Abstract: An improved electronic ballast for a florescent lamp includes rectifying/filtering circuity coupled to an A.C. power source, high frequency switching circuitry, starting circuitry connected to the output terminal of the high frequency switching circuitry, and both starting current restraint circuitry connected to the output terminal of the rectifying/filtering circuitry and protection circuitry coupled to the starting circuitry. The starting current restraint circuitry includes a thermistor with a negative temperature coefficient which causes current flows through the filaments of the lamp to gradually increase during activation of the lamp tube so as to modify the heating of the filaments, lengthening the opertional life of the lamp.

Abstract: A compact fluorescent lamp in combination with a high frequency DC-AC converter includes a rectifier circuit and a buffer capacitor coupled between a source of low frequency AC voltage and the converter. A feedback capacitor couples a high frequency feedback signal corresponding to the converter output signal to the buffer capacitor via the rectifier circuit so as to improve the power factor of the combination.

Abstract: A ballast circuit system provides for efficient starting and operation of high voltage discharge lamps using a common 120 volt AC power source. As a result of this improved ballast circuit system, the necessary high voltage is generated from a normal 120 volt AC in such a way that there is low power loss. The system efficiency allows for use of plastic fixtures and small size packaging of the discharge lamp.

Abstract: A quick start ultraviolet emission unit with an elongated, electrode-type, mercury-filled, arc lamp having spaced end electrodes connected to an electrical power supply that connects to an alternating current power source and to each end electrode of the arc lamp for powering the lamp with an alternating current having a sinusoidal cycle, the unit includes a pulse generating, circuit means connected to said power supply for generating a high current, high voltage, electrical pulse added to the alternating current to the lamp during start-up and restart and a trigger circuit connected to the pulse generating circuit for triggering generated high current, high voltage electrical pulses at the peak potential in the sinusoidal cycle of the alternating current form the power supply.

Abstract: An electronic ballast circuit for two fluorescent lamps connected in parallel. A single switching inverter connected through a common coupling circuit provides high frequency alternating current for operation of both lamps independently of each other insuring operation of one lamp should the other cease operation. A dual toroidal transformer in the inverter insures both lamps receive current of the same frequency.

Abstract: A power supply for an electroluminescent lamp. The power supply includes an inverter circuit for conveying a DC voltage into a 2000 Hz sinusoidal voltage. The lamp is capacitive in its nature and changes its capacitive value over extended use which adjusts the output frequency of the inverter. A sensor and timers are included which in combination flash the lamp in a predetermined pattern when motion is detected by the sensor.

Abstract: The invention relates to an inverter powering a lamp that uses a switch to vary the resonance of the resonance circuit for starting and for operating.

Abstract: An improved fluorescent ballast circuit for 277 volt commercial application is disclosed utilizing a resonant circuit mechanism to generate high open circuit voltage (OCV) during lamp starting. The result is an energy efficient effective lighting system for commercial buildings.

Abstract: An improved arc discharge ballast is disclosed which comprises harmonic resonators, simple switching means and a drive circuit. The harmonic resonators, switching means and drive circuit are coupled to the lamp to provide squaring of the current waveform and provide even light output. By adding odd harmonic current elements to a lamp driven by a conventional ballast, advantages of even light output or power saving is obtained.

Abstract: A discharge lamp lighting apparatus comprises a transformer for stepping up an AC power source voltage from an AC power source to produce a high voltage as an output voltage required for lighting a discharge lamp. Particularly, the lighting apparatus further comprises a diode for rectifying the output voltage of the transformer to be supplied to the discharge lamp. The amount of current supply from the AC power source is determined to obtain an output impedance capable of limiting the current which is to flow through the discharge lamp after the start of discharging to maintain the voltage across the discharge lamp at a level required for continuing the discharge.

Abstract: An electronic ballast for correcting the power factor within a fluorescent lamp system. Use of an inductor in one of the AC power source leads and selected values of capacitance in a voltage divider and starting circuit combine to provide a power factor greater than 94%.

Abstract: A magnetic-type ballast powers an F40/T12 four foot fluorescent lamp from a regular 120 Volt/60 Hz power line by way of a main inductor. A power factor correction capacitor is connected in series with an auxiliary inductor of relatively small inductance value, thereby forming a series-combination; which series-combination is connected across the power line. A 30 Volt/60 Hz voltage is established across this auxiliary inductor. The phasing of this 30 Volt/60 Hz voltage is opposite that of the 120 Volt/60 Hz power line voltage. Thus, by adding the 30 Volt/.alpha.Hz voltage to the 120 Volt/60 Hz voltage, a 150 Volt/60 Hz voltage is obtained; which 150 Volt/60 Hz voltage is of magnitude adequate to properly power the F40/T12 four foot fluorescent lamp, although it is not of magnitude adequate to provide proper lamp ignition in a rapid-start mode.

Abstract: An adaptor circuit used to enable stable, flicker-free operation of T8-type fluorescent lamps in a lighting fixture which already has a standard two-lamp, series-sequence, 40 watt, rapid-start type ballast installed therein. The adaptor circuit contains an isolation transformer for controlling the voltage supplied by the ballast to the T8-type fluorescent lamps and a frequency selective impedance modifier circuit for controlling the operating current supplied by the ballast to the T8-type fluorescent lamps at preselected frequencies. In one embodiment, the frequency selective impedance modifier circuit substantially eliminates the third harmonic component of the fundamental frequency of the operating current.

Abstract: When a discharge lamp is started, high voltage pulses which superpose the voltage due to LC resonance of a resonance circuit are supplied to the discharge lamp, and breakdown occurs in the discharge lamp. The pulse energy needed for the high voltage pulses is small and the output power of the resonance circuit can be decreased. After the breakdown, the energy needed for the transfer from glow discharge to arc discharge is supplied by the resonance, and the high voltage pulses used to supply the starting energy are allowed to be stopped. Thus, the starting and restriking of a discharge lamp is sure, and the starting circuit for a discharge lamp can be made more compact.

Abstract: In a power-factor-corrected electronic ballast, an AC/DC converter comprises a half-bridge electronic self-oscillating inverter powered from non-filtered full-wave-rectified 120 Volt/60 HZ power line voltage, and its resulting amplitude-modulated 30 kHz output voltage is applied to a series-resonant L-C circuit. The 30 kHz voltage developing across the tank capacitor of this L-C circuit is rectified and applied as direct current to an energy-storing capacitor, from which a DC supply voltage is provided to a frequency-converting ballast which, in turn, provides a substantially non-modulated high-frequency AC output voltage used for powering a gas discharge lamp via a current-limiting inductor. Trigger pulses are provided to trigger the inverter into self-oscillation at the beginning of each pulse of DC voltage provided by the unfiltered rectified power line voltage. As soon as the magnitude of the DC voltage across the energy-storing capacitor exceeds a first level, the trigger pulses cease to be provided.

Abstract: An efficient, low operating temperature L-C ballast for a mini fluorescent lamp, wherein the ballast includes a capacitor connected in series with a transformer. The transformer comprises a primary coil and a shorted secondary coil. When used with a 4 watt mini fluorescent lamp, the primary coil should have 500 turns and the secondary should have 28 turns. Furthermore, the wiring used in the primary and secondary coils should be number 33 AWG wire. In an alternative embodiment, a resistor is loaded in parallel across the transformer. The resistor should preferably have a resistance ranging between 100 to 300 ohms.

Abstract: A dimmer with reduced filtering losses is connected into a conductor supplying power to a load from a mains power supply. It conventionally comprises a triac in series with a filter inductor between an input terminal and an output terminal and a circuit generating triggering signals for the triac. To reduce the losses in the inductor, which conventionally is in series with the load at all times but is active only during moments following triggering of the triac, to reduce the amplitude of the transient currents, a second triac triggered by a circuit with a time-delay greater than the time constant defined by the filter capacitor and inductor diverts the load current. An auxiliary low-value inductor attenuates transients due to triggering of the second triac.

Abstract: For coupling one, or more, gaseous discharge lamps to a high-frequency AC power-source a ballasting (current-limiting) network employs a first capacitor, a second inductor, and a transformer having a primary winding coupled to the high-frequency AC power-source by the first capacitor and a secondary winding coupled to the gaseous discharge lamp by the second inductor.

Abstract: A flashing light warning apparatus, which includes a voltage source (U), a main gate transformer (HW), a flash tube (R), an ignition device (Z), at least one storage condenser (K), and an electrical switching device (S), can be switched to provide light energy for daytime flashes and nighttime flashes in an uncomplicated, cost effective system which produces dependable light flashes. The night flashes have a light energy such that they can be seen from afar only with night vision apparatus. When the switching device turns off voltage production of the main gate transformer or further transmission of voltage from the at least one storage condenser, the ignition device is coupled to an auxiliary gate transformer (ZW) for carrying out light flash production by means of high frequency ignition voltage produced by the ignition device.

Abstract: A dimming system provides power from a switch-controlled power source in series with a leakage auto-transformer to a compact fluorescent lamp. The system incorporates a high-frequency resonant converter that provides high voltages to strike and maintain an electric discharge in the lamp. The converter is loaded in parallel by the lamp, whose impedance damps the converter to stabilize lamp operation. An inductor, connected between the leakage auto-transformer and the resonant converter, isolates the switch-controlled power source from the high-frequency voltage. The system can be used with a variety of standard leakage reactance auto-transformers to provide full-range dimming of compact fluorescent lamps from 5 to 100 percent light output with minimal flicker.

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 circuit (500) for driving two or more series-connected gas discharge lamps, having: an oscillator (518, 520, 522); and a transformer (524) with a primary winding (526) and a secondary winding (528). The transformer secondary winding has first (129A) and second (129B) points connected respectively to first (508) and second (514) output terminals across the series-connected lamps. A capacitor (532) couples the first point of the transformer secondary winding to an intermediate output terminal (112). The voltage produced by the secondary winding thus drives the lamps in series, while the pre-strike voltage produced across the secondary winding is applied across a single lamp (106) to cause it to strike. After striking, current to the intermediate output terminal (512) is limited by the capacitor (532). In this way, the voltage which needs to be produced across the secondary winding to ensure striking of all of the lamps is reduced.

Abstract: A direct current power supply which incorporates an alternating current circuit segment so as to enable the use of a reactive component as an impedance limiting circuit element. The alternating current is produced by pulse width modulation regulation of raw direct current and DC to AC inversion. A feedback circuit is provided to regulate the pulse width modulation in accordance with the direct current output by the power supply so as to obtain a desired output current.

Abstract: In one aspect of the present invention a capacitor is placed in series with the ballast and the lamp. The capacitor lowers the impedance during lamp starting and is shorted out when final arc conditions of the lamp are reached. Method and device for improvement of lumen maintenance of high intensity discharge lamps through minimizing the wall blackening during lamp starting is disclosed. Reducing the electrode material sputtering during the thermionic arc phase of the lamp starting process was achieved by decreasing the cathode fall voltage. The cathode fall voltage in these lamps was decreased by increasing the current flowing through during the starting phase. The increase of starting current was achieved by increasing the open circuit voltage or by decreasing ballast impedance.

Abstract: A controller operates in pre-ignition and ignition phases to obtain stable and reliable control of operation of a half-bridge DC-AC converter in a frequency range which is offset from a resonant frequency of an output circuit which includes a transformer and capacitors and which couples the converter to a fluorescent lamp load. The converter is supplied with a DC voltage from a switched-mode DC-DC supply of a pre-conditioner circuit which responds to a full-wave rectified AC voltage and which is supplied with pulse-width modulated gating pulses from the controller, preferably at a frequency which is the same as that of the converter. The controller monitors signals from the output circuit and pre-conditioner circuits and exercises control to reliable starting and highly efficient lamp operation and to obtain an in-phase proportional relationship of input voltage and current wave forms.

Abstract: For coupling one, or more, gaseous discharge lamps to a high-frequency AC power-source a ballasting (current-limiting) network employs a first capacitor, a second capacitor, and a transformer having a primary winding coupled to the high-frequency AC power-source by the first capacitor and a secondary winding coupled to the gaseous discharge lamp by the second capacitor.

Abstract: In electronic ballast having inverter rectifiers for fluorescent lamps, a regulation of the lamp current or of the lamp power is usually used in order to stabilize the lighting current independently of tolerances of the electrical properties of the fluorescent lamp or their aging phenomena. When such a regulation is simultaneously utilized for dimming the fluorescent lamp, difficulties arise at the lower limit of the dimming range at, for example, 1% of the nominal light power. The range of brightness at the lower limit is regulated on the basis of an additional regulation, dependent on the discharge resistance of the fluorescent lamp. An auxiliary measured quantity resulting therefrom is superimposed on the actuating quantity of the regulator that results from a reference/actual value comparison of the current or power regulation for the purpose of stabilizing the lamp current.

Abstract: In a circuit arrangement for the operation of high-pressure gas discharge lamps by means of a pulsatory supply current having a pulse recurrence frequency between 50 and 2000 Hz and a duty cycle between 0.2 and 0.8, a current having a high-frequency between 20 and 200 kHz is superimposed on the current pulses and with a modulation ratio beween 0.3 and 1. The high-frequency is an integral multiple of the pulse recurrence frequency. Thus, flickering of the lamps is avoided.

Abstract: A novel circuit for igniting and operating gas discharge lamps, in particular metal vapour lamps, comprises a buffer capacitor (C4) connected to a direct-current voltage (1,2) and connected in parallel with a circuit consisting of a choke and a capacitor connected in series (L1, C1). An electronic switch (S), for example a transistor and a recovery diode (D), is connected in parallel with the capacitor (C1). A second choke-capacitor series circuit (L2, C3) connected in series with the metal vapour lamp (L) is connected in parallel with the capacitor (C1), which is connected in parallel with the electronic switch (S). A second capacitor (C2) is directly connected in parallel with the the metal vapour lamp (L). The ignition circuit and the power supply circuit for the metal vapour lamp (L) are combined in this fluorescent lamp ballast, thus obviating the need for a separate ignition circuit. In addition, the circuit operates independently of the supply voltage.

Abstract: A lighting circuit for a fluorescent lamp includes a D.C. power supply which is connected across a pair of series transistors. A transformer has first and second windings connected to the bases of respective transistors and a third winding connected between the junction of the transistor pair and a booster transformer. The filaments of the fluorescent lamp are connected through a choke coil to the booster transformer, and a capacitor is connected in resonant circuit with the choke coil.

Abstract: An electronic capacitive ballast for fluorescent or other discharge lamps is provided which operates at a leading power factor, energy is conserved, lighting is instantaneous and the fluorescent lamps light up even if the filaments are broken. The fluorescent or other discharge lamps comprise of at least once capacitor having normal values upto 20 .mu.F. The capacitor is connected to a power source and at least one inductance coil having values upto 5 H. The inductance coil is connected to a starting device for unidirectional passage of current during starting of the fluorescent lamp. The starting device comprises of Triac, silicon controlled rectifier or the like diode and at least one preset resistor. Two sets of output terminals of the starting device are connected to the fluorescent lamp or other discharge lamps. The starting device is connected to the power source.

Abstract: For coupling one, or more, gaseous discharge lamps to a high-frequency AC power-source a ballasting (current-capacitor, and a transformer having a primary winding coupled to the high-frequency AC power-source by the first capacitor and a secondary winding coupled to the gaseous discharge lamp by the second capacitor.

Abstract: A single-ended ballast circuit employs a power-factor-correcting network (510); a DC power supply (512); a free-running oscillator (516); a transistor (518); a current-limiting (ballasting) network (520); and two fluorescent lamps (524). The transistor (518) is configured as a switch connected to be responsive to a signal generated (630) by the oscillator (516) and operative to periodically couple a line (734) to a circuit common. The current-limiting (ballasting) network (520) includes an inductor or transformer (740) having a primary winding (744), connected between a DC power-supply potential and the line (734), and a secondary winding (746); a first capacitor (750), connected between the line (734) and circuit common; an inductor (752); a second capacitor (756), connected in series with the inductor (752) across the secondary winding (746); and a third capacitor (754), connected in series with the lamps (524) across the second capacitor (756).

Abstract: A circuit for starting and operating fluorescent lamps from an a-c low frequency power source includes a reactive ballast means connected to ballast the lamps and having a non-linear characteristic for producing a plurality of harmonics of the power source frequency, and a capacitor and a cathode heating transformer connected in series and connected to receive power from said ballast means and resonant in a frequency range encompassing a plurality of said harmonics. This resonant voltage is applied across the lamps to aid the starting of their discharge and thereafter the lamps operate at the a-c power source frequency. The aforesaid resonance frequency range preferably is broad enough to encompass several harmonics of the power source frequency, for example the third through the ninth harmonics (180 to 540 Hz for a source frequency of 80 Hz). Preferably a switch is connected in series with the capacitor and cathode heating transformer for opening the cathode heating circuit when the lamps are operating.

Abstract: A power supply circuit for an electric discharge lamp driven by an A.C. power supply has a regulating transformer connected in parallel with a current limiting reactor and an electric discharge lamp interconnected in series. The tap of the regulating transformer is connected by a condenser and an auxiliary reactance interconnected in series to the connection between the current limiting reactor and the electric discharge lamp. By adjusting the tap of the regulating transformer the performance of the lamp can be influenced within a wide range. In place of the regulating transformer an electronic phase shifter may also be used, which is particularly advantageous when regulating speeds are required that cannot be achieved by means of an electromechanically adjustable regulating transformer.

Abstract: An ignitor or starting circuit for a high pressure arc discharge lamp including a voltage sensitive bidirectional switch and an impedance with a resistor and inductor in series circuit. An additional capacitor is connected in parallel across the voltage sensitive switch and the resistor.

Abstract: An inverter-type electronic fluorescent lamp ballast powers a fluorescent lamp with a sinusoidal current that is modified by insertion of a measured amount of properly phased third harmonic current, thereby attaining a lamp current crest factor that is substantially better than the 1.4 crest factor associated with a purely sinusoidally-shaped current.

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 fluorescent lamp ballast comprises a self-oscillating inverter with saturable transformer means in its positive feedback circuit. The saturation flux density of the magnetic material used in this saturable transformer means determines the frequency of inverter oscillation. A permanent magnet is rotatably mounted adjacent the saturable transformer means and is used by way of cross-magnetization to adjustably affect the saturation flux density of the magnetic material, thereby correspondingly to adjust the frequency of oscillation: the more cross-magnetizing flux provided to the magnetic material from the permanent magnet, the smaller the saturation flux density and the higher the frequency of oscillation.Current for the fluorescent lamp is attained from the inverter's squarewave voltage output by way of a series-excited parallel-loaded tuned L-C circuit, thereby providing for a lamp current of magnitude dependent upon the frequency of inverter oscillation.

Abstract: In a power-line-operated electronic inverter-type ballast for a fluorescent lamp, a series-connected L-C circuit is connected directly across the otherwise unfiltered output of a full-wave rectifier that provides DC voltage to the inverter. This L-C circuit is tuned to series-resonance at 120 Hz, thereby effectively shorting-out the fundamental component of the 120 Hz ripple that otherwise would be present on the DC voltage. The result is a fairly well-filtered DC voltage obtained without the use of the conventional and often short-lived electrolytic capacitor. This particular method of reducing the amplitude of the ripple voltage results in a particularly high power factor in respect to the power drawn by the ballast from the power line.

Abstract: Electronic ballasts are essentially composed of a series connection of a harmonic filter that has its input side connected to the AC line, a rectifier and an inverter to which is connected at least one load circuit composed of a series circuit of an inductor and a parallel circuit composed of a fluorescent tube and a capacitor. When a high electric tolerance is required of such a ballast in view of a desired increase in the power factor, standard circuit designs required a relatively expensive storage capacitor that smooths the AC rectified line voltage. In order to be able to use a storage capacitor that has a lower electric tolerance in comparison to the required voltage tolerance of the ballast, a storage capacitor is incorporated into one of the two capacitor branches of the inverter which is composed of a switch bridge arrangement having two switch branches and two capacitor branches, this storage capacitor being connected in series with the actual load.

Abstract: A novel lighting equipment for providing bright illumination with limited surge, including a capacitor connected in parallel with an incandescent lamp, the capacitor having a capacitive reactance lower than the resistance of the filament at ambient temperature; an impedance having a time constant connected between the capacitor and an ac source; and means for rectifying the current from the ac source.

Abstract: Apparatus for starting and operating a high pressure discharge lamp includes a pair of input terms for connection to a high frequency inverter. A step-up transformer couples the input terminals to a pair of output terminals for connection of the discharge lamp. A switching arrangement including a voltage-multiplier circuit, is coupled to the primary winding of the transformer and includes a first branch comprising a first capacitor and a diode and a second branch comprising a diode. Between the first capacitor and the diode of the first branch is connected a third branch comprising a semiconductor switch such as a SIDAC. The first branch is connected through the transformer coil to a first supply source connection point. The second branch is connected to a tap point of the coil. The first and the second branch are connected via a common impedance including second capacitor and an inductor to a second supply source connection point.

Abstract: A fluorescent lamp is connected in parallel with a resonant L-C circuit powered by a series-applied high frequency voltage from a self-oscillating inverter power supply. The frequency of the series-applied voltage is about 33 kHz during the brief initial period before the lamp ignites, but falls to about 30 kHz after the lamp has ignited. As a result, the detuning taking place in the L-C resonant circuit due to changing parallel-loading is compensated-for by correspondingly changing the frequency of the series-applied voltage. This detuning effect is particularly pronounced in situations where there is a large magnitude-ratio between the lamp's ignition voltage and its operating voltage.

Abstract: A DC/AC converter for igniting and supplying a gas discharge lamp (1). The converter has two input terminals (C, D) intended to be connected to a DC voltage source, said input terminals (C, D) being connected together by means of a series arrangement including a load circuit comprising at least an induction coil (10) and a parallel arrangement of the lamp and a capacitor (12), as well as a first semiconductor switching element (13). The load circuit is shunted by a circuit comprising a second semiconductor switching element (14). The semiconductor switching elements (13, 14) are rendered alternately conductive and non-conductive by means of control circuits (13a, 14a). A second capacitor (11) is arranged in series with the induction coil (10) and the lamp. The second capacitor is shunted by a third switching element (15) which is non-conductive during the pre-heat period of the lamp electrodes (2, 3) and is conductive at least during ignition of the lamp.

Abstract: A controller operates in pre-ignition and ignition phases to obtain stable and reliable control of operation of a half-bridge DC-AC converter in a frequency range which is offset from a resonant frequency of an output circuit which includes a transformer and capacitors and which couples the converter to a fluorescent lamp load. The converter is supplied with a DC voltage from a switched-mode DC-DC supply of a pre-conditioner circuit which responds to a full-wave rectified AC voltage and which is supplied with pulse-width modulated gating pulses from the controller, preferably at a frequency which is the same as that of the converter. The controller monitors signals from the output circuit and pre-conditioner circuits and exercises control to reliable starting and highly efficient lamp operation and to obtain an in-phase proportional relationship of input voltage and current waveforms.

Abstract: A ballast control apparatus for an electric discharge lamp comprises a first series circuit including a first winding of an AC supply voltage transformer, a first winding of a ballast transformer, a lamp current sensing resistor and the lamp. A current sensing transformer has a first winding parallel to the resistor. A second winding of the supply voltage transformer, the ballast transformer and the current sensing transformer are connected in a second series circuit. A signal voltage proportional to lamp power is derived by adding together the voltages induced in the three series-connected second windings. A second signal voltage proportional to lamp voltage is derived across the series combination of the second windings of the ballast transformer and the supply voltage transformer. The voltage induced in the second winding of the current sensing transformer is proportional to lamp current.

Abstract: The inventive power supply converts the low-frequency alternating current source into high-voltage direct current. An induction windings network series connected to the fluorescent tube provides a feedback signal to a pair of bridging transistors which then respectively alternates to be on or off to output a high-frequency, high-voltage signal for the tube to use. The network is connected so that the inductors provide the feedback signal, the signal having a resonant frequency suitable for activating the tube. The light emitted in accordance with this invention is continuous, due to the inventive feedback, in comparison to the light emitted by a fluorescent tube utilizing a transformer and a starter.

Abstract: Disclosed is a method and apparatus for reducing radiated interference from a light source wherein a filter device is coupled across the light source after a predetermined time has expired from the starting of the light source. In this way, the filter does not interfere with the starting of the light source, however, after being coupled, the filter prevents radio frequency interference generated by the light source from radiating from the light source and associated wiring and interferring with nearby radio receiving equipment.

Abstract: In a method or combination, a DC voltage supply, a converter including a series or a parallel resonant circuit for converting the DC voltage to a sinusoidal current, and a load including at least one fluorescent lamp responsive to the sinusoidal current to effect excitation of the lamp.