of ship or airplane disasters to attract help. Additionally, equipments of this nature are used as airplane anti-collision warning devices and as warning beacons for road construction work and the like to warn motorists and pedestrians of possible danger.

The usual source of power for beacon equipment is a battery which is packaged with the flash tube and circuit for flashing the tube in a highly compact manner. Since the intensity of the light from the flash tube is proportional to the square of the voltage applied to the tube, the battery employed should provide the maximum possible terminal voltage. Unfortunately, in order to obtain a sufiiciently high battery terminal voltage to operate certain types of flash tubes with the required intensity, it would be necessary to employ batteries having a very large number of cells, which would, of course, increase the weight and the size of the battery, to thereby limit the portability and compactness of the beacon equipment. Furthermore, some types of high intensity flash tubes, such as the xenon type, for example, may require voltages on the order of 150 to 180 volts DC for eflicient, reliable operation. Although a very recently developed type of xenon tube will operate from a terminal voltage as low as 100 volts, it nevertheless is desirable to increase the voltage applied to the tube, to thereby increase the intensity of the light flashes.

Some of the known types of flasher circuits for such beacon equipment employ A.C. voltage-doubler circuits to provide sufliciently high voltages for the flash tubes of the equipment from batteries of acceptable size and weight. These flasher circuits operate by converting or chopping the DC. battery voltage to obtain an A.C.

- voltage which is applied to one of the conventional types of A.C. voltage-doubler circuits. The substantially doubled A.C. output voltage from the doubler circuit is then rectified to obtain a DC. voltage for application to the anode and cathode elements of the flash tube. While flasher circuits of this type provide an increased output voltage for the flash tube from batteries of acceptable size and weight, the flasher circuit itself is obviously complex, ineflicient and not readily adaptable for compact packaging, due to the necessity of utilizing equipment for performing the double conversion of DC. to A.C. and A.C. back to DC. Furthermore, the known types of flasher circuits for beacon equipment usually fail completely when the flash tube does not ionize, due to a reduced battery voltage after long periods of use. Although D.C. voltage-doubler circuits are known which do not require the double conversion of DC. to A.C. and A.C. back to D.C., they have not been employed in flasher circuits for beacon equipment and the like. Generally, the known types of DC. voltage-doubler circuits operate by alter- Patented Dec. 24, 1963 "ice nately, successively charging capacitors in parallel circuit with the DC. voltage source and then discharging them in series circuit with the DC. source, to thereby provide a DC. voltage at the output of the circuit which is substantially double the source voltage. To accomplish this, the known types of DC. voltage-doubler circuits utilize complex relays or vibrators having at least two-pole, double-throw contact arrangements, which, of course, would so add to the size, weight, cost and complexity of any beacon equipment in which the doubler circuit might be used, as to render such use of little or no value compared to the use of A.C. voltage-doubler circuits.

Accordingly, it is an object of this invention to provide a flasher circuit for high intensity flash tubes and the like, which circuit operates from batteries having terminal volages as low as volts.

It is a further object of this invention to provide a DC. voltage-doubler circuit which employs a simple, commercially available, single-pole, double-throw relay with simple rectifier means, to permit the construction of simple, compact, light-Weight beacon equipment and the like.

it is a still further object of this invention to provide a flasher circuit for high intensity flash tubes and the like, which circuit continues to operate even through the flash tube may fail to ionize due to a reduced battery voltage.

Briefly, the flasher circuit of the invention employs a 11C. voltage-doubler circuit having unidirectional conducting means, such as a rectifier or diode, for example, serially coupled with the input of the circuit across the output of the circuit, and means for alternately, successively coupling doubler capacitor means to shunt the rectifier and to shunt the serially coupled rectifier and input. When the input of the circuit is coupled to a source of direct voltage, such as a battery, for example, the doubler capacitor means is charged by the source through the rectifier and is then shunted across the rectifier in a direction to prevent discharge of the capacitor means through the rectifier, so that the capacitor means is serially coupled in a voltage aiding direction with the source of direct voltage across the output of the circuit, to thereby substantially double the voltage from the source appearing across the output. When one side of the doubler capacitor means is coupled to the side of the rectifier adjacent the output, the switching operation may be performed by a simple, commercially available, single-pole, doublethrow relay by coupling the pole contact of the relay to the other side of the capacitor means and the relay contacts across the input of the circuit. In order to stabilize or smooth the output voltage from the circuit, a tank capacitor may be coupled across the output of the circuit and a second rectifier serially coupled in the circuit between the first rectifier and the adjacent output, to prevent bleeding-off of the stored charge in the tank capacitor. When the DC. voltage-doubler circuit of the invention forms part of a flasher circuit for flash tubes and the like, a trigger circuit including serially coupled capacitor and trigger coil means is coupled between the pole contact of the relay and one side of the input, so that the trigger circuit capacitor is alternately, successively charged and discharged through the trigger coil to repetitively flash the tube as the relay operates.

By utilizing a rectifier or other unidirectional conducting means in the DC. voltage-doubler circuit, a simple, single-pole, double-throw relay may be employed to switch the doubler capacitor rather than a complex double-pole, double-throw relay or vibrator as employed in the heretofore known arrangements. This permits the novel D.C. voltage-doubler circuit to be used in flasher circuits for beacon equipment and the like because of the attendant reduction in size, weight, cost and complexity of the equipment. Furthermore, by using the novel voltage-doubler circuit in beacon equipment, the equipment produces light flashes of higher intensity from the flash tube, even though batteries having low terminal voltages are employed as the source of direct voltage. Finally, since the energizing circuit for the single-pole, double-throw relay may be coupled to the battery source of direct voltage at the input of the circuit, the relay is self-synchronous in operation and the voltage-doubler, flasher circuit of the invention will continue to operate even though the battery voltage falls below the level required to ionize the flash tube. In the known flasher circuits, such as those employing A.C. voltage-doublers, for example, the voltage-doubling action ceases when the battery voltage falls below the threshold level of the doubler circuit, so that the beacon equipment fails completely. When the battery voltage falls after long periods of use in the flasher circuit of the invention, the charging rate for the doubler capacitor will decrease due to the increased effect of the battery impedance at the lower terminal voltage, so that the doubler capacitor may not be charged to the full battery voltage required to ionize the flash tube. However, whatever charge is placed in the doubler capacitor will be applied to the tank capacitor when the doubler capacitor is connected in series with the battery. Since the doubler capacitor will not be fully discharged into the tank capacitor, due to the difference in capacity, on the next charging cycle, the partially charged doubler capacitor will be charged to an even higher voltage level and will eventually approach battery terminal voltage. When the doubler capacitor reaches battery voltage, even at a reduced level, the tank capacitor will be charged to substantially double battery voltage. Accordingly, even though several charging cycles may be re quired to charge the tank capacitor to a voltage level which ionizes the flash tube, the beacon equipment will still continue to operate, although at a lower light intensity and reduced flash repetition rate, and to provide a rneasure of warning or signalling long after the heretofore known flasher circuits have become inoperative.

The single FIGURE of the drawing illustrates a pre ferred embodiment of the voltage-doubler, flasher circuit of the invention as employed, for example, to energize a xenon type of high intensity flash tube. As seen therein, the xenon flash tube has an envelope 10, an anode element terminal 11, a cathode element terminal 12 and a trigger element terminal 13. While the older types of xenon lamps usually required about 150 to 180 volts DC. for reliable operation, some of the newer types may operate with voltages as low as 100 volts D.C. With the proper voltage applied to the anode and cathode elements of the xenon tube, the tube will ionize and may be flashed by pulsing the trigger element with a 5 to k-v. trigger voltage. While a xenon type of flash lamp has been illustrated, it will be understood that any high voltage, discharge type of lamp may be employed with the circuit of the invention.

Referring again to the drawing, the anode element terminal 11 of the lamp is connected by a lead 14, rectifiers 15 and 16, and a resistor 17 to the positive terminal 18 of a battery 19. The cathode element terminal 12 of the flash lamp is connected by a lead to the negative terminal 21 of the battery, so that the terminal voltage of the battery is eflectively applied to the anode and cathode elements of the tube. It will be noted that rectifiers 15 and 16 are serially coupled with the battery input of the circuit across the output of the circuit and that the rectifiers are arranged in a forward conducting direction with respect to the battery source 19. In practice, the rectifiers 15 and 16 may be of the selenium type or may comprise germanium or silicon diodes, for example. If germanium or silicon diodes are employed, it may be necessary to increase the series resistance of the circuit, for example, by increasing the value of resistor 17, to insure arcless contact operation of the relay. The resistor 17 is a deionization resistor which is utilized to permit the xenon lamp to completely extinguish between flashes, when one of the newer, low impedance types of batteries is employed as the direct voltage source. The source of direct voltage, which is shown as the battery 19, is connected across the

input terminals

18 and 21 of the circuit. In practice, several types of batteries are employed, such as the military type BAl3l5/U mercury battery having a terminal voltage of approximately 129 volts, or the NEDA type 2111 battery having a terminal voltage of 67 /2 volts. When the latter type of battery is employed, two of them are placed in series circuit to provide a total voltage of volts across the

terminals

18 and 21.

A doubler capacitor 22 has one side thereof connected to the circuit junction between rectifiers 15 and 16 and the other side thereof connected to the pole contact 23 of a single-pole, double-throw relay 24-. The relay 24 may comprise any of the commercially available types, such as the Sigma type 5F16K, for example, and has a pair of relay contacts 25 and 26 and a relay coil 27. Relay contact 25 is connected to the positive terminal 18 of the battery by means of

leads

23 and 29, while relay contact 26 is connected to the negative battery terminal 21 by means of a lead 33. The energizing circuit for the relay comprises the relay coil 27, a resistor 31 and acapacitor 32 and is connected between relay contact 25 and pole contact 23 by means of

leads

28 and 30. The resistor 31 and capacitor 32 are serially coupled, with the capacitor 32 shunting the relay coil 27. The pole contact 23 of the relay is also connected by a lead 34 to one side of a trigger capacitor 35 which is connected in series circuit with a primary trigger coil 36. The other side of the trigger coil 36 is connected to the negative terminal 21 of the battery by means of lead 2%), as illustrated. A high voltage secondary trigger coil 37 is inductively coupled to the primary trigger coil 36 and is connected between the trigger element terminal 13 of the xenon lamp and the negative battery terminal 21. In practice, the turns ratio of the primary and secondary trigger coils is made sufficiently high to produce a 5 to 10 kv. trigger voltage for the trigger element of the lamp when the capacitor 35 is charged to battery voltage and subsequently discharged. Finally, a tank capacitor 38 having about one-third the capacity of doubler capacitor 22 is connected by a lead 39 across the output terminals 11 and 12 of the circuit to act as a storage capacitor to stabilize and smooth the output voltage from the circuit.

In order to describe the operation of the circuit, the relay 24 will be assumed initially to be in its deenergized position with the pole contact 23 in engagement with relay contact 26, as illustrated. Under these conditions, the positive terminal 18 of the battery is connected to one side of the doubler capacitor 22 through resistor 17 and rectifier 16 and the negative terminal 21 of the battery is connected to the other side of the doubler capacitor 22 by

leads

20 and 33, relay contact 26 and pole contact 23,

so that the capacitor is charged to battery voltage with the polarity illustrated. It may be noted that, at this time, the capacitor 22 is connected to shunt the serially coupled battery 19 and rectifier 16. At the same time, a circuit is closed from positive battery terminal 18 through lead 29, resistor 31, capacitor 32-, lead 30, pole contact 23, relay contact 26, lead 33 and lead 24} to the negative battery terminal 21. Since the capacitor 32 is initially uncharged with the pole contact in the position shown, it constitutes almost a direct short circuit across the relay coil 27, so that the relay is not energized. After a period of time determined by the circuit values of resistor 31 and capacitor 32, the charge on capacitor 32 builds up to a point where sufficient current is diverted through relay coil 27 to energize the relay 24 and move the pole contact 23 to engage relay contact 25. When this occurs, the doubler capacitor 22, which has been previously charged to battery voltage, is connected to shunt iectifier l6 and resistor 17 through a circuit formed by pole contact 23, relay contact 25, and leads 28 and 29. At this time, the charged capacitor 22 is serially coupled iii a voltage aiding direction with the battery 19 across the output terminals 11 and 12 of the circuit, so that the tank capacitor 38 is charged to approximately double the battery voltage. It may be noted that the rectifier 16 is in a blocking direction with respect to the capacitor and prevents the capacitor 22 from being discharged through the resistor 17. Similarly, the rectifier prevents the charge in tank capacitor 33 from being bled off. At this time, with the relay energized, the parallel-connected relay coil 2'7 and capacitor 32 are connected in a closed circuit with the resistor 31 by means of lead 30, pole contact 23, relay contact 25 and lead 28, so that the charge on the capacitor 32 is dissipated through the relay coil 27 and resistor 31 to hold the relay in its energized position for a period of time depending upon the circuit values of the components of the energizing circuit. When the charge on capacitor 32 has been sufficiently dissipated the relay coil 27 no longer acts to hold the pole contact 23 in engagement with relay contact 25 and the pole contact will return to deenergized position in engagement with relay contact 26, to thereby start another charging cycle. Accordingly, the energizing circuit of the relay 24 causes it to operate as a self-synchronous switch having a rate of operation depending upon the values of resistor 31 and capacitor 32. In determining the values of the circuit parameters of the relay energizing circuit, the value of resistor 31 should be made as high as possible consistent with minimum voltage operation. Also, for best voltage doubling operation, the energized time period of the relay should appropriately equal the deenergized time period.

By virtue of the above-described, self-synchronous operation of the relay, the doubler capacitor 22 is alternately, successively connected to shunt the rectifier 16 and to shunt the series combination of rectifier 16 and voltage source 19, so that a voltage of approximately double the battery voltage is built up across tank capacitor 38 and applied to the anode-cathode elements of the flash lamp. The relay action also repetitively triggers the Xenon lamp and produces repeated flashes of light therefrom. When the relay 24 is energized so that pole contact 23 engages relay contact 25, the trigger capacitor is charged by battery 19 through a circuit passing from positive battery terminal 18, leads 29 and 28, relay contact 25, pole contact 23, lead 34, capacitor 35, primary trigger coil 36 and lead 20 to negative battery terminal 21. Since, at the start of the charging cycle of capacitor 35, the capacitor is uncharged, the voltage applied to the primary trigger coil 36 rises almost instantaneously from zero to full battery voltage, so that a high voltage pulse is produced in secondary trigger coil 37 to flash the lamp. During the period the relay 24 is energized, the capacitor 35 becomes charged to full battery voltage and thereafter prevents further flow of current through primary trigger coil 36. When the relay 2 returns to its deenergized position, the capacitor 35 is connected in closed circuit with the primary trigger coil 36 by means of lead, 34, pole contact 23, relay contact 26 and leads 33 and 20, so that the capacitor 35 is discharged through the primary trigger coil 36 to produce another high voltage pulse in the secondary trigger coil 37 and, consequently, another flash of the lamp. Accordingly, the rate of operation of the relay 2&- determines the flash repetition rate of the flash lamp.

As mentioned previously, the flasher circuit of the invention will continue to operate even though the anodecathode voltage of the flash lamp falls below the threshold value necessary for ionization. After long periods of use, the terminal voltage of battery 19 will decrease so that the battery impedance becomes significant in limiting the charging rate of doubler capacitor 22. When this occurs, the doubler capacitor will not become charged to even the reduced battery voltage, but will be charged to a lower value. During the next portion of the cycle, when capacitor 22 is connected in series circuit with battery 19 across the tank capacitor 38, the combined battery voltage and the charge voltage on the doubler capacitor may be too low to permit the xenon lamp to ionize. Since the doubler capacitor is preferably at least three times larger than the tank capacitor, the doubler capacitor will not fully discharge into the tank capacitor. Accordingly, during the next charging cycle, the partially charged capacitor 22 may be charged to a value closer to the full battery voltage even though the battery still provides a reduced charging rate. Eventually, however, the doubler capacitor will be charged to substantially the level of the reduced battery voltage and the tank capacitor will be charged to substantially double the battery voltage to ionize the flash tube. While the reduced battery voltage will cause a decrease in the light intensity of the flashes from the tube and a reduced repetition rate of the flashes, it will not render the circuit totally inoperative as in many of the known arrangements. The light flashes of lower intensity and reduced repetition rate will still provide a substantial measure of warning or signalling operation.

Typical values for the circuit components of the flasher circuit of the invention for operation with xenon flash tubes and with battery terminal voltages ranging between and volts are given, by way of example, as follows:

Doubler capacitor 22 mfd., 150 volts. Timing capacitor 32 15 mfd.

Trigger capacitor 35 .03.05 mfd., 200 volts. Tank capacitor 38 40 mid, 300 volts. Deionization resistor 17 220 ohms, .5 watt. Timing resistor 31 150K ohms, .5 watt.

It is believed apparent that many changes could be made in the above-described invention and many seemingly diflerent embodiments of the invention constructed without departing from the scope thereof. For example, the battery source of direct voltage illustrated could be replaced by a suitably filtered pulsating D.C. source and different types of relays or flash lamps could be utilized without departing from the basic concept of the invention. Accordingly, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a voltage-doubler circuit having an input and an output, wherein said input is adapted to be coupled to a direct voltage source, the combination comprising unidirectional conducting means serially coupled in forward conducting direction with said input across said output; capacitor means having one side thereof coupled to the side of said unidirectional conducting means adjacent said output; and a single-pole double-throw relay for alternately successively coupling the other side of said capacitor means to one side of said input and to the other side of said input, whereby said capacitor means is adapted to be alternately successively charged by said direct voltage source through said unidirectional conducting means and serially coupled with said source in a voltage aiding direction across said output, to thereby substantially double the voltage from said source appearing across said output.

2. The combination claimed in claim 1, wherein said relay is self-synchronous, and has the energizing circuit thereof coupled to said input, so that said relay is adapted to be energized by said direct voltage source.

3. In a voltage-doubler circuit having an input and an output, wherein said input is adapted to be coupled to a direct voltage source, the combination comprising a pair of serially coupled unidirectional conducting means serially coupled in forward conducting direction with said input across said output; first capacitor means coupled across said output; second capacitor means having one side thereof coupled to the circuit junction between said pair of serially coupled unidirectional conducting means; and means for alternately successively coupling the other side of said second capacitor means to one side of said input and to the other side of said input, whereby said second capacitor means is adapted to be alternately successively charged by said direct voltage source through one of said unidirectional conducting means and serially coupled with said source in a voltage aiding direction across said output, to thereby substantially double the voltage from said source appearing across said output.

4. In a voltage-doubler circuit having an input and an output, wherein said input is adapted to be coupled to a direct voltage source, the combination comprising a pair of serially coupled rectifiers serially coupled in forward conducting direction with said input across said output; a first capacitor coupled across said output; a second capacitor having one side thereof coupled to the circuit junction between said pair of serially coupled rectifiers; and a self-synchronous, single-pole, doublethrow relay having the pole contact thereof coupled to the other side of said second capacitor, the relay contacts thereof coupled across said input and the energizing circuit thereof coupled to said input, whereby said second capacitor is adapted to be alternately successively charged by said direct voltage source through one of said rectifiers and serially coupled with said source in a voltage aiding direction across said output, to thereby substantially double the voltage from said source appearing across said output.

5. The combination claimed in claim 4, wherein the energizing circuit of said relay comprises a resistor and a capacitor serially coupled between said pole contact and one of said relay contacts, and a relay coil shunted across said last-named capacitor.

6. In a flasher circuit having an input adapted to be coupled to a direct voltage source and an output adapted to be coupled to the anode and cathode elements of a high intensity flash tube of the type having anode, cathode and trigger elements, the combination comprising a pair of serially coupled unidirectional conducting trneans serially coupled in forward conducting direction with said input across said output; first capacitor means coupled across said output; second capacitor means having one side thereof coupled to the circuit junction between said pair of serially coupled unidirectional conducting means; a trigger circuit including serially coupled trigger coil and third capacitor means having one side thereof coupled to one side of said input, said trigger coil means being adapted to be coupled to the trigger element of said tube to flash said tube; and means for alternately successively coupling the other side of said second capacitor means and the other side of said trigger circuit to one side of said input and to the other side of said input, whereby said second capacitor means is adapted to be alternately successively charged by said direct voltage source through one of said unidirectional conducting means and serially coupled with said source in a voltage aiding direction across said output, to thereby substantially double the voltage from said source ap- 8 pearing across said output, and said third capacitor means is adapted to be alternately successively charged and discharged through said trigger coil means, to thereby repetitively flash said tube.

7. The combination claimed in claim 6, wherein said last-named means comprises a self-synchronous, singlepole, double-throw relay having the energizing circuit thereof coupled to said input, the pole contact thereof coupled to the other side of said second capacitor means and to the other side of said trigger circuit, and the relay contacts thereof coupled across said input.

8. The combination claimed in claim 7, wherein the energizing circuit of said relay comprises a resistor and a capacitor serially coupled between said pole contact and one of said relay contacts, and a relay coil shunted across said last-named capacitor.

9. In a flasher circuit having an input adapted to be coupled to a direct voltage source and an output adapted to be coupled to the anode and cathode elements of a high intensity flash tube of the type having anode, cathode and trigger elements, the combination comprising a pair of serially coupled rectifiers serially coupled in forward conducting direction with said input across said output; a first capacitor coupled across said output; a second capacitor having one side thereof con,- pled to the circuit junction between said pair of serially coupled rectifiers; a trigger circuit comprising a third capacitor and inductively coupled primary and secondary trigger coils, said third capacitor and said primary trigger coil being serially coupled with one side thereof coupled to one side of said input, said secondary trigger coil having one side thereof coupled to said one side of said input and the other side thereof adapted to be coupled to the trigger element of said tube; and a selfsynchronous, single-pole, double-throw relay having the pole contact thereof coupled to the other side of said second capacitor and to the other side of said serially coupled third capacitor and primary trigger coil, the relay contacts thereof coupled across said input, and the energizing circuit thereof including a serially coupled fourth capacitor and resistor and a relay coil shunting said fourth capacitor coupled between said pole contact and the other side of said input, whereby said second capacitor is adapted to be alternately successively charged by said direct voltage source through one of said rectifiers and serially coupled with said source in a voltage aiding direction across said output, to thereby substantially double the voltage from said source appearing across said output, and said third capacitor is adapted to be alternately successively charged and discharged through said primary trigger coil, to thereby repetitively flash said tube.

10. The combination claimed in claim 9, which further comprises a deionization resistor included in the series coupling between said input and said pair of recti-fiers to aid in extinguishing said tube between flashes.

References Cited in the file of this patent UNITED STATES PATENTS 2,838,692 Richardson June 10, 1958 2,873,409 Most Feb. 10, 1959 2,901,671 Most Aug. 25, 1959

Claims

6. IN A FLASHER CIRCUIT HAVING AN INPUT ADAPTED TO BE COUPLED TO A DIRECT VOLTAGE SOURCE AND AN OUTPUT ADAPTED TO BE COUPLED TO THE ANODE AND CATHODE ELEMENTS OF A HIGH INTENSITY FLASH TUBE OF THE TYPE HAVING ANODE, CATHODE AND TRIGGER ELEMENTS, THE COMBINATION COMPRISING A PAIR OF SERIALLY COUPLED UNIDIRECTIONAL CONDUCTING MEANS SERIALLY COUPLED IN FORWARD CONDUCTING DIRECTION WITH SAID INPUT ACROSS SAID OUTPUT; FIRST CAPACITOR MEANS COUPLED ACROSS SAID OUTPUT; SECOND CAPACITOR MEANS HAVING ONE SIDE THEREOF COUPLED TO THE CIRCUIT JUNCTION BETWEEN SAID PAIR OF SERIALLY COUPLED UNIDIRECTIONAL CONDUCTING MEANS; A TRIGGER CIRCUIT INCLUDING SERIALLY COUPLED TRIGGER COIL AND THIRD CAPACITOR MEANS HAVING ONE SIDE THEREOF COUPLED TO ONE SIDE OF SAID INPUT, SAID TRIGGER COIL MEANS BEING ADAPTED TO BE COUPLED TO THE TRIGGER ELEMENT OF SAID TUBE TO FLASH SAID TUBE; AND MEANS FOR ALTERNATELY SUCCESSIVELY COUPLING THE OTHER SIDE OF SAID SECOND CAPACITOR MEANS AND THE OTHER SIDE OF SAID TRIGGER CIRCUIT TO ONE SIDE OF SAID INPUT AND TO THE OTHER SIDE OF SAID INPUT, WHEREBY SAID SECOND CAPACITOR MEANS IS ADAPTED TO BE ALTERNATELY SUCCESSIVELY CHARGED BY SAID DIRECT VOLTAGE SOURCE THROUGH ONE OF SAID UNIDIRECTIONAL CONDUCTING MEANS AND SERIALLY COUPLED WITH SAID SOURCE IN A VOLTAGE AIDING DIRECTION ACROSS SAID OUTPUT, TO THEREBY SUBSTANTIALLY DOUBLE THE VOLTAGE FROM SAID SOURCE APPEARING ACROSS SAID OUTPUT, AND SAID THIRD CAPACITOR MEANS IS ADAPTED TO BE ALTERNATELY SUCCESSIVELY CHARGED AND DISCHARGED THROUGH SAID TRIGGER COIL MEANS, TO THEREBY REPETITIVELY FLASH SAID TUBE.