Abstract: A circuit, including an electrical load such as a fluorescent lamp, energized through an inverter which is in turn energized from a standard household alternating current voltage source. The output of the inverter is of a low voltage, low current and high frequency. This power is then transmitted by a low current voltage link, in the form of a flexible small gauge, jacketed wire conductor connected across the outputs of the inverter, to the input terminals of a compact step-up transformer located a distance away from the inverter. The power created by the step-up transformer is converted to usable power by the electrical load. The low voltage link need not be enclosed in a raceway.

Abstract: In an electronic ballast for at least one fluorescent lamp equipped with heatable electrodes, the heatable electrodes must be adequately preheated before the actual ignition of the fluorescent lamp. Given a high-frequency preheating of the heating electrodes that is usually employed and given the utilization of a frequency shift of the high-frequency of the D.C.-A.C. converter, relatively long preheating times on the order of magnitude of >1.2 second result. In order to be able to significantly reduce the preheating tifme below 1 second, it is proposed that a D.C. path be provided wherein the heating electrtodes are connected in series with the secondary winding at the secondary side of a transformer and to connect this D.C. path to the operating D.C. voltage during the preheating phase via controlled switches.

Abstract: A self-oscillating half-bridge inverter is powered from a power-line-operated DC voltage source. The inverter is loaded by way of a series-tuned high-Q LC circuit connected across its output. A pair of fluorescent lamps is series-connected across the tank-capacitor of the LC circuit. The inverter has two bipolar transistors, each driven by an associated saturable current transformer that provides for a transistor ON-time dependent upon the magnitude of an associated bias voltage. One of the transistors has a control arrangement connected in circuit with its associated saturable transformer and operative to control the magnitude of its associated bias voltage. As the magnitude of this bias voltage is controlled, the magnitude of the voltage across the tank-capacitor, as well as of the current available therefrom, is correspondingly controlled.

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 hot restart circuit includes a storage capacitor and SCR connected across a tapped portion of a ballast with a breakdown device to start the SCR. A charging circuit for the storage capacitor includes a diode, pumping capacitor and choke in series from the ballast tap to the AC line and a further diode interconnecting the capacitors. The pumping capacitor increases the charge on the storage capacitor in a step-wise fashion until the breakdown voltage is reached, whereupon starting pulses are applied to the lamp.

Abstract: A discharge lamp lighting apparatus according to this invention includes an inverter circuit for supplying a high frequency power source to a discharge lamp having one of different ratings, a voltage detecting coil of an inverter transformer for detecting a load voltage applied from the inverter circuit to the discharge lamp, a current transformer for detecting a load current supplied from the inverter circuit to the discharge lamp, and a control section and an oscillation circuit for controlling the power source supplying operation of the inverter circuit based on detection outputs of the voltage detection coil and current transformer.

Abstract: A multipurpose fluorescent light device suitable for use with power sources of 12 volts DC and 220 volts AC without having to use a voltage transformer, comprising a fluorescent lamp, a pair of antivibration covers, a starter switch, a circuit board assembly, a pair of positive and negative bypassing connections, a 120/220 voltage reduction wire, a 12 volt power cord, a transparent, heat-resistant plastic tube and a hook.

Abstract: A circuit arrangement suitable for operating a high-pressure discharge lamp (80) in conjunction with a controlled current limiter (6) by means of a control signal which is at least composed of the sum of a lamp-voltage-dependent signal part and a lamp-current-dependent signal part. The invention, the absolute value of the lamp-current-dependent signal part is chosen to be smaller than the absolute value of the lamp-voltage-dependent signal part. The circuit arrangement provides a rapid control, which keeps the lamp voltage substantially constant.

Abstract: An inverter includes a DC voltage source for supplying a DC voltage. A switching transistor switches the DC voltage supplied from the DC voltage source. A parallel resonant circuit receives the DC voltage switched by the switching transistor and generates an AC output. A self-excited oscillator includes a detector for detecting at least part of the AC output from the resonant circuit for supplying the detection output between the base and emitter of the switching transistor so as to control the ON and OFF of the switching transistor and supplying a base current to the switching transistor. A variable impedance element includes a series circuit comprised of a variable resistance element and a capacitor for changing the resistance value of the variable resistance element, thereby to change the combined impedance value to change the ON period of the switching transistor.

Abstract: In accordance with the present invention, a control device for energizing a lamp circuit including gaseous discharge lamps includes a power source having a variable amplitude varying in time. A control circuit is provided for producing a variable pulse width control signal. A switch is responsive to the variable pulse width control signal for providing a switched output from the power source. The switched output has a pulse width proportional to the variable pulse width control signal for supplying power to the lamp circuit. An inductor is interconnected between the switch and the lamp circuit. The inductor includes a first winding with a center tap for receiving the switched output from the switch for balancing the voltage and current applied to the lamps within the lamp circuit. The inductor further includes a second winding connected to the lamp circuit for providing constant lamp brightness regardless of amplitude variations in the source voltage.

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

Abstract: The invention provides a rare gas discharge fluorescent lamp device which is long in life and high in brightness and efficiency. The lamp device comprises a rare gas discharge fluorescent lamp including a bulb having rare gas such as xenon, argon or krypton gas enclosed therein, a fluorescent layer formed on an inner face of the bulb, a reflecting film formed on an inner face of the fluorescent layer, and a pair of electrodes located at the opposite ends of the bulb. The lamp device further comprises a power source for applying a voltage across the electrodes, and pulse voltage forming means connected between the electrodes and the power source for forming a dc pulse voltage from a voltage supplied from the power source. The dc pulse voltage thus formed is applied across the electrodes to cause the lamp to be lit.

Abstract: A method of and apparatus for supplying high frequency alternating current to a fluorescence lamp. For eliminating a so-called striation phenomenon, a direct current component is induced in the high frequency alternating current passing through a lamp (8). The circuit means inducing said direct current component comprise a capacitor (3), connected in series with the lamp and having a diode (4) or the like connected in parallel therewith.

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

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

Abstract: An apparatus for use in dimming florescent lamps by alternating cathodes operated with pulsating unidirectional arc currents for a duration that is long relative to the filament thermal time constant, but short in relation to the mercury migration time constant of the florescent lamp. The invention provides apparatus using full bridge switching and full bridge clamping topology in a trigger driver as well as a power driver to prevent low voltage power supply "ride up". The invention further provides means for sensing cathode heater current to detect a failed cathode and to control the phase switching to a good cathode if a cathode failure occurs. The invention further provides apparatus for a balanced-to-group ground lamp drive voltage for improved ignition of the lamp plasma and better lamp luminance uniformity when the lamp is operated dimly. A logarithmic amplifier is provided in a closed loop operation for analog compression and also to provide a logarithmic dimming response.

Abstract: To prevent long-time current flow through a positive temperature coeffici resistor (KL) included in the heater circuit of one or more fluorescent lamps (LP, LP1, LP2), a relay is connected in circuit with the PTC resistor (KL), which will respond when the voltage across the capacitor (C4) reaches the level of d-c voltage derived from a relay rectifier (GL) and coupled to the PTC resistor itself. The relay operates a switch contact (S) which interrupts the current flow through the PTC resistor; the flow through the relay is small in comparison with the current flow through the PTC resistor, thereby saving energy and decrease in the heat loading on the circuit structure.

Abstract: A circuit is disclosed which is capable of positively shifting a gas discharge lamp from its off-state to its on-state without emitting light flashes and further positively maintains the gas discharge lamp in its on-state when first ignited. The circuit contains an oscillator device which generates and supplies an oscillator signal of a specific oscillator frequency from two output terminals of the oscillator device. It also contains a current limiting device an a parallel-resonance circuit comprising a capacitor and an inductor. The parallel resonance circuit has a frequency of resonance substantially identical to the oscillator frequency. The current limiting device and parallel-resonance circuit are connected in a series configuration across the output terminals of the oscillator device. Further, the gas discharge lamp is connected across or in parallel with the parallel-resonance circuit.

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 starting and operating circuit for a discharge lamp in which the ballast reactance includes first, second and third coil segments with the third coil segment comprising part of the ignitor circuit and being electrically connected between the first and second coil segments.

Abstract: A power-line-operated ballast for two fluorescent lamps has a self-oscillating half-bridge inverter whose 30 kHz squarewave output voltage is switchably connected either with an auxiliary transformer and/or with a series-resonant L-C circuit. The lamps are series-connected across the tank capacitor of the L-C circuit; the lamps' cathodes are connected with individual outputs of the auxiliary transformer.When power is initially applied to the ballast, only the auxiliary transformer is connected with the inverter output, thereby providing heating power to the lamps' cathodes. After about 1.5 second, the L-C circuit is automatically connected with the inverter output, and the lamps then ignite in ordinary Rapid-Start manner. The auxiliary transformer is automatically disconnected at the time the L-C circuit is connected, thereby providing for extra high efficiency operation.In the event the lamps become disconnected or inoperative, the inverter will become disabled within about 15 milli-seconds.

Abstract: A rapid start fluorescent system which has its starting capacitance connected to a tap on the secondary of the ballast transformer which tap is located at a predetermined number of turns of the secondary.

Abstract: To provide enhanced starting voltages for fluorescent lamps operating, for xample, from 110 V power networks through a rectifier, and in which a high-frequency oscillatory circuit is used which includes a ring core transformer (TR1, TR2, TR3) operated under saturation conditions, and controlling switching transistors (T1, T2), which have emitter-resistors (R4, R5) connected thereto to stabilize the operation of the circuit and of the transistors, at least one diode (FIG. 4: D4, D5) is connected in parallel to at least one of the emitter resistors; for some circuits (FIGS. 2-4) a diode, or two diodes (D6, D7, D8, D9) can form the emitter-resistors or resistors.

Abstract: In a power-line-operated electronic ballast for a gas discharge lamp, an inverter converts a DC supply voltage to a high frequency current-limited operating voltage for a fluorescent lamp. The DC voltage is obtained, at least in part, by forward inductive-discharge conversion of full-wave-rectified unfiltered power line voltage; which forward conversion is accomplished by high frequency switching of an energy-storing inductor; the switching being done by the very same inverter that provides the high frequency lamp operating voltage. As an overall result, power is drawn from the power line with a power factor higher than 98% and with a total harmonic distortion under 10%.

Abstract: For a starting device to acquire an ability to start a discharge tube efficiently, allow the light from the discharge tube to be regulated effectively over a wide range, and fit versatile use with discharge tubes of a varying kind, this invention causes the frequency of pulses of a fixed duty ratio issued by pulse generating means to be freely adjusted by adjusting means and consequently enables high-voltage applying means to apply a high voltage of a frequency proper for the pulses to the discharge tube and effect efficient and stable start of the discharge tube. Since the frequency of high voltage for application to the discharge tube is adjusted by the adjusting means, the regulation of light is attained over a wide range and the starting device itself is enabled to fit versatile use with discharge tubes of a varying kind.

Abstract: A portable high pressure sodium lamp lighting system is mounted on a mobile cart, the cart carrying a mobile power supply in the form of a automotive type battery. The portable lighting system employs a standard high pressure sodium luminaire designed to be driven by 115 volt 60 cycle utility generated power. A DC to AC converter is employed which converts the DC battery supply to a 115 volt simulated 60 cycle supply. The AC characteristic is simulated by generating a quasi-square wave form which approximates a 60 cycle characteristic when driving the luminaire.

Abstract: A fluorescent lamp dimmer, for use with one or more fluorescent lamps where large ratios of luminous differences are required, which includes apparatus for powering the arc current for the fluorescent lamps from a source of pulsating voltage of variable pulse width and variable frequency both of which can be changed by relatively small amounts and still produce very large changes (15,000:1) in luminescence.

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: An electronic stabilizer for a fluorescent lamp characterized by comprising noise filter, voltage multiplying rectifier, inverter with the first and second register, first and second high speed starter in the inverter, and input trigger connected with the commercial power source to provide inexpensive, simple, and stable electronic stabilizer by the limited current and better practice at oscillating high frequency.

Abstract: An inverter is made up of a parallel circuit as a voltage resonance circuit, and a first diode, which are connected in series between both ends of a power source. The parallel resonance circuit includes the primary winding of an output transformer of the leakage type, and a resonance capacitor. The first diode is connected at the cathode to the primary winding of the output transformer. The secondary winding of the output transformer is coupled with a load such as a discharge lamp. The cathode and anode of the first diode are respectively connected to the collector and emitter of a transistor. A series circuit of a second diode and capacitor is connected across the collector-emitter path of the transistor. The second diode is forwardly arranged with respect to the transistor. A voltage detector comprises the capacitor and two resistors which are connected in series, and connected across the capacitor. The output voltage is derived from the node of those resistors.

Abstract: A high frequency power circuit for energizing at least one gas discharge lamp with two filaments. The circuit is adapted to be supplied with power from a DC voltage source, and comprises semiconductor switching elements and control means for the semiconductor switching elements. The circuit also comprises a high frequency transformer having at least one primary winding which, in operation, is supplied with an AC voltage signal by the semiconductor switching elements. The transformer has at least one secondary main winding and secondary auxiliary windings. The secondary auxiliary windings, in operation, energize the filaments of the at least one gas discharge lamp. The control means are adapted to disconnect, in a stand-by mode, by at least one controllable switching means. The connection between the at least one secondary main winding and the at least one gas discharge lamp.

Abstract: In a power-line-operated electronic ballast, an inverter converts a DC voltage to a high frequency current-limited operating voltage for a fluorescent lamp. The DC voltage is obtained, at least in part, by forward conversion of full-wave-rectified unfiltered power line voltage; which forward conversion is accomplished by high frequency switching of an energy-storing inductor, the switching being done by the very same inverter that provides the high frequency lamp operating voltage. As an overall result, power is drawn from the power line with a power factor higher than 98% and with a total harmonic distortion well under 20%.

Abstract: In a fluorescent lamp device, a discharge tube is made by arranging electrodes at the ends of a glass tube, sealing mercury and a rare gas into the glass tube and coating the inner surface of the glass tube with a phosphor, and an amalgam forming material is disposed close to one or the other of the ends of the discharge tube. This fluorescent lamp is operated with a d.c. current using as the anode the electrode arranged on the discharge tube end side where the amalgam forming material is located.

Abstract: An economical power-reducing circuit for either a fluorescent lighting fixture or for a high-intensity, low-voltage incandescent lamp has an electrolytic capacitor and a diode connected in parallel with the capacitor. When used in a fluorescent lamp fixture, the circuit reduces power consumed by the fixture, both when used as a lamp substitute or as an attachment that does not eliminate a lamp. When used with a high-intensity, low-voltage incandescent lamp, the power-reducing circuit eliminates a transformer, thus saving both cost and weight. It also should provide a power saving at no reduction in brightness, and should prolong the life of in the incandescent lamp.

Abstract: A ballasting system for powering an array of flourescent lamp assemblies, as in a sun tanning apparatus, comprises an electronic frequency converter adapted to convert ordinary 60 Hz power line voltage into two non-current-limited high frequency outputs: a first output of 400 Volt/30 kHz sinusoidal voltage provided between a first pair of distribution conductors, and a second output of 50 Volt/30 kHz sinusoidal voltage provided between a second pair of distribution conductors. Each lamp assembly comprises two mutually parallel-disposed series-connected fluorescent lamps. The 50 Volt/30 kHz voltage is provided to the one end of this assembly and is used by way of an isolation transformer means to provide cathode heating power for the two lamp cathodes located near that end.

Abstract: A current fed half-bridge parallel resonant inverter for powering one or more discharge-type lamps is comprised of a bifilar wound current feed choke placed in series with a transformer whose secondary resonates with a capacitance placed across the secondary. The bifilar current feed choke is connected in such a way as to insure that that current flows through alternate windings on alternate half cycles of the inverter. Each half of the primary circuit is comprised of one winding of the current feed choke, transformer primary winding, and a switch such as a transistor or the like. An inherent feature of the half-bridge design is that the two halves of the primary circuit operate at different DC offsets. A means is provided for alternately switching the switches of each half of the primary circuit on and off through additional windings of the transformer.

Abstract: A lighting arrangement comprises;(i) a plurality of pairs of mutually parallel-oriented fluorescent lamps, each pair of lamps adapted to be powered from 30 kHz/240 Volt by way of a high-Q series-resonant L-C ballasting circuit;(ii) a relatively low-power frequency converter connected with the power line and operable to provide power for heating the cathodes in these fluorescent lamps, thereby conditioning the lamps for easy starting;(iii) a relatively high-power frequency converter also connected with a power line and operable to provide the 30 kHz/240 Volt required for operating the plurality of pairs of fluorescent lamps by way of the high-Q series-resonant L-C ballasting circuit; and(iv) delay means operable to prevent the 30 kHz/240 Volt provided by the high-power frequence converter from being applied to the fluorescent lamps until after power has been applied to heat the lamp cathodes for at least one second.

Abstract: A micro processor based Lighting Control System and Module is disclosed which controls lighting circuits to operate at reduced power levels to obtain the most efficient lighting level for a given task to obtain conservation of energy and a financial savings. After the control is set by the user for a selected lighting level reduction, a selected power is applied; and, the system, through its micro processor and control circuitry, continuously monitors the power applied, and maintains a desired power level to maintain the lighting level desired.

Abstract: An electric arrangement for igniting and supplying a gas discharge lamp (13) has two input terminals (1, 2) intended to be connected to an AC power supply source. The output terminals of a rectifier bridge (4, 5, 6, 7) are connected in the operative state of the lamp to a DC/AC converter having two input terminals (A, B), one terminal (A) of which is connected to the other terminal (B) at least via a series arrangement of a first semiconductor switching element (9) and a load circuit comprising at least an induction coil (10) and the discharge lamp (13) as well as a capacitor (15). The load circuit and capacitor are shunted by a circuit comprising a second semiconductor switching element (16) and a parallel arrangement of a third semiconductor switching element (18) and a diode (17). The first two semiconductor switching elements are shunted by a buffer capacitor (8).

Abstract: This illumination lamp (5) includes a discharge tube (6, 7), a standardized base (10) and an intermediate element (9) arranged between the tube and the base. The lamp is characterized in that an electronic circuit (32) transforming the low frequency of the distribution network into a high frequency for energizing the tube is entirely electronic circuit is made up of a printed circuit in the form of a disc (30) bearing vertically arranged circuit components. The lamp, which is of greatly reduced dimensions is intended to replace an incandescent lamp.

Abstract: A ballast having a converter for converting input power into DC at a high frequency and a commutator for converting the DC to AC at a low frequency to cause light emission from a gas discharge lamp. The converter also contains a transformer for converting the input AC to a low voltage AC for heating the filaments in the lamp. Current and Voltage sensors associated with the commutator provide feedback to control circuitry which allows power conversion after the filaments heat and the voltage to the lamp to increase to the voltage required to start the lamp even when different starting voltage requirement lamps are used. After the lamp starts, the lamp is soley current mode controlled. By frequency modulation of the commutator, both power and crest factor can be controlled.

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 circuit arrangement for operating a high-pressure sodium lamp is provided with two lamp connection points. The circuit arrangement comprises a controlled main switching element, a control electrode of which is connected to a control circuit. The circuit arrangement is provided with a measuring impedance in series with a lamp connection point and with a measuring impedance parallel to the lamp connection points. The measuring impedances are connected to the control circuit. A combination of a resistor and a capacitor is further connected to the control circuit and this combination is connected in series with one lamp connection point.

Abstract: A control system for lighting a bank of fluorescent lamps, includes input terminals (10, 11) for a mains voltage (e.g. 240 v) and output terminals (20, 21) to which the bank of lamps is connected. A transformer (T1) provides a reduced voltage (216 v) as compared to the mains supply voltage. The transformer (T2) provides a supplementary voltage (24 v). Upon start up of the circuit, a control circuit (CC) operates contact (A1) to energize the transformer (T2) so that terminals (20, 21) receive both the reduced voltage from (T1) and the supplementary voltage from (T2) (i.e. 240 v) which is sufficient to ignite the fluorescent lamps. The control circuit (CC), after a predetermined delay (e.g., 15 seconds), switches contact (A1) to disconnect the supplementary voltage from (T2). The lamps then continue to operate on the reduced voltage (216 v) thereby reducing the power consumed by the lamps.

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

Abstract: A DC/AC converter (8) having a half bridge circuit for igniting and feeding a gas and/or vapour discharge tube (1). A starting capacitor (94) of this converter is connected between a junction (A) between two branches--each comprising a semiconductor circuit element (60 and 61)--of the half bridge circuit on the one hand and a center tapping (E) of a voltage divider (90, 91) on the other hand. As a result, the converter (8) starts satisfactorily and hence the discharge tube (1) readily ignites, moreover undesired starting pulses during the operating condition are avoided.

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

Abstract: A full-bridge inverter ballast for a fluorescent lamp comprises two pairs of switching transistors and is conditionally operable to self-oscillate in either of two modes: a first mode wherein one of the two pairs of switching transistors self-oscillates in manner of a half-bridge inverter and powers the thermionic cathodes of the fluorescent lamp, and a second mode wherein both pairs of transistors self-oscillate in manner of a full-bridge inverter and then powers the main gas discharge of the fluorescent lamp. The first mode gets initiated immediately upon applying power to the ballast, but the second mode does not get initiated until about 1.5 seconds after the initiation of the first mode. The way, the cathodes will have become fully thermionic prior to applying main power to the fluorescent lamp.