Abstract: A lamp assembly configured to inductively receive power from a primary coil. The lamp assembly includes a lamp circuit including a secondary and a lamp connected in series. In a first aspect, the lamp circuit includes a capacitor connected in series with the lamp and the secondary to tune the circuit to resonance. The capacitor is preferably selected to have a reactance that is substantially equal to or slightly less than the reactance of the secondary and the impedance of the lamp. In a second aspect, the lamp assembly includes a sealed transparent sleeve that entirely encloses the lamp circuit so that the transparent sleeve is fully closed and unpenetrated. The transparent sleeve is preferably the lamp sleeve itself, with the secondary, capacitor and any desired starter mechanism disposed within its interior.

Abstract: A reliable and efficient circuit for lighting a discharge lamp is described. An inverter accepts a direct current supply voltage and outputs an alternating current lamp voltage to drive the discharge lamp at a relatively high frequency. In one embodiment, the inverter includes semiconductor switches in a full-bridge configuration, a transformer feedback circuit to control the semiconductor switches, and a series L-C resonant circuit. In one embodiment, the inverter includes semiconductor switches in a half-bridge configuration, a transformer feedback circuit to control the semiconductor switches, and a series L-C resonant circuit. The inverter can drive multiple discharge lamps in a parallel configuration. A bypass circuit can also be coupled across a cathode of the discharge lamp to extend the life of the discharge lamp. The bypass circuit activates when a lamp cathode wears out.

Abstract: A reliable strobe power supply is disclosed that provides requisite light energy for emergency uses without causing EMI problems. A two phase dual flyback power converter operating in transitional mode is disclosed containing a microcontroller that maintains a 180 degree displacement between the two phases by enabling a small, variable dead time between the cessation of stored energy in the flyback transformers and turn-on of the associated power switching transistor for one or the other phases. The power supply is capable of detecting a fault (neoning) and automatically correcting the condition by incrementing the flash capacitor charge off-time delay. The power supply is also capable of tolerating defective (persistently neoning) strobe tubes that cause an inordinate delay in capacitor charging by turning them off.

Abstract: A multi-lamp backlight system. The system comprises a core, a first coil set wrapped around the core, to which a first AC voltage is applied, a second and third coil sets wrapped around the core and respectively disposed on two sides of the first coil set, on which a second and third AC voltage are induced by the first voltage signal applied to the first coil set respectively, wherein the numbers of coils of the second and third coil sets are substantially the same, and first and second lamps are supplied with power by the second and third AC voltages respectively.

Abstract: To efficiently and cost-effectively produce a light source, a CCFL circuit can include a PMOS transistor, first and second NMOS transistors, and a high turns ratio transformer. The transformer can include a primary coil having a center tap, thereby forming first and second primary windings, as well as a secondary coil. The PMOS transistor can be connected to the center tap for driving the transformer. The first and second NMOS transistors can be connected to the first and second primary windings, respectively. Of importance, the first primary winding is tightly coupled to the second primary winding, whereas the first and second primary windings are loosely coupled to the secondary coil.

Abstract: A description is given of a gas-discharge lamp base (11) with a housing comprising an upper part (10) and a cover (40), a support (16) accommodated in the housing for receiving the components, with a transformer, with inductances connected in series with the lamp (1) and a capacitance connected in parallel with the lamp (1), the transformer comprising a bar transformer (23). This construction permits particularly efficient production, because the support can be constructed as a simple leadframe which permits automatic component fitting.

Abstract: A multi-lamp system for driving a lamp set having a first lamp and a second lamp comprises a driving circuit for converting a DC signal to an AC signal, a transformer having a primary side coupled to the driving circuit and a secondary side for outputting the AC power, and a current balance circuit coupled to the low voltage terminal of the lamp set for balancing the current values flowing through the first lamp and the second lamp. The current balance circuit comprises a magnetic core, a first winding coupled to the first lamp and a second winding coupled to the second lamp. The first winding and the second winding are wound on the magnetic core and have the same coil number.

Abstract: The invention relates to a ballast for operating at least one low-pressure discharge lamp, preferably a three- or four-lamp ballast. In order for all parallel- or series-connected low-pressure discharge lamps (L40-L43) to shine equally bright even in the case of strong dimming, the ballast according to the invention has a transformer (Tr40) for balancing the currents in the lamp branch circuits and a transformer (Tr41) for compensating the losses owing to parasitic capacitances.

Abstract: A fluorescent lamp driver circuit has regulator (SR); primary circuit of transformer (TF); electronic switches (TR2A and TR2B) and current sensing device (Rsense) connected successively in series across power supply (PSF). Controller (CTRL) is connected to create a feed back loop. The secondary circuit of transformer (TF) is coupled to fluorescent lamps (U10 and U11) via ballast capacitors (C1 and C2). Diode (D1) creates unidirectional current flow, so current sensing device (Rsense) indicates only energy input to lamps (U10 and U11). Capacitors (C1 and C2) are placed physically very close to their respective lamps, enabling good matching of currents through lamps (U10 and U11). Pulse width modulator (PM) with predetermined input is connected to regulator (SR) and, via delay circuit (TD) to controller (CTRL), thus permitting a larger dimming ratio, and further control of input power.

Abstract: A rare gas discharge lamp lighting apparatus has a power supply, a transformer, a switching element which is in series connected to the power supply and a primary side of the transformer, a rare gas discharge lamp connected on a secondary side of the transformer, and an input terminal for inputting a lamp lighting signal, a controlling circuit for outputting a controlling signal to the switching circuit by calculating at least one of output voltage, output current and output power, and an operating voltage input terminal to which voltage is impressed to initiate an operation of the controlling circuit based on the lamp lighting signal, wherein a delay element is provided between the input terminal and the operating voltage input terminal.

Abstract: A discharge lamp lighting device comprises a plurality of discharge lamps, at least one reflector, and at least one leakage transformer. Each leakage transformer lights three discharge lamps and comprises: a first leakage transformer, which comprises a frame-core shaped substantially rectangular and two bar-cores disposed parallel to each other and orthogonal to two opposing sides of the frame-core with a predetermined gap from the frame-core, has two of primary and secondary windings structurally independent of each other, and which lights two discharge lamps of the three; and a second leakage transformer, which comprises a frame-core shaped substantially like square-U letter and a bar-core disposed orthogonal to two opposing sides of the frame-core with a predetermined gap from the frame-core, has one primary and secondary winding structurally independent of each other, and which lights remaining one discharge lamp.

Abstract: A ballast for electrical lighting fixtures with improved thermal protection features is disclosed. The ballast has ballast laminations, primary and secondary coils, and a thermal protector, the thermal protector being wired in series with the secondary coil. The ballast preferably is of the type having multiple input voltage taps on the primary coil; in such cases, the electrical positioning of the thermal protector in series with the secondary coil causes the wiring assembly of the thermal protector (as part of the ballast) to be independent of the primary coil input voltage tap used in a particular application. Also disclosed are improved electrical lighting circuits for high-intensity-discharge lamps, the circuits having the above-described thermally-protected ballasts.

Abstract: A lighting control system provides variable arc current to one or more fluorescent gas discharge lamps and provides a heating voltage to the lamp electrodes. The system includes a start-up circuit which includes circuitry for providing a starting voltage to an output power conditioning circuit. The latter drives a switching unit to control the application of DC power to the fluorescent gas discharge lamps and to provide an operating voltage to an input power factor correction circuit. The input power factor correction circuit boosts the converted DC power and the operating voltage. The start-up circuit includes a plurality of voltage doubling rectifier circuits and a plurality of zener diodes which receive the operating voltage and are electrically connected to the input power factor correction circuit and the output power conditioning unit so as to provide a regulated bias voltage supply to the output power conditioning unit and to the input power factor correction circuit.

Abstract: Free-running half-bridge inverter (HP) for operating gas discharge lamps having a current transformer as a feedback device. The half-bridge transistors (T1, T2) are essentially voltage controlled transistors (MOSFET). The drive circuits (1, 2) for the half-bridge transistors (T1, T2) contain a voltage threshold value switch (D2, R2) which, on reaching its voltage threshold, essentially carries a current which is proportional to the load current of the half-bridge inverter (HB).

Abstract: An apparatus controlling a cold cathode fluorescent lamp and a scanning apparatus having the same are disclosed.

Abstract: A power supply apparatus of a lighting system using microwave includes: a high voltage transformer for transforming a general AC power to an AC power of high voltage and outputting the high voltage AC power; and a voltage doubler unit for transforming the high voltage AC power into a high voltage DC power, increasing the frequency of the current of the DC power, and outputting the DC power having the increased frequency. Since the frequency of the power applied to the magnetron is increased to remove the flicker phenomenon, a stable light can be radiated to an external space.

Abstract: An inverter for driving multiple discharge lamps. The inverter has a transformer for driving a first discharge lamp and a second discharge lamp. The inverter also includes a first balancing circuit connected in series with the first discharge lamp and a second balancing circuit connected in series with the second discharge lamp. According to a matching signal, the first and the second balancing circuits adjust a first lamp current through the first discharge lamp and a second lamp current through the second discharge lamp, respectively. A comparator is provided to receive a first sensing signal from the first balancing circuit and a second sensing signal from the second balancing circuit. Comparing the first sensing signal with the second sensing signal, the comparator generates the matching signal which controls the first and the second balancing circuits to equalize the first lamp current and the second lamp current.

Abstract: In a circuit arrangement for operating at least two discharge lamps and comprising an equalizer transformer, removal or extinguishing of one of the lamps is detected by monitoring the voltage over the equalizer transformer and switching off the circuit arrangement in case the voltage over the equalizer transformer is higher than a reference voltage.

Abstract: A ballast circuit includes an output isolation transformer having a primary winding and first and second secondary terminals coupled to opposing ballast lamp terminals for additively applying potentials on the primary winding and the first and second secondary winding potentials across the lamp and limiting ground fault voltages. The circuit can include a closed loop feedback path from a load to a feedback rectifier for promoting linear operation of an input rectifier.

Abstract: A DC/AC converter circuit structure for driving a plurality of cold cathode fluorescent lamps is described. A common-mode choke is used between the cold cathode fluorescent lamps. The common-mode choke balances the currents respectively flowing through the cold cathode fluorescent lamps.

Abstract: An ignition system for an engine includes an exciter circuit for use with an igniter, the exciter circuit having a step-up transformer the utilizes a relatively low voltage in its primary to produce a high voltage pulse that is applied to the igniter to create ionization and breakdown. The system also utilizes a low voltage high energy circuit to provide high current energy to the igniter after initial breakdown and during the plasma arc phase. The high energy circuit is decoupled from the step-up transformer so that high current is conducted through a bypass diode rather than through the transformer.

Abstract: An AC power generating apparatus for lighting a discharge lamp has a smoothing circuit with an electrolytic capacitor therein for smoothing ripples included in a DC voltage supplied from a power source. The apparatus further has a switching device and a transformer for transforming a smoothed voltage by turning on and off application of the smoothed voltage to the transformer thereby to supply AC electric power for activating a discharge lamp. A capacitor is connected in parallel with the electrolytic capacitor. This parallel capacitor is located inside an area surrounded by the transformer, the switching device and the electrolytic capacitor to reduce a circuit area where electromagnetic radiation noise is generated.

Abstract: The present invention discloses a safety output device of electronic ballast, which includes isolating transformer, relay, control circuit and induction circuit controlling relay. Two output terminals of electronic ballast connect to the safety output device. The alternation between the functions of relay is controlled by means of induction circuit to trigger control circuit; when the lamp is not plugged into the load circuit, low voltage below safe voltage of human body will be applied to both output terminals of the safety output device, and when the lamp is plugged into the load circuit, voltage applied to both output terminals of the safety output device will change to the high frequency high voltage output by electronic ballast, thus making the loaded circuit in normal operation. The electronic ballast in accordance with the present invention may ensure, under any circumstances, the safety voltage is output from both output terminals of electronic ballast while the load of lamp is not present.

Abstract: In one example of a transformer, which is used in a dc-to-ac inverter circuit for lighting an electrical discharge lamp, a construction may be employed in which a primary winding and a secondary winding are gripped on both sides by a pair of cores composed of a magnetic material. In this transformer, a spacer is employed when forming a gap between the two cores. As a result, not only does the height dimension of the transformer grow large, but there is also a risk of the magnetic flux leaking from the spacer part to the outside.

Abstract: Control is carried out in such a manner that a transformer 10 constituting a DC voltage converting circuit 15 stores energy while a switching element 11 provided on the primary side of the transformer 10 is set in an ON state, and the transformer 10 outputs the energy while the element 11 is turned ON when the energy is completely output from a secondary winding 10s. For this purpose, a duration from a time that a secondary current I2 of the transformer 10 reaches zero to a time that a primary current Ip of the transformer 10 is started to flow is detected, and a switching frequency is changed by control means 16 in order to shorten the duration.

Abstract: An integrated filter with both common-mode and differential-mode functions is disclosed. The integrated filter comprises a magnetic core, two windings and a frame for installing the windings. The magnetic core further comprises a rectangular core and an I-shaped core. The frame is fixed to a column of the rectangular core. These two windings are wound on the frame. The I-core is placed across an interior opening of the rectangular core and between these two windings. One integrated filter with a magnetic core composed of a &thgr;-shaped core and an I-shaped core is also disclosed. In addition, the magnetic core may comprise a &thgr;-shaped core and an E-shaped core. The E-core is placed across an interior opening of the &thgr;-shaped core or upright on the &thgr;-shaped core and between these two windings. One integrated filter with a magnetic core composed of a rectangular core and an E-shaped core is also disclosed.

Abstract: A lamp assembly configured to inductively receive power from a primary coil. The lamp assembly includes a lamp circuit including a secondary and a lamp connected in series. In a first aspect, the lamp circuit includes a capacitor connected in series with the lamp and the secondary to tune the circuit to resonance. The capacitor is preferably selected to have a reactance that is substantially equal to or slightly less than the reactance of the secondary and the impedance of the lamp. In a second aspect, the lamp assembly includes a sealed transparent sleeve that entirely encloses the lamp circuit so that the transparent sleeve is fully closed and unpenetrated. The transparent sleeve is preferably the lamp sleeve itself, with the secondary, capacitor and any desired starter mechanism disposed within its interior.

Abstract: The described DC to AC inverter efficiently controls the amount of electrical power used to drive a cold cathode fluorescent lamp (CCFL). The output is a fairly pure sine wave which is proportional to an input control voltage. The output waveform purity is ensured by driving a symmetrical rectangular waveform into a second-order, low pass filter at the resonant frequency of the filter for all conditions of line voltage and delivered power. Operating stress on the step-up transformer is minimized by placing the load (lamp) directly across the secondary side of the transformer. When configured to regulate delivered power, the secondary side may be fully floated which practically eliminates a thermometer effect on the operation of the lamp. All of the active elements, including the power switches, may be integrated into a monolithic silicon circuit.

Abstract: The present invention relates to a vacuum arc discharge power supply. The power supply may be a high frequency resonant AC supply or it may be rectified to give resonant DC. The power supply of the present invention may be used in x-ray production, vacuum arc deposition equipment, vacuum metal refining, ion implantation devices, or other applications that perform vacuum arc discharge.

Abstract: A lighting circuit of confirming the insulation property of an HID lamp and a lighting circuit upon starting the operation of the HID lamp to previously prevent damages of the main circuit, and starting discharge at the lowest starting voltage in accordance with the characteristics of the HID lamp, comprising a control section (C) having an insulation property confirming means for confirming that the current does not flow in a state of applying a predetermined voltage to the main circuit (2) before applying the starting voltage to an HID lamp (1) and a starting voltage variable control means for increasing the secondary voltage generated from the step-up transformer (10) of the starting circuit (3) stepwise after confirming the insulation property.

Abstract: A resonant driving system for a fluorescent lamp having one end connected to a primary winding of a transformer. The driving system includes an inductor inserted between an input section of the resonant driving system and an internal circuit node that is connected to another end of the fluorescent lamp a converter inserted between the internal node and a voltage reference and comprising a first transistor and a second transistor of the complementary type, inserted, in series to each other, between the internal node and the voltage reference, and a control circuit connected to a secondary winding of the transformer and to the converter as well as to the control terminals of the first and second transistors of the converter, wherein the control circuit comprises an inductor connected to a resistor that is connected to the control terminals of the first and second transistors through a first and a second capacitor respectively.

Abstract: The discharge lamp lighting device according to the present invention is provided with a high-voltage generating transformer which comprises a core, a secondary winding part disposed in a plurality of sections on the outside of the core, and a primary winding part disposed on the outside of the secondary winding part and in which a high-voltage side terminal of said secondary winding part is connected to a terminal of the core and a low-voltage side terminal of the secondary winding part is connected to a terminal of the primary winding part.

Abstract: A compact single-stage electronic ballast circuit for emergency lighting applications, integrating the functions of a flyback charger, a flyback discharger and a half-bridge series resonant parallel loaded electronic ballast into a single-stage electronic ballast. The present invention only employs two active switches so as to achieve an electronic ballast for emergency lighting applications when the electricity is out. Furthermore, the present invention reduces the fabrication cost by simplifying the circuit configuration and reducing the number of employed active switching elements.

Abstract: A discharge lamp lighting device for AC lighting has PT(21), CT1(22), a fluctuation detection circuit (28), and a control circuit (36). PT(21) detects a voltage to be supplied to a HID bulb (5) and CT1(22) detects a current to be supplied to the HID bulb (5). The fluctuation detection circuit (28) generates an output power equivalent value obtained by adding each voltage value corresponding to each detected value by PT(21) and CT1(22), and outputs the fluctuation signal corresponding to the change of the output power equivalent value. The control circuit (36) changes a duty ratio of a control signal to be supplied to the switching transistor (6) according to the fluctuation signal.

Abstract: Circuit arrangement for igniting high-pressure discharge lamps by means of resonance ignition by a resonant circuit. According to the invention, the voltage for an auxiliary ignition electrode is provided by an ignition transformer into which the voltage is fed via an inductor of the resonant circuit. The inductor of the resonant circuit preferably forms the primary winding of the ignition transformer.

Abstract: A gas-discharge lamp lighting apparatus includes: a power conditioning unit regulating power supplied from a power source, and outputting voltages with mutually different levels from two output terminals; a switching circuit unit coupled between the output terminals of the power conditioning unit and including at least one switching element; and a pulse transformer generating a high-voltage pulse, placed in a circuit connecting the output terminals of the switching circuit unit and a gas-discharge lamp. A first terminal of a primary winding of the pulse transformer is connected to a first output terminal of the power conditioning unit via a first output terminal of the switching circuit unit, and a second terminal of the primary winding is directly connected to a second output terminal of the power conditioning unit.

Abstract: In a discharge-lamp lighting circuit for turning on a plurality of discharge lamps, starting circuits 8 for supplying starting pulses to the respective discharge lamps are provided. Each starting circuit 8 has transformers T1 and T2 equal in number to the discharge lamps and each of the transformers has a primary and a secondary winding. The discharge lamps 6—1 and 6—2 are connected to the respective secondary windings T1s and T2s. Capacitors C1 and C2 are connected to the respective primary windings T1p and T2p of the transformers and one switch element SW is provided in a circuit including the primary windings and the capacitors. When the accumulated charge in each capacitor is discharged via the primary winding of the transformer as the switch element SW conducts, the starting pulse is generated and supplied to each discharge lamp via the secondary winding of each transformer.

Abstract: A power supply apparatus of a fighting system using microwave includes: a high voltage transformer for transforming a general AC power to an AC power of high voltage and outputting the high voltage AC power; and a voltage doubler unit for transforming the high voltage AC power into a high voltage DC power, increasing the frequency of the current of the DC power, and outputting the DC power having the increased frequency. Since the frequency of the power applied to the magnetron is increased to remove the flicker phenomenon, a stable light can be radiated to an external space.

Abstract: A ballast circuit includes an output isolation transformer having a primary winding and first and second secondary terminals coupled to opposing ballast lamp terminals for additively applying potentials on the primary winding and the first and second secondary winding potentials across the lamp and limiting ground fault voltages. The circuit can include a closed loop feedback path from a load to a feedback rectifier for promoting linear operation of an input rectifier.

Abstract: A ballast circuit with an ignitor circuit for starting serially connected HID lamps is provided. The ballast circuit comprises an electromagnetic ballast arrangement for driving the lamps and an ignitor circuit for starting the lamps. In an embodiment of the invention, the ignitor circuit comprises a voltage-breakover device, a first capacitor, a resistor, a pulse autotransformer, and a second capacitor. A pulse autotransformer is associated with each subsequent lamp after a first lamp of the serially connected lamps.

Abstract: The invention relates to a rod-core transformer for use as a starting transformer in the cap of a high-pressure discharge lamp for a motor vehicle headlight. According to the invention, the rod-core transformer has at least two cores (2, 3) which are in the form of rods and are arranged alongside one another, and on each of which a multilayer secondary winding (4, 5) is wound, with the respective layers (4a, 4b, 4c, 4d) and (5a, 5b, 5c, 5d) being connected in parallel and being arranged one above the other without any offset. Furthermore the secondary windings (4, 5) are electrically conductively connected to one another, with their total resistance being at most 2 &OHgr;. The transformer according to the invention is particularly highly suitable for use as a starting transformer for high-pressure discharge lamps with a low operating voltage, for example halogen metal-vapour high-pressure discharge lamps which do not contain mercury.

Abstract: A current equalizer assembly for LCD backlight panel comprises at least a differential current choke and at least a capacitor. The capacitor is arranged striding on a terminal (B) at a primary coil and on a terminal (D) at a secondary coil of the differential current choke so as to equalize the current flowing through every cold cathode fluorescent lamp (CCFL) connected to the differential current choke and the lightness thereof accordingly. Moreover, the capacitance of the stridden capacitor is replaceable by the intrinsic stray capacitance when the inductance of the differential current choke is properly selected.

Abstract: A power controller for the regulation of power consumption by gas pressurized vapor lamps can include a series of stages that steps down power being applied to the lamp without a significant loss of luminescence. Once the gas vapor has been heated to achieve luminescence, the power can be decreased based on several criteria including time, luminescence, and gas temperature. By removing the excess power being applied to the lamp, the same luminescence can be maintained using significantly less energy.

Abstract: A filament cut-back circuit is disclosed. The filament cut-back circuit comprises an impedance circuit coupled in series between either an AC voltage source and a primary filament winding, or a secondary filament winding and a filament. In response to an alternating voltage from the AC voltage source when coupled in series thereto or an alternating voltage from the secondary filament winding when coupled in series thereto, the impedance circuit operates as a short circuit when the alternating voltage is at a preheat frequency and operates as an open circuit when the alternating voltage is at an operating frequency.

Abstract: The invention relates to an operating method and an operating device for at least one electric lamp (11), which device has a control input (13, 14) for prescribing a setpoint for the brightness control of the lamp (11), and a transformer (15) for transmitting the voltage impressed on the control input (13, 14) to an evaluation device (16) which serves to evaluate the voltage impressed on the control input (13, 14).

Abstract: A discharge lamp driving device capable of detecting a lamp life end reliably in a high or low temperature environment for circuit protection, yet preventing the occurrence of the cataphoresis phenomenon. Impedance elements Z1 and Z1 are inserted respectively between one filament ends of individual discharge lamps La1 and La2 and a node (the ground) having no high frequency amplitude in order to detect a difference between AC components of individual lamp voltages VLa1 and VLa2 in closed loops of the discharge lamps La1 and La2 and the impedance elements Z1 and Z1 in order to judge whether or not the depletion of the emitter occurs. Thus, it is possible to reliably judge the presence of abnormality even when the amplitudes of the lamp voltages VLa1 and VLa2 varies in a range of low to high temperature.

Abstract: A neon light control device has a control box and at least one voltage transformer, wherein the control box has multiple outlet ports and the voltage transformer has an inlet port and an outlet port. The voltage transformer is detachably connected to the control box by a wire between one of the outlet ports and one of the inlet ports. When either the control box or the voltage transformer has a breakdown, only the damaged element needs to be repaired or replaced. Thus the replacement of the entire control device is not necessary.

Abstract: A referential rectangular wave is generated in a referential rectangular wave generating circuit 21, a level of the referential rectangular wave is integrated in an integrating circuit 22 to produce a chopping wave. In a comparing circuit 23, a voltage level of the chopping wave produced in the integrating circuit 22 is compared with a level of a feed-back voltage, and a control signal is output to a transistor 9. Also, in a delaying circuit 24, the control signal produced in the comparing circuit 23 is delayed by a delaying time corresponding to 180 degrees in a phase of the control signal without changing a duty ratio in an on-off control of a transistor 10, and the control signal is output to the transistor 10.

Abstract: A metal halide magnetic/electronic ballast with a compensation function for adjustment in autotransformer output voltage, which applies the compensation in various steps of voltage, to maintain the power constant. The metal halide ballast provides constant monitoring of the autotransformer input voltage, enabling the level to be stepped by triac switching. The triac switching is controlled by a switching control provided by a microcontroller. Less components are required, making the present invention simpler, less expensive to manufacture and more reliable.

Abstract: The invention improves an operating method, already described in the prior application 198 39 329.6, for a silent discharge lamp L, in which, using the forward transformer principle, a voltage pulse effecting a forward ignition is impressed from a primary circuit P via a transformer T into a secondary circuit S containing the silent discharge lamp L, and the secondary circuit S thereafter executes a half wave which, as a consequence of the polarization, leads to a back ignition in the discharge lamp L. The improvement consists essentially in that an inductance of the transformer T which governs a transformer current is temporally varied.