Abstract: An improved tapped-inductor boost converter for operating a gas discharge lamp is disclosed. The converter includes a pair of input terminals connected to a power source supplying an input voltage, a pair of output terminals for providing an output voltage greater than or equal to the input voltage to the lamp, or other load, a tapped-inductor having first and second windings, an active switch for controlling current flow through the first winding for variably controlling the output voltage, a passive switch for controlling current flow through the second winding, and a first capacitor. The converter further includes an arrangement for varying the clamping voltage at the active switch in response to variations in the output voltage and also includes a clamping capacitor for transferring energy stored in the leakage inductance of the tapped-inductor to the load for improved efficiency.

Abstract: A control circuit is disclosed that can be used to control the light intensity of a fluorescent lamp. A first embodiment of the control circuit includes one variable inductor and a plurality of fixed inductors. A switch is used to connect one of the inductors to the fluorescent lamp in parallel. The intensity of the light output from the lamp is varied either by adjusting the inductance of the variable inductor, or by switching between the fixed inductors. A second embodiment uses a variable capacitor in place of the variable inductor and uses fixed capacitors in place of the fixed inductors.

Abstract: A flashing warning light assembly of a type including a voltage source (s), a transformer gate (W), first and second storage condensers (C1 and C2), flash tube (B), an ignition circuit (T, Z), and an electrical switch (T1) in series with the first storage condenser which is controllable electrically. A monitoring circuit (R1, R2, V1) is further included which senses the charge voltage of the first storage condenser and compares it with a reference voltage, opening the electrical switch when the charge voltage exceeds the reference voltage. The apparatus of this invention provides a flashing warning light assembly which is easily and cost-effectively producible and which, while reliably igniting the flash tube, makes possible the influencing of energy or light intensity of produced light flashes.

Abstract: A strobe alarm circuit utilizing an optocoupler in the DC-to-DC converter portion of the circuit for repetitively connecting and disconnecting an energy-storing inductor across a DC power source. The light-emitting diode portion of the optocoupler is connected in parallel with a resistor connected in series with the inductor for continuously monitoring the current flowing through the inductor; when the inductor current has attained a particular value at which the voltage drop across the resistor is sufficient to turn on the LED, the switch portion of the optocoupler is turned on and disconnects the inductor from across the source. After a short interval determined by the parameters of the optocoupler and associated circuitry, the cycle is repeated.

Abstract: A lighting and flash device comprises a flash tube with a corresponding ignition device and at least two energy storage device units. The voltage of the energy storage device units is independently adjustable. When the voltage of the energy storage device units is accordingly divided, the resulting color temperature, in practice, is held relatively constant within allowable limits.

Abstract: An object of the invention is to provide a flash light control circuit by which a flash bulb is controlled to maintain a constant quantity of emitted light at each flash, in order to counter an insufficient exposure of a photographic object, caused by a gradual decrease of emitted light with the progress of exposures, for example, in photography with a camera on a multi exposure basis.The object is achieved by a flash light control circuit comprising a trigger circuit that impresses a trigger voltage onto a trigger terminal of the flash bulb and comprising a non-self hold type switching element connected to the trigger circuit, which is turned on for discharging energy stored in a main capacitor into the flash bulb for its consequent flashing, wherein there is provided a pulse generating circuit that impresses, onto a gate terminal of the switching element, continual pulse signals whose duty ratios increase gradually.

Abstract: The invention provides a brightness control circuit for a periodically flashing xenon lamp. The intensity of the flashing lamp may be selected in response to the selection of a reference voltage. The control circuit has a power source in series with a thristor for selectively controlling an application of a voltage from a power source to a xenon lamp. A capacitor is coupled substantially in parallel with the xenon lamp in order to apply a voltage across the lamp. A comparator is responsive jointly to a charge level on the capacitor and a reference voltage. The comparator switches on/off the thyristor so that the switching voltage may be selected by selecting the reference voltage, thereby selecting the intensity of the reference voltage. The flashing lamp in this particular application is part of an airport runway approach system.

Abstract: A system employing a stroboscopic light source permits an operator to remotely inspect and analyze high speed repetitive motion of machines. The system enables an operator to freeze motion or permit slow motion in either direction of moving parts in their natural environment. The system effectively shields the electronics incorporated in the light source by separating the electronics into sections and by utilizing a fiber optic cable to carry a control signal which control the firing of the flash lamp of the light source. In addition, the light source provides for control of the phase relationship between an external synchronization signal and a control signal which fires the flash lamp so that the timing of the flash can be controlled to stop a specific event in the cycle.

Abstract: An apparatus is provided for controlling the charging of a main capacitor of a flash unit. Comparison means detect the timing at which a voltage V across the main capacitor reaches a reference voltage V.sub.1, at which point a flash photograph can be taken. A timer detects whether a predetermined time period has elapsed since the voltage V across the main capacitor reached the reference voltage V.sub.1 so as to stop charging the main capacitor. When the voltage V across the main capacitor drops to the reference voltage V.sub.1, as a result of the phenomenon known as "spontaneous discharge", recharging of the main capacitor occurs and the above process is repeated. When the recharging of the main capacitor has been performed over a predetermined time period or a predetermined number of times, the charging of the main capacitor is stopped.

Abstract: The present invention discloses a means and method for preventing damage to electronic ballasts for high frequency lamps. In normal use lamps assume rectifying characteristics and generate direct current which interferes with the proper functioning of the system. In one aspect of the invention, a capacitor is used to prevent damage caused by this direct current. In another aspect of the invention, the capacitor also reduces the operating voltage of the lamps while preventing damage caused by the direct current. Another aspect of the invention gives added control of the filament voltage before and after the ignition of the lamps. In a further aspect of the invention, a capacitor is connected in series with the primary of the filament transformer to prevent damage caused by a short circuited secondary.

Abstract: A DC/AC converter for supplying two discharge lamps (12, 13). Two input terminals (4, 5) of the converter are interconnected by a series circuit comprising two switching elements (6, 7). A capacitor (8) connects one of the input terminals (4) to a common end (18) of two output circuits (17, 16, 15, 14; 23, 22, 21, 20), one of these output circuits (17, 16, 15,14) also is connected to a junction point (19) between the switching elements (6, 7). A second series circuit comprising two further switching elements (10, 11) is connected to the input terminals. The other output circuit is connected to a junction point (19.sup.a) between the two further switching elements. The converter thus can be readily used both for simultaneously supplying two lamps and for supplying only one lamp.

Abstract: In a power supply circuit for operating an electroluminescent (EL) element comprising a DC power supply, an inverter connected across the power supply, and the EL element connected to the inverter, an inductor is inserted between the inverter and the EL element wherein an AC voltage is applied from the inverter through the inductor to the EL element to emit light. Another EL operating circuit includes a DC power supply, an inverter, a transformer, and a bipolar capacitor connected in this order and an AC power output on a secondary winding of the transformer is applied to an EL element to generate light. Both the circuits enables a noticeable luminance increase and power saving.

Abstract: A power supply for intermittently energized loads, particularly gas discharge tubes employed as high intensity lights, has a pair of capacitances which are charged to a high voltage level to provide primary and secondary sources of anode voltage for the load. A coupling circuit impedes the discharge of the secondary anode voltage source capacitance when the primary anode voltage source capacitance is discharged through the load whereby a high voltage is present at the load, i.e., a discharge tube anode, immediately subsequent to the tube being extinguished thus reducing the time between successive firings of the tube. The current available for recharging the primary anode voltage source capacitance may also be increased during the time periods when the tube is being rapidly and repetitively fired.

Abstract: Ballast and starting circuits for controlling current and voltage applied to an electrical discharge lamp. The ballast circuits use diodes or other suitable means to divide the AC power into positive and negative currents. The ballast circuits use positive and negative capacitors which are charged by the divided AC line current. In some embodiments the positively charged capacitors are charged during positive portions of alternating current and discharged during negative portions of the alternating current. The negatively charged capacitors are charged during negative portions of the alternating current and discharged during positive portions. Transistors or other appropriate switching means are used to controllably conduct current from the positive and negative capacitors to the lamp in an asynchronous manner. Startup circuits are included for boosting the voltage applied to the lamp either manually or automatically upon startup.

Abstract: A circuit arrangement for starting and operating gas discharge lamps with current of higher frequency comprises an electronic ballast unit connected to a direct voltage input source (2). An electronic switching element (3), which is controlled by a control device (8), is connected in series with an inductive element (4), and the discharge lamp (5). The lamp current flows through the inductive element from which a voltage is derived which is supplied to the control device as a supply direct voltage supply via a rectifier (14) and a smoothing capacitor (16). A first connection terminal of the smoothing capacitor is connected through a first ohmic resistor (18) to a first terminal of the direct voltage input source and a second connection of the capacitor is connected through the lamp (5) to a second terminal of the direct voltage input source.

Abstract: An improved power supply circuit for supplying power to intermittently energized loads, such as gaseous discharge tube devices. Such power supply has a transformer wherein current flow in the primary winding is controlled by a first semiconductor device that in turn is controlled by a second semiconductor device. A feedback circuit coupled to the primary winding provides a signal for turn-off of the first semiconductor device when its turn-off is initiated by the second semiconductor device. A circuit portion connected between the primary winding and the second semiconductor device provides a signal to the second semiconductor device when it initiates a turn-off of the first semiconductor device. Such signal continues operation of the second semiconductor device until the turn-off signal from the feedback circuit is effective to turn-off the first semiconductor device serving to reduce power dissipated in the first semiconductor device.

Abstract: A strobe trigger pulse generator includes a power supply, an energy storage capacitor coupled to the power supply and a trigger pulse generator which intermittently energizes a trigger pulse transformer to ionize the gaseous interior of a strobe flash lamp. The trigger pulse generator includes a trigger capacitor coupled to the trigger pulse transformer. A trigger capacitor charging device is coupled between the power supply and the trigger capacitor to selectively direct a charging current to the trigger capacitor. The trigger capacitor discharge circuit is coupled to the trigger capacitor to periodically discharge the capacitor through the trigger pulse transformer to generate a high voltage trigger pulse. A charge path disabling circuit is coupled to the current flow path between the power supply and the trigger capacitor to control the charging current directed to the trigger capacitor.

Abstract: The DC to DC converter includes a coupled inductor having a primary winding and a feedback winding. A drive current regulator circuit receives a variable input voltage from the feedback winding but transmits a constant base drive current to the base terminal of the converter switching transistor. The base drive regulator circuit thereby enables the DC to DC converter to operate at high levels of efficiency over wide ranges of DC input voltages such as twelve to forty-eight volts DC.

Abstract: A strobe trigger pulse generator includes a power supply, an energy storage capacitorcoupled to the power supply and a trigger pulse generator which intermittently generates trigger pulses to energize a trigger pulse transformer. The pulse generator includes a trigger capacitor having first and second leads, the first of which is coupled to the trigger pulse transformer. A trigger capacitor charge circuit includes an input terminal coupled to the power supply and an output terminal coupled to the second lead of the trigger capacitor to establish a current flow path between the power supply and the trigger capacitor to direct a charge current to the trigger capacitor. A trigger capacitor discharge circuit is coupled to the second lead of the trigger capacitor to periodically direct a discharge current from the trigger capacitor through the trigger pulse transformer to generator a high voltage trigger pulse.

Abstract: An electric arrangement for igniting and supplying a gas discharge lamp (1). The arrangement is connected to an alternating voltage source and comprises a rectifier bridge (7) connected to a DC/DC converter provided with a rectifier element (11), a coil (10) and a high-frequency switched semiconductor switching element (12) coupled to a drive circuit. The DC/DC converter is connected to the input terminals (16, 17) of a high-frequency DC/AC converter incorporating the lamp and provided with semiconductor switching elements (21,24). A capacitor (15) is arranged between the input terminals of the DC/AC converter and a sensor (22) for measuring the converter current is arranged between one of the input terminals (17) and a semiconductor switching element (21) of the DC/AC converter. The lamp is connected in series with a frequency-dependent impedance 20.

Abstract: An improvement to the gas mixture used in diffuse glow discharge closing switches is disclosed which includes binary and ternary gas mixtures which are formulated to exhibit decreasing electron attachment with increasing temperature. This increases the efficiency of the conductance of the glow discharge and further inhibits the formation of an arc.

Abstract: A=n apparatus is provided for controlling the charging of a main capacitor of a flash unit. Comparison means detect the timing at which a voltage V across the main capacitor reaches a reference voltage V.sub.1, at which point a flash photograph can be taken. A timer detects whether a predetermined time period has elapsed since the voltage V across the main capacitor reached the reference voltage V.sub.1 so as to stop charging the main capacitor. When the voltage V across the main capacitor drops to the reference voltage V.sub.1, as a result of the phenomenon known as "spontaneous discharge", recharging of the main capacitor occurs and the above process is repeated. When the recharging of the main capacitor has been performed over a predetermined time period or a predetermined number of times, the charging of the main capacitor is stopped.

Abstract: A dimmer for a fluorescent light in which the fluorescent light is supplied with an electrical signal having a varying magnitude, the dimmer positioning a notch of reduced signal magnitude within the electrical signal for controlling the illumination level of the fluorescent light wherein the illumination level is dependent upon the position of the notch within the varying electrical signal.

Abstract: A heavy duty flasher for incandescent lamps for a motor coach or the like incorporates a pair of power MOSFETs in parallel for efficient, cool operation and includes a pair of timers, one for flash rate control and the other for producing AC for operating a voltage multiplier to provide gate voltage for the MOSFETs. Protective circuitry senses current overload and terminates current flow to protect the power devices while allowing inrush current to the lamps at the beginning of each cycle. A circuit sensitive to the presence of load supplies power to the timers only under load conditions.

Abstract: A low voltage electronic starter for an L-C Ballast of a fluorescent lamp is provided having a switching circuit having a resistive-capacitive network, a diac and triac, a transformer and a voltage multiplying rectifier.

Abstract: A circuit arrangement for operating a high-pressure gas discharge lamp (3) with a pulsatory direct current produced from an alternating voltage supply (A, B) via a full-wave rectifier (1). The output of the full-wave rectifier is shunted by a series arrangement of a diode (4) and a capacitor (5). The capacitor (5) has a value of 10 nF to 1 .mu.F and a resistor (6), which is high-ohmic with respect to a current limiter (2) in series with the lamp (3), is connected in a current circuit between the end of the capacitor facing the diode and the lamp (3). As a result, a low re-ignition voltage is attained during the head-up phase of the lamp.

Abstract: A series inverter, high voltage capacitor charging circuit includes current sensors for sensing the current through each SCR in the circuit. The sensed current is used to vary the gating frequency of the SCRs and to preclude firing of an SCR until the other is in a stable off condition. The gating of each SCR is delayed by an amuont of time determined by a control capacitor charging circuit. That charging circuit is inhibited as long as one of the SCRs is conducting and once the load voltage has reached a predetermined level. The time constant of that charging circuit can be changed as the desired level is approached of if insufficient reverse bias is applied to an SCR for quick turn-off of the SCR. Resolution of the system can be increased by a shunt regulator which shorts the output transformer. The circuit can be disabled if the high voltage capacitor does not reach its set level within a given time.

Abstract: A starting and operating circuit for high pressure discharge lamps including a pair of input terminals for connection to an alternating current supply and a pair of output terminals for connection across the lamp. A ballast inductor is connected at its ends in series between one of the input terminals and one of the output terminals and a pulse generator is connected between the output terminals. The pulse generator comprises a non-linear capacitor (NLC) and a semiconductor bipolar thyristor (commonly known as a SIDAC) connected in series, the non-linear capacitor and bipolar thyristor being connected in parallel with the discharge lamp.

Abstract: The converter delivers current to an intermittently energized load and includes a coupled inductor having a primary winding, a secondary winding and a feedback winding. A switching transistor is coupled in series with the primary winding of the inductor and switches between conductive and non-conductive states to control the flow of current through the primary winding. A positive drive circuit provides positive bias voltage to the switching transistor. A current limiting circuit senses the voltage across the base-emitter junction of the switching transistor to measure the primary winding current, removes the positive bias voltage when the primary winding current reaches a predetermined value, and thereby switches the transistor out of the conductive state into the non-conductive state.

Abstract: High pressure xenon is used as a buffer gas in an electrodeless sodium iodide arc lamp. Very high efficacies are achieved by using an arc tube with rounded edges and by surrounding a portion of the arc tube with quartz wool. The arc tube may also contain small amounts of mercury iodide.

Abstract: A high-pressure sodium discharge lamp comprising a discharge vessel (3) provided with an external auxiliary electrode (11) and a built-in electric starting circuit including an electric circuit comprising a transformer winding (35a), a capacitor (33) and a semiconductor switching element (34). The circuit is connected in series with a resistor (32) electrically parallel to the discharge vessel (3) and with the transformer (35) electrically connected to the external auxiliary electrode (11). The semiconductor switching element (34) is an uncontrolled voltage-dependent breakdown element of the thyristor type having a breakdown current smaller than 1 mA at a breakdown time shorter than 10 .mu.s. The resultant lamp starts very reliably and its build-in starter dissipates only a very low power.

Abstract: This invention is directed to an improved low voltage fluorescent lighting system having two elongated fluorescent lamps. The invention provides an improved simple switching system which allows one or both lamps to be turned on. The improved switching system includes a high capacitance by-pass circuit parallel to one of the fluorescent lamps which, when closed, by-passes sufficient current so that the lamp in parallel will not be lit.

Abstract: A panoramic light emitter of an omnidirectional horizontal light beam with very sharp cut-off in the vertical plane is disclosed. The sharp cut-off prevents interference near airports. High average powers are attainable because the light source can be distributed rather than be a point source. The omnidirectional-in-the-horizontal-plane light emitter with a high degree of vertical beam control is achieved by combining a generally cylindrical refractor with an internally emitting open-ended generally conical light source. The internal emitting surface of the conical light source is in the focal plane of the cylindrical refractor. The refractor sharply images the source with its edges, and that image is projected panoramically as the light beam having sharp cut-off at the edges of the image. The external surface of the conical light source does not emit, thus preventing undesired angles of light from passing out through the refractor.

Abstract: A load is provided, at all times when in operation, with a D.C. voltage having at least a minimum holding magnitude by: providing a source voltage having a peak magnitude greater than the holding magnitude; connecting the source voltage to the load only while the source voltage magnitude is greater than a preselected magnitude; charging from the peak source voltage magnitude an energy storage element while the load is connnected to the source voltage; energizing the load from the charged energy storage element whenever the source voltage magnitude is less than the preselected magnitude; increasing the effective impedance of the load whenever the load is energized by the storage element; and selecting the energy storage element to provide at least the holding voltage to the load during each time interval when the energy storage element is connected to the load.

Abstract: An improved high power (40,000 watt) high intensity arc discharge power supply which provides reliable, automatic ignition control and enables precise variation of lamp power in dual AC and DC modes of operation over an extended dynamic range from 400 watts to 40,000 watts. A capacitive boost circuit is provided to supply the high voltage necessary to ignite the lamp. Upon start-up, the voltage on a boost circuit capacitor is monitored by an ignition circuit which automatically enables the ignitor when the voltage is at the required level and switches the ignitor off when the lamp starts. After ignition the boost charging circuit is disabled and the power supply operates in a normal mode. The power supply operates on a three phase alternating voltage input through a three phase bridge, switches it through a drive transistor and then supplies it to an inductor. The signal is then supplied through an H-bridge commutator to the boost circuit, the ignitor and the arc lamp itself.

Abstract: A light source including a spiral line pulse generator having an output coupled to one electrode of a high pressure discharge lamp and having an input for coupling to a source of lamp operating power for providing high voltage lamp starting pulses. This pulse generator includes, in addition to a spiral line generator, a solid state electronic switch in combination with an inductor. The electronic switch and inductor are connected in series between the conductors of the spiral line pulse generator for multiple discharge of the spiral line pulse generator to provide multiple high voltage pulses during each half cycle of lamp operating power to initiate discharge in the high pressure discharge lamp.

Abstract: A power supply is provided for an arc discharge lamp (38) which includes a relatively low voltage high current power supply section and a high voltage starter circuit (10). The low voltage section includes a transformer (15), rectifier (24), variable resistor (26) and a bank of capacitors (28), while the starter circuit (10) comprises a plurality of diodes (D1 to D12) and capacitors (C1 to C12) connected as a Cockcroft-Walton multiplier. The starting circuit is effectively bypassed when the lamp arc is established and serves to automatically provide a high starting voltage to re-strike the lamp arc if the arc is extinguished by a power interruption.

Abstract: An optical cleaning system for removing matter from underwater surfaces comprising the high energy strobe lamp, a capacitor electrically connected to the strobe lamp, a power supply electrically connected to the capacitor, and a trigger circuit electrically interactive with the capacitor. The strobe lamp is either a xenon or krypton lamp. Stainless steel reflectors are arranged about the strobe lamp so as to reflect and direct light. The power supply is a generator having a capacity of less than 5 kilovolts. The optical cleaning system may further comprise a cooling fluid and a cooling fluid circulation system in heat exchange relationship with the strobe lamp. The trigger circuit is a transformer electrically connected in series with the capacitor and a switch for actuating the transformer. The optical cleaning system further includes a remotely controlled manipulator arm for positioning the strobe lamp in position about the area to be cleaned.

Abstract: A circuit for repetitively firing a flash or strobe lamp with voltage derived from the AC line without large and costly storage capacitors utilizes a voltage doubler having small capacitors one microfarad in capacitance value or less. A trigger circuit provides a high potential pulse to the trigger electrode of the lamp at or near the peak of the voltage from the AC line to provide flashes at a desired rate, say one per second. The circuit may be used in a warning light device.

Abstract: A light source including a spiral line pulse generator having an output coupled to one electrode of a high pressure discharge lamp and having an input for coupling to a source of lamp operating power for providing high voltage lamp starting pulses. The pulse generator includes, in addition to a spiral line circuit, a solid state electronic switch for discharging the spiral line pulse generator and a ballast capacitor connected in series with the solid state switch. The spiral line pulse generator preferably has a magnetic core associated therewith for increasing the spiral line inductance.

Abstract: The present invention consists of a modulation circuit used in a digital application. The modulation circuit is designed to provide an LED with a more analog type signal. This in turn causes the LED to emit a signal that is peaked rather than a constant square wave providing a better conversion frequency to the fundamental frequency.

Abstract: A strobe light firing circuit is provided with an integrated circuit (10) for deriving both timing and power generating pulses. A field-effect power transistor (16) gates the power generation transients while effectively isolating the timing integrated circuit (10) from high transients during the switching of the transistor (16). Timing pulses from the timing circuit (10) are divided in frequency by a binary counter (38) and then sequentially applied at the output pins of a decade counter (40) for strobe timing sequence selection. A strobe light firing pulse is differentiated (48) to form a pulse for shutting off power generation pulses from time (10) for a time effective for the flash tube (58) to recover for a subsequent discharge.

Abstract: A low wattage metal vapor discharge lamp starting and operating apparatus includes an inductive ballast connected to one of a pair of terminals connectable to a low voltage source, a metal vapor discharge lamp coupled to the ballast and to the other one of the pair of lamp terminals and a non-linear dielectric element shunting the discharge lamp with the ballast and non-linear dielectric element providing a potential within about 600 usec of current reversal of the source voltage in an amount sufficient to initiate operation of the discharge lamp.

Abstract: A series inverter, high voltage capacitor charging circuit includes current sensors for sensing the current through each SCR in the circuit. The sensed current is used to vary the gating frequency of the SCRs and to preclude firing of an SCR until the other is in a stable off condition. The gating of each SCR is delayed by an amount of time determined by a control capacitor charging circuit. That charging circuit is inhibited as long as one of the SCRs is conducting and once the load voltage has reached a predetermined level. The time constant of that charging circuit can be changed as the desired level is approached of if insufficient reverse bias is applied to an SCR for quick turn-off of the SCR. Resolution of the system can be increased by a shunt regulator which shorts the output transformer. The circuit can be disabled if the high voltage capacitor does not reach its set level within a given time.

Abstract: In a circuit for an inductively stabilized discharge tube (1) provided with two preheatable electrodes (2, 3) the ends of one electrode (2) are connected via a first capacitor (22) and a second capacitor (24), respectively, to the corresponding ends of the other electrode (3). The second capacitor (24) remote from the supply is shunted by a PTC resistor (23). The discharge tube (1) and inter alia the PTC resistor (23) form part of a lamp unit. The discharge tube (1) ignites readily even at low ambient temperatures. In the lamp operating condition, the influence of the PTC resistor (23) is neglible.

Abstract: A source of high-frequency voltage is applied directly across a series-resonant L-C circuit. A fluorescent lamp and a Varistor are both connected in parallel with the capacitor of this L-C circuit. The Varistor is operative: (i) to prevent the series-resonant L-C circuit from ever overloading the voltage source, and (ii) to limit the magnitude of the voltage provided across the lamp to a level appropriate for rapid-starting thereof. When power is initially applied, the lamp's cathodes are cold and the lamp does not conduct; which implies that a significant amount of power is dissipated in the Varistor. For sake of cost-effectivity and energy conservatiion, if the lamp fails to conduct for about 25 milli-seconds, a control means provides a short circuit across the capacitor. The resulting short circuit current is used for heating the fluorescent lamp cathodes. After about 1.

Abstract: A highly efficient circuit for converting a low level DC voltage to the high voltage necessary for energizing a flash lamp. The circuit is very small and non-complex, it is portable and is quickly recharged, particularly being adaptable for emergency flash uses and for toys such as light swords and laser pistols. A very efficient portion of the circuit, comprising a DC/AC inverter, an AC/DC converter and a voltage multiplier, operating at an appropriate frequency, enables the flash capacitor to always be maintained substantially at peak voltage value with minimum power usage.

Abstract: A current limited strobe charging circuit in which the charging current is automatically limited during the time required to reform the primary storage capacitor after a long period of non-use without materially effecting the current flow and time required to subsequently recharge the storage capacitor after it has been reformed includes a positive temperature coefficient resistor serially connected therewith to switch from a low resistance mode of operation to a high resistance mode of operation as a result of its own internally generated I.sup.2 R heat.

Abstract: A flash strobe power supply adapted for controlling alternately the energization of a pair of flash lamps includes a trigger timing device for generating a series of positive pulses and a series of negative pulses spaced in time from the positive pulses by a predetermined interval. First and second energy storage devices are provided for repeatedly charging incrementally during successive charging cycles and for storing a charge to be applied to respective first and second flash lamps. An inverter oscillator circuit includes a pulse width modulator and a transformer for generating a quasi-squarewave signal whose frequency is greater than the frequency of the positive and negative pulses to control the incremental charging of the energy storage devices. First and second switching devices deliver when conductive the charge stored in the first and second energy storage devices to their respective first and second flash lamps.

Abstract: A capacitor is charged to a high voltage, and then is discharged through a circuit comprising an analytical spark gap and first and second inductive elements, whereby the discharge current is oscillatory. The waveform of the discharge current is modified by a diode rectifier shunted across the series combination of the analytical spark gap and the second inductive element. To provide for adjustment of the waveform over a wide range, the second inductive element is adjustable in inductance. The first inductive element is also preferably adjustable in inductance. Provision may also be made for changing the capacitance of the capacitor. A reversing switch makes it possible to reverse the polarity of the diode rectifier. One or more control spark gaps may be connected in series with the analytical spark gap. An electronic switching device may be connected across one of the control spark gaps to initiate the discharge of the capacitor.