Abstract: An improved general service incandescent lamp having an improved capacitive ballast circuit for operating a low voltage filament of the lamp is disclosed. Various embodiments of an improved capacitive ballast circuit that substantially eliminates unwanted stored energy and unwanted resistive dissipation are disclosed.

Abstract: A high frequency ballast circuit is provided having first and second power input terminals and first and second power output terminals. The high frequency ballast circuit is powered by an input voltage source, such as an off-line, filtered, rectified dc voltage source. The high frequency ballast circuit has a starting mode and operating mode. The high frequency ballast circuit comprises: a power oscillator circuit having power oscillator first and second output terminals, for converting power coupled from the high frequency ballast circuit first and second power input terminals to a relatively high frequency, quasi-sinusoidal, current-limited voltage source applied between the power oscillator first and second output terminals. A starting circuit for interposing a periodic voltage pulse between the power oscillator first output terminal and the lamp load. The periodic voltage pulse is adapted to exceed the ionization potential of the lamp load during the starting mode.

Abstract: A driving system for a plasma panel display which uses VFETs for output switches controls the transition time of an output waveform to a constant time. Transformerless circuitry for communicating low voltage digital logic signals across a floating boundary to VFET control circuitry is provided. Low voltage control circuitry is isolated from high voltage sources by semiconductor circuitry which eliminates the need for transformer isolation techniques. In an alternative embodiment, the transition of an output waveform is controlled at a constant slew rate.

Abstract: A rapid start circuit for starting and step dimming a fluorescent lamp includes a voltage step up auto transformer and lamp filaments for starting, ballast and a pair of capacitors having different values variously connected in series with the lamp and ballast by a rotary switch; first in parallel, then individually and then in series to achieve a progressively stepped dimming of the lamp. A second form of the invention includes a first capacitor in series with the lamp and ballast for reducing the maximum light output of the lamp and a plurality of capacitors each having a different value selectively connected in parallel with the first capacitor by a slide switch to selectively dim the lamp; and a resistor in series with the first capacitor to diminish arcing and noise when switching. Both forms of the invention include a pair of secondary windings for maintaining filament voltage.

Abstract: A high efficiency pulsed ultraviolet light source is provided which comprises a flashlamp containing a noble gas, for example xenon, at low pressure, and having a pair of electrodes between which a discharge through the gas may be impressed, and an electrical pulse forming circuit connected to the flashlamp comprising a lamp resistance and high voltage source connected in series with the lamp, and a capacitor and switch connected in parallel to the lamp, the capacitor and resistance selected to minimize the total inductance of the circuit and to maximize the voltage stress on the gas contained within the lamp.

Abstract: A capacitively ballasted low voltage lamp comprising a main capacitor connected electrically in series with the lamp, across an alternating current source, and one or more auxiliary capacitors that can be connected electrically across the main capacitor by switching means for one or more source waveform cycles. The minimum lamp current is established by the main capacitor, with additional lamp current flowing through one or more auxiliary capacitors during one or more source waveform cycles.

Abstract: A capacitively ballasted low voltage lamp utilizing a main capacitor connected electrically in series with the lamp, across an alternating current source, and one or more auxiliary capacitors that can be connected electrically across the main capacitor by switching means for one or more source waveform cycles. Each switching means comprises a unidirectional conductive device electrically connected in parallel with an active switching device. The minimum lamp current is established by the main capacitor, with additional lamp current flowing through one or more auxiliary capacitors during a source waveform cycle or integral multiples thereof.

Abstract: A photographic flash device comprising a grip portion and a flash unit removably attachable thereto. Both the grip portion and flash unit house battery-powered DC-DC converters which cooperate upon attachment of the flash unit to the grip portion in charging a main discharge capacitor. A source switch permits charging of the discharge capacitor by only one of the DC-DC converters, and a safety switch prevents operation of at least one of the converters when the flash unit is not attached to the grip portion.

Abstract: An electronic ballast circuit for a lower pressure lamp wherein a voltage divider network coupled by a capacitor and directly coupled to an AC source is shunted by a series connected transistor switch and capacitor filter, and the switch is coupled by a diode to a lamp while a ballast resistor couples the filter capacitor to the lamp. A starter network device includes a glo-bottle starter which couples a transistor switch to the lamp with a resistor coupled to the glo-bottle starter and the transistor switch.

Abstract: The specification discloses a capacitive ballast for operating a gas discharge lamp from a conventional low frequency power source. The effective restart voltage during each cycle is enhanced by a trigger capacitor or pulse transformer which functions to produce a short duration reignition current. Properly timed, the reduced lamp voltage caused by the injection of the reignition current will be approximately equal to the difference between the instantaneous potential of the power source at the time of reignition and the instantaneous magnitude of the voltage across the ballast capacitor. The proper magnitude of lamp current is thus re-established during each half cycle and thereafter sustained at a value which equals the rate of change of voltage across the ballast capacitor.

Abstract: In a circuit for the operating of gas discharge lamps in which a starting circuit (2, 17) having a starter transformer (17) and a source of auxiliary voltage which can be disconnected after starting has been effected are provided for the starting of the lamp, there is provided a full-wave rectifier (6) with which a charging capacitor (10) and a voltage-dependent electronic switch element (8) are connected in parallel. A switch contact (9) which is in series with the charging capacitor (10) can be actuated by the switch element (8). The charging capacitor (10) which supplies the operating voltage for the gas discharge lamp (3) can be charged to a voltage which can be selected by means of the switch element (8). The full-wave rectifier (6) which serves a source of auxiliary voltage can be disconnected by means of a control element (4) from the gas discharge lamp (3) after the latter has been started.

Abstract: High voltage transients are effectively clamped by means of a spark gap, in parallel connection with a load to be protected, and having a capacitor in series with the parallelled load-spark gap combination. The series capacitor limits follow-through current through the spark gap to a level permitting survival of the spark gap. Where the load is an incandescent lamp, the spark gap is formed by shaping the lamp internal lead structure, such that an additional external spark gap component is not required.

Abstract: A variable illumination flash apparatus includes a main capacitor in parallel with a flash lamp and power source for normally supporting triggered discharge illumination of the lamp. A plurality of secondary circuits each containing a series-connected silicon controlled rectifier and secondary capacitor are disposed in parallel with the main capacitor and are individually selectively actuatable to store additional electric charge for further supporting lamp illumination. Each secondary circuit is actuated only when additional illumination is required for a subequent flash operation, thereby promoting efficient conservation of the power source in that no power is drawn from the source and stored in the capacitors unless needed for the immediately subsequent flash operation.

Abstract: A lightweight, transistorized, inverter circuit is particularly adapted for starting and operating a screw-in compact fluorescent lamp intended for incandescent lamp replacement. Household-type AC is converted to DC with one terminal connected to the center tap of a transformer primary through a choke which constitutes a high impedance at the operating frequency. A tuned circuit capacitor is connected across the transformer primary and a current-limiting capacitor and the lamp to be operated are connected in series across the transformer primary. A pair of transistors are connected in push-pull arrangement between the end portions of the transformer primary and the other terminal of the DC source, with the base electrodes of the transistors connected to the transformer secondary winding so that the push-pull connected transistors oscillate at the tuned circuit resonant frequency which is determined by the inductance of the transformer primary winding and the total capacitance of the connected capacitor means.

Abstract: A power supply, operating at line frequencies, for energizing a low-voltage lamp and like loads, utilizes a main capacitor in series with the load across the A.C. line source, and an auxiliary capacitor connected across the main capacitor by a switching device during a selected portion of the source waveform cycle. The minimum load current is established by the main capacitor, with additional load current flowing through the auxiliary capacitor during those portions of the source waveform cycle when connected, whereby the load current may be adjusted over a range established by the magnitude of the main and auxiliary capacitors. An open-loop circuit is disclosed for controlling the portion of the cycle during which the auxiliary capacitor is connected.

Abstract: A power supply providing power to a low voltage lamp utilizing a main capacitor connected electrically in series with the lamp, across an alternating current source, and an auxiliary capacitor connected electrically across the main capacitor by a switching device during selected portions of the source waveform cycle. The minimum lamp current is established by the main capacitor, with additional lamp current flowing through the auxiliary capacitor during portions of the source waveform cycle when the auxiliary capacitor is electrically connected across the main capacitor. The load current is adjusted over a desired range established by the magnitude of the main and auxiliary capacitors.

Abstract: Supply device for a flash tube comprising a capacitor, a d.c. voltage source connected to the capacitor, an energy switch located between the capacitor and the flash tube, a circuit able to emit a control pulse for the said switch and a preionization circuit for the flash tube, wherein the preionization circuit comprises a second energy switch connected to the capacitor across a variable resistor, as well as to the flash tube, and a second circuit able to emit a control pulse for the second switch, said second pulse being in advance of the first pulse.Application to the optical pumping of lasers.

Abstract: Incandescent lamp driver circuit with current surge limiting and built-in test features.

Abstract: A switching system for delivering pulses of power from a source (10) to a load (20) using a storage capacitor (C3) charged through a rectifier (D1, D2), and maintained charged to a reference voltage level by a transistor switch (Q1) and voltage comparator (12). A thyristor (22) is triggered to discharge the storage capacitor through a saturable reactor (18) and fractional turn saturable transformer (16) having a secondary to primary turn ratio N of n:l/n=n.sup.2. The saturable reactor (18) functions as a "soaker" while the thyristor reaches saturation, and then switches to a low impedance state. The saturable transformer functions as a switching transformer with high impedance while a load coupling capacitor (C4) charges, and then switches to a low impedance state to dump the charge of the storage capacitor (C3) into the load through the coupling capacitor (C4).

Abstract: An electric spark type light source for producing light for spectroscopic analysis, comprising an analytical spark gap, an energy storage capacitor, a charging and discharging circuit for alternately charging the capacitor and causing the capacitor to discharge across the spark gap to generate sparks which produce light for spectroscopic analysis, such circuit including at least one inductance coil for causing the discharge current through the spark gap to be oscillatory and pulsating in waveform, the circuit including rectifier means for causing the discharge current through the spark gap to have at least a unidirectional component, and time gate pulse generating means for deriving time gate pulses from the circuit in synchronized relation with the oscillatory pulsating spark gap current for use in selecting repetitive segments of the light from the sparks for spectroscopic analysis. The time gate pulses may be derived from the rectifier current, the capacitor discharge current or the spark gap current.

Abstract: In an electronic flash device of the type in which depending upon the exposure conditions an electronic flash lamp converts into light the energy stored on a main flash capacitor or the energies stored not only on the main flash capacitor but also on an auxiliary flash capacitor, a switching element which is turned on or off so as to permit or interrupt the discharge of the auxiliary flash capacitor is controlled by a simplified control circuit comprising a switching element control circuit which delivers a low voltage supplied from a low-voltage power source to the switching element as a turn-on signal and a detection circuit which controls the switching element control circuit in response to the exposure conditions such as a distance to a subject or a selected aperture. Therefore, an inversion circuit which is used in the prior art electronic flash devices can be eliminated.

Abstract: A safety switch arrangement is provided for an electronic flash for automatically discharging the main storage capacitor in response to the user deliberately or inadvertently removing the cover from the flash housing. The electronic flash is of any ordinary type comprising a DC-to-DC converter with a step-up transformer and the safety switch arrangement is connected to discharge the main storage capacitor through the secondary winding of the DC-to-DC converter transformer thereby eliminating the need for a separate bleeder resistor.

Abstract: A fluorescent lampholder fitting has a fluorescent lamp having first and second ends respectively provided with starting filaments. The lamp is supported by a housing which also encloses a solid-state fluorescent ballast and which also incorporates a male screw base electrical connector for supporting the housing in a portable lamp or lighting fixture. The male screw base is provided with three electrical input connections so configured to be electrically connected and selectively switched when installed in a three-way lampholder of the portable lamp or lighting fixture. The lampholder fitting is provided with a center-tapped step-down transformer which has three terminals attached to the three respective connections of the three-way male screw base. The step-down transformer has a single low-voltage secondary winding which connects to the input terminals of a full-wave bridge rectifier which has its rectified output connected to a high frequency oscillator.

Abstract: A starter circuit for a high power discharge lamp connected to an AC source via a series inductor. The starter circuit comprises a capacitor connected in series with a triac across the lamp, and a branch including a first resistor connected in series with a zener diode and a second resistor between the junction of the capacitor and triac and one side of the AC source. A driving circuit for the triac includes a diac connected to the junction of the second resistor and zener diode.

Abstract: A parallel circuit of a capacitor and a switching element is connected to a hot cathode discharge lamp lighting device using a high frequency and high voltage generating means for permitting the flow of current into the filaments of the hot cathode type discharge lamp only at the lamp starting time. The switching element of the parallel circuit is a current controlled resistance element, such as a switching semiconductor, having a break-over voltage V.sub.BO lower than the capacitor terminal voltage during the initial ignition period and higher than the capacitor terminal voltage during the reignition or operation period, whereby the filament current to the discharge lamp may be used for preheating of the filament in the initial ignition period. The filament current may be stopped or reduced by turning off of the switching element by raising the terminal voltage of the capacitor in the reignition period during normal operation.

Abstract: An electrical energy conservation control method and apparatus are provided which produce efficient control of the light output of either incandescent or fluorescent lamps or the outputs of other electrical load devices under circumstances where the rated output is not required. The control method and apparatus combines electronic (transistor) switching techniques with the use of reactive circuit components to provide control of the magnitude of current flowing through the load device during the AC input voltage sine wave and to permit some current flow at all times during each voltage half wave. The control technique is non-dissipative in the sense that losses are virtually limited to switching transitions and passive circuit element losses. The control is accomplished by controlling the time period that a transistor is saturated full-on.

Abstract: Energy-saving circuitry for a rapid-start fluorescent lighting system includes a reactance-modifying capacitor coupled in series with first and second fluorescent lamps and includes a filament switch which is operative to conduct filament heating current during starting of the first lamp. The filament switch is coupled between filaments at opposite ends of the first fluorescent lamp and triggers to a low impedance state in response to the lamp starting voltage. A capacitor bypass switch can be coupled in parallel with the reactance-modifying capacitor to reduce the impedance of the series circuit during lamp starting.

Abstract: There is disclosed herein an electronic flash system which obviates the need for the typical large capacity main capacitor as the power source for the flashtube. The system includes a conventional flashtube, trigger circuit for ionizing the flashtube and control circuit for turning on and off an electronic switching element which applies the main operating power to the flashtube. The ignition circuit for the flashtube uses a relatively small capacitor which is charged to a high voltage level for first igniting the flashtube and causing it to commence emission of light. Once ignited, a medium voltage power supply supplies the necessary current level for the required length of time to continue the production of the flash of light. The system also enables the use of a relatively small electronic switch as well as a relatively small voltage converter for charging the ignition capacitor.

Abstract: A process and apparatus for charging a capacitor, particularly for flash guns with a fast flash series, so as to achieve a short charging time while avoiding a high charging current pulse, the charging current during the course of the charging being regulated to a value which at least approaches a constant. The time constant of the charging circuit is altered during the charging process by a controlled resistance arrangement which is controlled in dependence upon the charging voltage of the capacitor.

Abstract: A spark source circuit has a discharge circuit including reactive means connected in circuit between a capacitor and an analytical spark gap and switching means for effectively removing the capacitor from the discharge circuit after an initial flow of current through the spark gap so that the current flow through the spark gap is essentially unidirectional. At the start of the capacitor discharge, the discharge circuit is essentially of the classical RLC oscillatory discharge type; and the switching action converts the discharge circuit to essentially a classical RL discharge type circuit for the remainder of the spark discharge. The circuit is simple and efficient, permits use of ceramic capacitors, and may be housed in a sealed enclosure.

Abstract: Discharge lamp energization circuit to operate a discharge lamp 1 over two electronic switches 10, 11, for example high-voltage, high-current switching transistors, which alternately apply a d-c voltage connected across two capacitors 4, 5, in opposite polarity, to the lamp circuit. The capacitors have the same value, and the lamp circuit includes a serially connected inductance. The electronic switching transistors are supplied from a frequency constant square-wave generator 16, at frequency high with respect to power line frequency, for example within the audio or supersonic range, e.g. 7.5 kHz. A separate ignition or starting circuit may be provided or the series inductance 2 and a capacitor 20 connected in parallel with the lamp may form a series resonance circuit tuned to a low odd harmonic (3, 5 7) of the lamp operating frequency.

Abstract: A dimming circuit for operating a fluorescent lamp in an incandescent-to-fluorescent adapter at two selectable current levels. The circuit includes a choke which is series connected between the center contact of a three-contact incandescent base and one of the lamp filament coils, and a capacitor connected between the ring contact and center contact of the base. A bleeder resistor of the PTC type is connected across the capacitor. For use with an incandescent lamp fixture having a four-position, three-way switch, the circuit further includes a current limiting discharge resistor connected in series with the capacitor.

Abstract: A glow plug driver adapted to be coupled to a power supply and a glow plug comprising first and second conductive leads for coupling the glow plug to the power supply and an electronic switch in the first lead having conductive and nonconductive states so that pulses of electrical energy can be supplied to the glow plug. A resistor and a capacitor are coupled between the leads in parallel with the glow plug so that the capacitor can charge when the electronic switch is in the conductive state and discharge when the electronic switch is in the nonconductive state. A timer is used to place the electronic switch in the conductive state for a predetermined amount of time. The timer is in turn controlled by a transistor having its base coupled to a junction between the resistor and the capacitor.

Abstract: High frequency circuit for operating gaseous discharge lamps includes oppositely poled controlled semiconductor switches connected to a resonant circuit comprising a capacitor and inductor connected to the lamp load and serving both as a high-frequency ballast for the lamp and to effect alternating turn-off of the semiconductor switches. Diodes are connected to the switches in a manner to provide energy pulses on the lamp load without return to the supply source. A control circuit is provided for alternately triggering the semiconductor switches into operation.

Abstract: A control circuit for a power switch like a triac to be connected in series with a load device, at a situs where only one AC power conductor and a conductor extending to the load device is available, is energized from a DC power supply energized from these conductors. The power supply includes at least one rectifier connected in series with a capacitor, the terminals of which capacitor constitute the DC output terminal of the DC power supply, an impedance of much greater resistance than that of the load device and through which the capacitor is charged when the triac is in its non-conductive mode, and a normally non-conductive triggerable low impedance threshold device shunting the high impedance and triggered momentarily into conduction as the applied AC voltage goes through zero when the triac is to be in its conductive mode. Current flow through this threshold device triggers the power switch into conduction a short interval after passage of this voltage through zero.

Abstract: A silicon controlled rectifier (SCR) lamp supply trigger circuit, responsive to control circuitry, produces trigger currents for the SCR which transmits the required voltage to illumination lamps in a document image capturing system. The trigger circuit includes a single AC input supply voltage having a positive and negative portion and electronic components for accumulating the respective voltage portions and isolating them to avoid unwanted signal interference with the control circuitry regulating the lamp supply voltage. Devices discharge the voltage accumulating components in response to the control circuitry of the SCR lamp supply and feed the discharged voltage to an apparatus for conversion to a current for triggering the SCR. Residual voltages remaining on the voltage accumulating components are automatically discharged during that portion of the AC input supply voltage which is opposite to the polarity of the charges stored on the voltage accumulating components.

Abstract: Add-on device for connection in series with one lamp of a two-lamp rapid-start fluorescent light system to reduce by a predetermined amount the nominal power consumption and light output of the system. The device has normally closed relay contacts which are in circuit with one of the electrodes of one of the lamps and a power-reducing capacitor is in shunt with one of the relay contacts. Upon turning on the system, a solid-state time-delay and relay-coil-energizing circuit is actuated which opens the relay contacts only after the lamps have been started and are operating with nominal power consumption. This places the shunt capacitor in series with the operating lamps and reduces the nominal power consumption by a predetermined amount.

Abstract: The life expectancy of the energy storing capacitors in a flash lamp drive circuit is extended by charging them in response to a trigger signal which also initiates the ionization pulse to the lamp after a delay time so that a desired threshold of energy stored in the capacitors is directed to the lamp.

Abstract: A circuit for starting and operating an arc lamp includes a full wave rectifier having an input connected to a source of alternating current line voltage and a pair of output terminals having a filter capacitor connected thereacross for providing a source of direct current voltage. Connected to one of the direct current terminals is a resonant charging circuit comprising a controlled rectifier switch, an inductor and a capacitor serially connected in a circuit loop. Another inductor, which may comprise the secondary winding of a starting pulse transformer, is connected between the output of the resonant circuit and one of the supply terminals for the arc lamp to provide the dual function of both averaging filter and lamp ballast. The reference terminal of the direct current source is connected to the other arc lamp supply terminal and through a back swing diode to the output of the resonant circuit.

Abstract: An electric discharge lamp circuit arrangement wherein rapid starting of the lamp is obtained by charging a ballast impedance capacitance via a unidirectional current conducting path in a sense such as to breakdown a voltage breakdown device in the control electrode lead of a controllable switching device connected with the lamp to provide a current path between the supply terminals comprising, in series, the capacitance, heating means for the lamp main electrodes and the switching device. On breakdown, the switching device temporarily conducts to complete the series path and cause a pulse of current to flow through the heating means, whereafter the capacitor recharges and a further current pulse is produced. The unidirectional current path may extend through the breakdown device or by-pass the breakdown device via a rectifier.

Abstract: A circuit for operating an electric discharge lamp from an a.c. supply wherein a burst of high voltage pulses for starting the lamp is generated during each cycle or half cycle of the supply by rapidly turning on and off an electronic switch, e.g. a triac, connected between a tapping point on a ballast inductance and an input terminal of the circuit.

Abstract: A power circuit for a discharge lamp, in particular a flash lamp serving as light source in an optical analysis apparatus which comprises an electric power source outputting a d.c. voltage and capable of reabsorbing electrical energy, which also comprises an energy transferring circuit inserted between the electric power source and a first capacitor connected to the lamp, the capacitor being charged via the energy transferring circuit and adapted to store the energy required for each discharge across the lamp, the energy transferring circuit comprising a first current path comprising the primary winding of an autotransformer and adapted to transfer current from the electric power source to the first capacitor until the voltage across it reaches a predetermined value, and a second current path comprising a second capacitor for storing part of the surplus or non-used energy stored in the autotransformer during the charging of the first capacitor.

Abstract: The invention relates to a sun lamp provided with a timer circuit that includes a capacitor. As soon as the capacitor reaches a certain charge condition the sun lamp is switched-off.The sun lamp also comprises a safety circuit responsive to a given level of current through the capacitor, which indicates a defect in the timer circuit 2, to rapidly terminate the irradiation.

Abstract: The invention relates to a starter for igniting a low-pressure sodium lamp. The starter is provided with an oscillator circuit consisting of an electric coil, a first capacitor and a controlled semiconductor switching element.In accordance with the invention the starter also comprises a parallel circuit of a resistor having a positive temperature coefficient and a second capacitor, this parallel circuit and the oscillator circuit being in series. This series circuit is connected between two electrodes of the lamp. In the case where a defective lamp must be replaced by a new lamp--the supply voltage being switched on--in spite of the hot state of the resistor with positive temperature coefficient a plurality of starting pulses will nevertheless be passed through the second capacitor to the new lamp whereafter this lamp can ignite.

Abstract: A power reducer for a rapid start fluorescent lamp includes a time delay circuit that discontinues heater current to the lamp cathode after a predetermined time interval and places, at the same time, a current-reducing capacitor in series with the lamp.

Abstract: Direct current ballasting and starting circuitry for efficiently operating a gaseous discharge lamp on direct current. A series-pass switching transistor in one of a pair of input lines alternately switches between on and off states to periodically supply pulses of energy from a source of direct current voltage. During steady-state operation, current sensing circuitry limits the maximum current conductable by the transistor such that the output of the circuitry is current regulated. A filter, in series with the transistor, smoothes the pulses of energy delivered by the transistor into direct current with a comparatively small alternating current component. Starting circuitry in series connection between the filter and an output terminal, senses the nonionized state of the lamp and provides a voltage pulse of sufficient magnitude and duration to initiate ionization in the lamp, but permits uninterfered passage of current through the filter to the output.

Abstract: The sources of ultraviolet light processors containing a plurality of such sources are started sequentially to reduce the current surge at start-up.

Abstract: There is provided in combination with a rapid-start series-sequence type ballast for two low-pressure mercury discharge lamps, apparatus for reducing the power consumption of both lamps. The apparatus utilizes switch means in conjunction with a capacitor to limit the current supply to the lamps after the lamps are energized. The switch means has two members in series circuit arrangement with one of the electrodes of one of the lamps. Each member is connected on opposite sides of the electrode. The capacitor is connected in parallel circuit arrangement with one of the members. Initially upon energization the switch means has a low impedance state to permit current flow and then switches to a high impedance state. The switch means permits preheating of the electrode and thereafter upon response to current flow switches and causes the lamp current to pass through the capacitor and thereby decrease by a predetermined amount the current through the normally operating lamps.

Abstract: A circuit arrangement for igniting at least one gas discharge flash tube having two main electrodes includes a chargeable flash capacitor connected in parallel with the flash tube and an electronic switch. These elements are connected to a voltage generator which supplies ignition voltage pulses and the electronic switch constitutes a gas discharge path for the flash tube. The voltage generator has such a low impedance, in particular a low inductance, that the ignition voltage pulses supplied thereby at least approximately adiabatically heat the gas discharge paths.

Abstract: There is provided in combination with a rapid-start series-sequence type ballast for two low-pressure mercury discharge lamps, apparatus for reducing the power consumption of both lamps. The apparatus utilizes switch means in conjunction with a capacitor to limit the current supply to the lamps after the lamps are energized. The switch means has two members in series circuit arrangement with one of the electrodes of one of the lamps. Each member is connected on opposite sides of the electrode. The capacitor is connected in parallel circuit arrangement with one of the members. Initially upon energization the switch means has a low impedance state to permit current flow and then switches to a high impedance state. The switch means permits preheating of the electrode and thereafter upon response to current flow switches and causes the lamp current to pass through the capacitor and thereby decrease by a predetermined amount the current through the normally operating lamps.