US3240993A

US3240993A - Luminous tube sign flasher

Info

Publication number: US3240993A
Application number: US272266A
Authority: US
Inventors: Gordon M Bell
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1963-04-11
Filing date: 1963-04-11
Publication date: 1966-03-15
Anticipated expiration: 1983-03-15

Description

March 15, 1966 G. M. BELL LUMINOUS TUBE SIGN FLASHER 2 Sheets-Sheet 1 Filed April 11, 1965 1, ma 5 3 V w M G G. M. BELL March 15, 1966 LUMINOUS TUBE SIGN FLASHER 2 Sheets-Sheet 2 Filed April 11, 1963 INVENTOR. Gare/017 M 56/1, fig 7/. W

United States Patent 3,240,993 LUMDIOUS TUBE SIGN FLASHER Gordon M. Bell, Fort Wayne, Ind., assignor to General Electric Company, a corporation of New York Filed Apr. 11, 1963, Ser. No. 272,266 13 Claims. (Cl. 315-254) This invention relates generally to electrical apparatus for flashing gaseous discharge lamps. More particularly, the invention relates to an improved timing circuit arrangement for use in conjunction with switching devices, such as magnetic reed switches, used in apparatus for flashing gaseous discharge lamps.

In a commonly used arrangement for controlling the rate at which luminous gaseous discharge lamps are flashed on and off, a rotary type of switch is driven 'by a motor at a predetermined speed. Where the luminous gaseous discharge lamps are operated by single ballast transformer and are to be flashed in unison, the rotary switch is usually connected in the primary circuit of the ballast transformer, and the primary circuit is opened and closed to cause the gaseous discharge lamps operated by the ballast transformer to be flashed on and off. Although electromagnetic type of switches have been proposed for use in the secondary circuits of ballast transformer, such an arrangement utilizes a motor driven device to move a permanent magnet toward and away from the switch in order to actuate it. An arrangement of this type is described in US. Patent 2,844,764.

A disadvantage of systems employing motor driven devices for controlling the flashing rate is that the systems generally require periodic maintenance because of the moving parts. There is a need therefore for a timing circuit arrangement that does not require any moving parts to accomplish the timing function in an apparatus for flashing gaseous discharge lamps.

Accordingly, a general object of the present invention is to provide an improved apparatus for flashing gaseous discharge lamps, such as neon tubes, that is relatively easy to maintain.

A more specific object of the present invention is to provide an apparatus for flashing one or more luminous gaseous discharge lamps wherein a static timing circuit is utilized to control the rate at which the gaseous discharge lamp or lamps are flashed on and off.

These and other objects and advantages of the invention are achieved in one form of the invention in which I have provided a timing circuit for controlling the flashing interval of one or more gaseous discharge lamps wherein the timing circuit is energized and deenergized in response to the on and off condition of one of the gaseous discharge lamps. One of the gaseous discharge lamps, in effect, functions as a switching element to synchronize the timing circuit. The timing circuit actuates a magnetic reed switch to a closed condition after a desired interval that starts when the timing circuit is energized. Further, the magnetic reed switch is actuated to an open condition after a desired interval that starts when the timing circuit is deenergized. For this purpose, the timing circuit includes a control winding disposed on the magnetic reed switch. This control winding drives the reed switch to an open and closed condition in response to the rate at which a capacitor connected across the winding is charged and discharged to provide the pull-in and drop-out ampere turns required to actuate the reed switch.

The capacitor is charged through a voltage dropping impedance element connected in circuit with the gaseous discharge lamp to be flashed so that the charging current is supplied to the capacitor only when the gaseous discharge lamp is conducting current. This charging current is supplied to the capacitor through a rectifying element so that the capacitor is charged with unidirectional current. As the voltage charge on the capacitor builds up, the current through the control winding builds up to a point where the ampere-turns of the control winding provides the magnetomotive force required to close the magnetic reed switch. During the succeeding interval, when the switch is closed, the gaseous discharge lamp having the voltage dropping impedance element connected in circuit therewith is flashed off and presents essentially an open circuit condition in the circuit branch containing the lamp and the voltage dropping impedance ele ment. Consequently, during this interval no current is supplied to the capacitor, and the capacitor discharges current through an impedance element to the control winding. When the current through the control winding decreases to a level such that the ampere-turns of the control winding are insuflicient to hold the contacts in the closed condition, the switch opens, and the gaseous discharge lamp in the circuit branch containing the impedance element flashes on to start another flashing cycle.

In certain cases it may be desirable to use a normally closed switch rather than a normally open switch in carrying out my invention, and it will be appreciated that in such cases the voltage dropping impedance element is placed in the circuit branch containing the switching element. The capacitor as it is charged across the voltage dropping element then functions to open the switch, and the switch recloses as the capacitor is discharged, thereby providing a flashing cycle for the lamp. For example, a magnetic reed switch may have a permanent magnet associated with the switch so that the reed contacts are in a normally closed position. In an arrangement using such a switch the control winding of the improved timing circuit provides a magnetomotive force required to overcome the magnetomotive force of the permanent magnet in order to actuate the switch to the open position and the voltage dropping element is connected in series circuit with the magnetic reed switch.

The improved timing circuit arrangement is generally used in conjunction with a ballast transformer that provides the ballasting action and the starting and operating potentials for the luminous gaseous discharge lamps. With the improved arrangement one or more gaseous discharge lamps operated by a ballast transformer may be flashed at any desirable rate while one or more other lamps are operated at a steady luminuos output level. The timing circuit employs relatively maintenance-free static components and is relatively inexpensive to manufacture.

The subject matter which I regard as my invention is set forth in the appended claims. The invention itself, however, together with further objects and advantages thereof may be better understood by referring to the following description taken in connection with the accompanying drawings in which:

FIGURE 1 is a schematic circuit diagram of :an apparatus embodying one form of the invention in which the improved timing and switching circuit arrangement is adapted for flashing one gaseous discharge lamp on and oif and operating another gaseous discharge lamp at a steady light output level;

FIGURE 2 is a schematic circuit diagram of an apparatus embodying the invention wherein one gaseous discharge lamp is operated at a steady light output level and a pair of gaseous discharge lamps are alternately flashed on and olf; and

FIGURE 3 is a schematic circuit diagram of an apparatus embodying the invention wherein a normally closed reed switch is actuated by the improved timing and switching circuit arrangement.

Referring now more specifically to the circuit diagram shown in FIGURE 1, the apparatus is shown enclosed in a dashed rectangle and is adapted for operating a first gaseous discharge lamp L at a steady light output level and for flashing a second gaseous discharge lamp L at some preselected flashing rate. The requisite starting and operating potentials for the gaseous discharge lamps L and L are supplied by a ballast transformer T As is shown schematically in FIGURE 1, the transformer T includes a primary winding P and a high leakage reactance secondary Winding S inductively coupled with the primary winding P on a magnetic core 11. Magnetic shunts 12 are interposed between the primary winding P and the secondary winding S to provide a path for leakage flux. The magnetic shunts 12 provide a low reluctance path for the leakage flux and thereby increase the leakage reactance of the transformer T Such a shunt construction results in what is generally referred to as a high leakage reactance transformer. In a high leakage reactance transformer the secondary current is effectively limited, and such transformers are used for operating gaseous discharge lamps because of the inherent negative impedance characteristics of these lamps.

In order to energize the apparatus 10 a pair of leads or

terminals

13, 14 are provided for connection to a suitable alternating current supply. The gaseous discharge lamps L and L to be operated by the apparatus 10 are connected in circuit with the

leads

15, 16 and 17. It will be noted that gaseous discharge lamp L which is the flashing lamp, is connected in a circuit which includes a voltage dropping element resistor R Both the parallel circuit branch which includes the magnetic reed switch 22 and the parallel circuit branch which includes the lamp L and resistor R are connected in circuit with the gaseous discharge lamp L According to the improved switching and timing arrangement of the invention, the

terminals

20, 21 of a magnetic reed switch 22 are connected in circuit with

leads

16 and 17 across the flashing gaseous discharge lamp L In the magnetic reed switch 22 used in the illustrated embodiment of the invention, the

reed contacts

23, 24 were in a normally open position as shown. The

reed contacts

23, 24 are closed when the ampere-turns provided by a control winding or a coil 25 reach the pull-in value of the reed switch 22. At this point suflicient magnetomotive force is provided to cause the

reed contacts

23, 24 to close. The reed switch 22 reverts to its normally open position when the ampere-turns of the control winding 25 falls off below the drop-out value of the reed switch 22.

The type of reed switches which may be used in the practice of the present invention are comprised of two

reed contacts

23, 24 formed of a material, such as a nickeliron alloy, which has suitable magnetic characteristics. The

reed contacts

23, 24 may be plated with gold or silver in the contact area to provide a relatively low contact resistance. The

reed contacts

23, 24 are enclosed in a glass tubular envelope 19. The tubular envelope 19 may be evacuated and sealed or in some switch designs may preferably be filled with gas such as hydrogen or an inert gas.

In the embodiment of the invention which was actually reduced to practice, as will hereinafter be more fully described, the control winding 24 was wound on a small plastic bobbin 26 formed with a central opening in which the magnetic reed switch 22 was placed. The coil 25 was connected in circuit across a capacitor C and a resistor R which are part of a timing circuit which includes diode D and the voltage dropping resistor R An important aspect of the improved switching arrangement is that voltage dropping resistor R is connected in the circuit branch which includes the flashing gaseous discharge lamp L and which parallels the circuit branch which includes the magnetic reed switch 22. With the voltage dropping resistor R connected in this manner,

it will be appreciated that a current will flow through the voltage dropping resistor R to energize the timing circuit only when the gaseous discharge lamp L is flashed on. When gaseous discharge lamp L is flashed off it in effect causes an open circuit in the parallel circuit branch containing the voltage dropping resistor R and essentially no current flows through the voltage dropping resistor R During this interval capacitor C discharges through the resistor R and the control winding 25. The resistor R controls this discharge current. It will be appreciated that by varying the impedance in the path of the discharge current from capacitor C the interval that gaseous discharge lamp L is flashed off can be readily changed.

Turning now to FIGURE 2, I have shown therein an apparatus 30 which includes equivalent components as are shown in the apparatus 10 of FIGURE 1. The apparatus 10 of FIGURE 2, however, is adapted for operating one gaseous discharge lamp L at a steady output light level and for flashing a pair of lamps L and L Since the schematic circuit diagrams of the apparatus 10 of FIGURES l and 2 are the same and utilize equivalent components, I have employed the same reference symbols to identify the corresponding parts thereof.

It will be noted that the essential difference between the circuit diagram shown in FIGURES 1 and 2 is that an additional gaseous discharge lamp L is connected in circuit with lead 16 of the apparatus 10. The additional gaseous discharge lamp L flashes on when the

reed contacts

23, 24 of the switch 22 are closed. The gaseous discharge lamp L has a lower starting and operating voltage than the gaseous discharge lamp L Thus, when lamp L is flashed on, the parallel circuit branch voltage is in sufficient to sustain the electric discharge in lamp L and lamp L is flashed off. When the lamp L is flashed 01f, the current through the voltage dropping resistor R is interrupted, and capacitor C is discharged. In this embodiment of the invention the controlled discharge of capacitor C determines the interval during which lamp L is on and lamp L is off.

Having more specific reference now to FIGURE 1, the operation of the apparatus 10 will now be more specifically described. Apparatus 10 is energized by the power supplied to the ballast transformer T When ballast transformer T is energized the open circuit voltage is initially applied across gaseous discharge lamps L and L During the initial starting condition, the magnetic reed switch is in its normally open position, and the flashing gaseous discharge lamp L is ignited in series with the gaseous discharge lamp L that is to be operated at a steady output level. With lamps L and L ignited, lamp current will now flow through the dropping resistor R Consequently, current will flow in the timing circuit which includes diode D and the capacitor C and capacitor C is charged with a unidirectional current. After a finite time interval the capacitor C charges to the point where the magnitude of the current through the control winding 25 is such that the pull-in value for the reed switch 22 is reached. The

reed contacts

23, 24 close, and the secondary current of the ballast transformer T shunts the gaseous discharge lamp L thereby causing gaseous discharge lamp L to be flashed off.

When gaseous discharge lamp L is turned off, it does not support current flow. Thus, there will be no current through the voltage dropping resistor R The current to the control winding 25 is now sustained by the discharge current from the capacitor C When the discharge current falls off to a level such that the dropout ampere-turns of the magnetic reed switch 22 are reached, the

reed contacts

23, 24 break contact, and thereby cause gaseous discharge lamp L to flash on. The flashing cycle repeats itself at a frequency which is determined by the rate at which capacitor C is charged and discharged to actuate the switching

contacts

23, 24.

Apparatus 30 shown in FIGURE 2 operates in a substantially similar manner as the apparatus shown in FIGURE 1 but operates one gaesous discharge lamp L, at a steady output level and alternately flashes a pair of gaseous discharge lamps L and L When apparatus 30 of FIGURE 2 is energized, the open circuit voltage of the ballast transformer T is initially applied across lamps L and L and these two lamps are ignited. During the interval that gaseous discharge lamp L is turned on, current flows through the voltage dropping resistor R to start a charging cycle on the capacitor C of the timing circuit. When the charge on the capacitor C reaches a level such that control winding 25 provides the pull-in ampere-turns for reed switch 22, the switch is actuated to the closed position, and gaseous discharge lamp L now ignites. Gaseous discharge lamp L will extinguish because the voltage across the parallel circuit branch is insufficient to maintain its electric discharge. During the interval that gaseous discharge lamp L is turned off, the power to the timing circuit is cut off since the secondary current does not flow through resistor R The discharge current from capacitor C now flows through the control winding 25. When this current diminishes to a point where the ampere-turns of control winding 25 are at the drop-out value of reed switch 22, the reed switch 22 is opened to flash gaseous discharge lamp L off and to flash gaseous discharge lamp L on.

By way of a more specific exemplification of the invention, the apparatus 30 illustrated in FIGURE 2 was constructed and actually reduced to practice for operating a white neon tube L at a steady level and for alternately flashing a pair of red and green neon tubes L and L at a flashing rate of 100 times per minute. The following specifications of the circuit components used are given by way of an illustration of the invention:

Transformer T GE 9T61Y3024.

Primary winding P 457 turns of .0339 inch in diameter wire.

Secondary winding S 33,000 turns of .0031 inch in diameter wire.

Magnetic reed switch 23 Hamlin magnetic reed switch type DRVM1, rated at 50 volt-amperes,

5,000 volts.

Coil 25 25,000 turns of .002 inch in diameter w i r e, 7,500 ohms.

Capacitor C I microfarads.

Resistor R 2,200 ohms.

Diode D INS38.

The ballast transformer provided an open circuit voltage of 7,500 volts R.M.S. and a short circuit current of 30 milliamperes. A resistor R was not required since coil 25 provided 7,500 ohms, which Was suflicient to control the discharge of capacitor C Although the lamps L and L were flashed on and off at a rate of 100 times per minute, it will be understood that the circuit may be designed to flash the lamps at frequencies as low as 30 per minute. The flashing rate may be adjustably controlled using variable resistors instead of fixed resistors for the components R and R In FIGURE 3, I have illustrated an apparatus 40 embodying the invention in which a normally closed magnetic reed switch 41 is employed as the switching element in the improved switching and timing circuit arrangement. As is shown in FIGURE 3, the

reed contacts

42 and 43 are held in a normally closed position by a permanent magnet 44. The control winding 45 is operatively disposed on the reed switch 41. As in the other illustrated timing circuits the control winding 45 is connected in circuit across a timing capacitor C It will be noted that in the apparatus 40 shown in FIGURE 3 the voltage dropping impedance element R is connected in the parallel circuit branch containing the magnetic reed switch 41. When the

switch contacts

42, 43 are closed, current flows through the voltage dropping impedance element R and the capacitor C is charged through the diode D with a half wave rectified current.

The starting and operating potentials for lamps L L and L are provided by a ballast transformer T and are applied to the lamps by the output leads 46, 47, 48. The ballast transformtr T includes a primary winding P having leads 49 and 50 for connection to an alternating supply, a secondary winding 8; inductively coupled with the primary winding P on a magnetic core 51 and magnetic shunts 52 interposed between the primary winding P and the secondary winding S When transformer T is initially energized by connecting the terminal leads 49 and 50 in circuit with an alternating current supply, lamps L and L; will turn on, lamp L; having a lower ignition voltage than lamp L Current now flows in the parallel circuit branch which includes the reed switch 41 and the voltage dropping element R Also, a charging current is supplied during this interval to the capacitor C When the capacitor C is charged to a level such that the current in the control winding 45 provides suflicient ampere-turns to overcome the magnetic effect of the permanent magnet 44, the magnetic reed switch 41 is actuated to the open position. As a result, lamp L is turned off, and lamp L is turned on.

With the magnetic reed switch 41 in the open position, there is no current flow through the voltage dropping impedance element R and the capacitor voltage C and the ampere-turns of the control winding 45 will fall olf. At a certain point the permanent magnet 44 will again cause the

reed contacts

42, 43 to close. With the magnetic reed switch 41 in the closed position, another flashing cycle commences. Lamp L is now turned on, and lamp L is turned off.

An important advantage of the timing and switching arrangement utilized in the apparatus 40 of FIGURE 3 is that it is readily adaptable to flashing one gaseous discharge lamp on or off. If it is desired to flash only one gaseous discharge lamp, it is necessary only to connect output lead 47 in circuit with output lead 46, and connect the lamp to be flashed in circuit across the output leads 46 and 48.

From the foregoing description of the invention, it will be apparent that the only movable elements used are the

reed contacts

23, 24. Since the

reed contacts

23, 24 are hermetically sealed in an evacuated or an inert atmosphere, long life for these movable elements can be insured by proper switch design. The improved timing circuit in accordance with the invention does not employ any moving parts.

It will be understood that although the lamps are schematically shown in the illustrated embodiments of the invention as straight elongated tubes, the lamps may be formed in any desired shape or configuration as required in a particular application. Further, it will be apparent to those skilled in the art that many modifications may be made. Thus, the particular embodiments of the invention described herein are intended as exemplifications of the invention, and the invention is not limited thereto. It is intended therefore by the appended claims to cover all such modifications that fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An apparatus for flashing at least one gaseous discharge lamp from an alternating current source, said apparatus including a high leakage reactance transformer having a primary winding for connection in circuit with the alternating current supply and a secondary winding for connection in circuit with the gaseous discharge lamp to supply the starting and operating potentials for the gaseous discharge lamp, a switching element having a pair of magnetically operated contacts, a control winding operatively associated with said switching element contacts to provide the magnetomotive force required to actuate said switching element contacts, a capacitor connected in circuit across the control winding, a voltage dropping element connected in circuit with said capacitor, a rectifying means connected in circuit with said capacitor and said voltage dropping element to rectify the current supplied to the capacitor, and circuit means for connecting said switching element contacts and said gaseous discharge lamp in parallel circuit branches with said voltage dropping element being included in one of said circuit branches so that said capacitor is supplied with charging current when current flows in one of said circuit branches, said gaseous discharge lamp being flashed at a frequency determined by the rate at which said capacitor is charged and discharged to cause said switching element contacts to be actuated.

2. The apparatus set forth in claim 1 wherein said switching element is a normally open magnetic reed switch and said voltage dropping element is connected in series circuit relationship with the gaseous discharge lamp.

3. The apparatus set forth in claim 1 wherein said switch-ing element is a normally closed magnetic reed switch having a permanent magnet to hold said reed con tacts in a closed position and said voltage dropping element'is connected in series circuit with said switching element.

4. An apparatus for operating a luminous gaseous discharge lamp at a steady light output level and for alternately flashing a pair of luminous gaseous discharge lamps from an alternating current source, one of said flashing gaseous discharge lamps having a lower starting potential than the other, said apparatus comprising: a ballast transformer having a primary winding for connection to the alternating current source and having a high leakage reactance secondary winding inductively coupled with said primary winding, circuit means for connecting one of said pair of gaseous discharge lamps to be flashed in a first circuit branch and the other said lamps to be flashed in a second circuit branch connected in parallel circuit relation with the first circuit branch, and for connecting said parallel circuit branches in circuit with the gaseous discharge lamp to be operated at a steady light output level, a magnetic reed switch, a control winding o'peratively associated with said reed switch, a voltage dropping element, means for connecting said magnetic reed switch in said first circuit branch to place said reed switch in series circuit with the flashing gaseous discharge lamp having the lower starting potential and for connecting said voltage dropping element in circuit in said second circuit branch to place the voltage dropping element in series circuit relationship with the other flashing gaseous discharge lamp, a capacitor connected in circuit with said control winding, and circuit means connecting said capacitor in circuit with said voltage dropping element, said circuit means including a rectifying element to cause said capacitor to be charged with a unidirectional current when the gaseous discharge lamp in the second circuit branch is flashed on and the rate at which said capacitor is charged and discharged determining the frequency at which said pair of gaseous flashing discharge lamps are flashed on and off.

5. The apparatus set forth in claim 4 wherein an impedance element is connected in the discharge path of said capacitor to control the rate of discharge thereof.

6. An apparatus for operating a first gaseous discharge lamp at a steady output level and for flashing a second gaseous discharge lamp from an alternating current source, said apparatus comprising: a ballast transformer having a primary winding for connection in circuit with the al-' ternating current source and having a high leakage reactance secondary wind-ing, circuit means for connecting the first and second gaseous discharge lamps in series across at least a secondary Winding of the ballast transformer,

a switching element comprised of a pair of magnetic reed contacts, a control winding operatively disposed with respect to said switching element, said switching element being actuated in response to the ampere-turns of said control winding, a capacitor connected in circuit with said control winding, a voltage dropping resistance element connected in circuit with said capacitor, a rectifying means connected in circuit with said voltage dropping resistance element and said capacitor for supplying a unidirectional charging current to said capacitor, and circuit means for connecting said switching element and said second gaseous discharge lamp in parallel circuit branches with said voltage dropping resistance element being included in the circuit branch having said second gaseous discharge lamp, and said capacitor being charged with current only when the second gaseous discharge lamp is flashed on anddischarged when the second gaseous discharge lamp is flashed off there-by to vary the ampere-turns of said control winding to actuate the switching element.

7. In an apparatus for flashing a luminous gaseous discharge lamp from an alternating current source, said apparatus including means for supplying the starting and operating potentials for the gaseous discharge lamp, the improvement comprising: a magnetically actuated reed switch comprised of a pair of switching contacts, a control winding for actuating said contacts in response to the ampere-turns of said control winding, a capacitor connected in circuit with the control winding, a voltage dropping impedance element and a rectifying element connected in circuit with said capacitor for supplying a unidirectional charging current to said capacitor when current flows through said impedance element, circuit means for connecting said switching element and said gaseous discharge lamp in parallel circuit branches with said voltage dropping element being included in one of said branches, said capacitor being supplied with charging current when current flows in said one circuit branch and being discharged through said control winding when there is no substantial current flow in said one circuit branch thereby varying the ampere-turns of said control winding to actuate the magnetic reed switch.

8. The apparatus set forth in claim 7 wherein the switching contacts of said magnetic reed switch are normally in the open position and said voltage dropping impedance element is connected in series circuit with the gaseous discharge lamp.

9. The apparatus set forth in claim 7 wherein said switching contacts of said magnetic reed switch are in a normally closed position and said voltage dropping impedance element is connected in series circuit with said magnetic reed switch.

10. An apparatus for operating at least one gaseous discharge lamp at a steady light output level and for flashing at least one gaseous discharge lamp from an alternating source, said apparatus comprising: a ballast transformer for connection in circuit with the alternating current source to provide the starting and operating potentials for the gaseous discharge lamps, said transformer having a secondary winding for connection in circuit with the gaseous discharge lamps, a switching element comprised of a pair of switching contacts enclosed in a glass envelope, a control winding operatively disposed on said glass envelope, said switching contacts being actuated in response to the ampere-turns of said control winding, a capacitor connected in circuit with said control winding, a voltage dropping resistor connected in circuit with said capacitor, a rectifying means connected in circuit with said capacitor and said resistor, and circuit means for connecting said gaseous discharge lamp to be flashed and said switching contacts of said switching element in first and second parallel circuit branches, with said resistor being included in one of said parallel circuit branches, said capacitor being charged in response to the voltage developed across said resistor when current flows in said one circuit branch and being discharged when there is essentially no current flow therein to vary the ampereturns of said control winding thereby to actuate said switching element and flash one of the gaseous discharge lamps at a predetermined rate While the other gaseous discharge lamp is operated at a steady light output level.

11. The apparatus set forth in claim 10 wherein said switching element is a normally closed magnetic reed switch and said voltage dropping resistor is connected in series circuit relation with the magnetic reed switch.

12. The apparatus set forth in claim 10 wherein said switching element is a normally open magnetic reed switch and said voltage dropping resistor is connected in parallel 5 said capacitor to control the interval during which said one gaseous discharge lamp is flashed otf.

References Cited by the Examiner UNITED STATES PATENTS 7/1935 Gessford 315-488 2,509,005 5/1950 Lord 315183 GEORGE N. WESTBY, Primary Examiner.

S. D. SCHLOSSER, Assistant Examiner.

Claims

1. AN APPARATUS FOR FLASHING AT LEAST ONE GASEOUS DISCHARGE LAMP FROM AN ALTERNATING CURRENT SOURCE, SAID APPARATUS INCLUDING A HIGH LEAKAGE REACTANCE TRANSFORMER HAVING A PRIMARY WINDING FOR CONNECTION IN CIRCUIT WITH THE ALTERNATING CURRENT SUPPLY AND A SECONDARY WINDING FOR CONNECTION IN CIRCUIT WITH THE GASEOUS DISCHARGE LAMP TO SUPPLY THE STARTING AND OPERATING POTENTIALS FOR THE GASEOUS DISCHARGE LAMP, A SWITCHING ELEMENT HAVING A PAIR OF MAGNETICALLY OPERATED CONTACTS, A CONTROL WINDING OPERATIVELY ASSOCIATED WITH SAID SWITCHING ELEMENT CONTACTS TO PROVIDE THE MAGNETOMOTIVE FORCE REQUIRED TO ACTUATE SAID SWITCHING ELEMENT CONTACTS, A CAPACITOR CONNECTED IN CIRCUIT ACROSS THE CONTROL WINDING, A VOLTAGE DROPPING ELEMENT CONNECTED IN CIRCUIT WITH SAID CAPACITOR, A RECTIFY-