Abstract: A method for reducing the harmonics created by rapid-start fluorescent lamp stabilizer balance systems is accomplished by increasing the number of turns of the secondary winding of the transformer so as to decrease the secondary current to approximately 40 to 90 percent of the rated lamp current. This method increases the impedance and reduces the secondary current between 40 and 90 percent of the rated lamp current. While the absolute value of the illuminous intensity is lowered by the reduction in the secondary current, the lamp maintains a uniform brightness of illumination. This method decreases the distortion in the primary wave form which decreases the distortion effect on sensitive electronic systems which may be connected to the same electrical power source or may be in the area near the stabilizer.

Abstract: A pulse generator for a stable output pulse voltage obtains a high voltage pulse with a charge accumulated in a capacitor and discharged at a discharge gap made ON, wherein a pulse energy source and a trigger source for conduction of the discharge gap are separately provided, so that the discharge gap will be conducted by a boosting action of the trigger source when a predetermined value is reached by a voltage of the pulse energy source.

Abstract: A high-pressure gas discharge lamp is connected on one side to a lead across the secondary winding of a starter transformer and to a second lead on the second side. Starting energy is applied with a pulse. For this purpose, a controllable switch which becomes conducting on reaching a certain voltage or is connected by a drive is provided in series with the primary winding. A capacitor connected in parallel to the series connection is charged by voltage U between the input terminals across a resistor connected in series and a diode. An input circuit provided between these input terminals of the starter has a capacitor, a protective element or a combination of the two for protection against voltage peaks.

Abstract: An electrical circuit for simultaneously energizing at least a pair of CCFLs that are connected in series. The circuit also includes a transformer having a primary winding adapted to receive an alternating current. A secondary winding is coupled in series with the CCFLs to energize their operation. A shunt capacitor, connected in parallel across one CCFL, significantly reduces the peak voltage that must be applied across the CCFLs. Usually, the circuit also includes an isolation capacitor connected in series between the CCFLs and the secondary winding of the transformer. The isolation capacitor provides both DC blocking and electrical isolation between the secondary winding and the CCFLs.

Abstract: A flash circuit for a low cost camera in which a voltage dependent resistor is employed as a flash capacitor charge voltage sensing device to perform a control effect in the flash circuit, such as turning on a flash ready indicator light or activating a oscillation terminating device to arrest self oscillations in a flash charging circuit.

Abstract: The present invention discloses an electroluminescent panel and a power supply circuit for applying voltages of alternating current to the electroluminescent panel. The power supply circuit is comprised of a voltage converter, an electric power source, a charge controller for controlling the transfer of energy from the power source to the electroluminescent panel, and a discharge controller for controlling the transfer of energy from the electroluminescent panel to the power source.

Abstract: An apparatus for retrofitting an HID light fixture is described in several embodiments. The apparatus is coupled in series with the secondary winding and the HID lamp of the HID light fixture. A first retrofit capacitor replaces the light fixture capacitor of the HID light fixture. A switching device is coupled in series with a second retrofit capacitor and couples the first and second retrofit capacitors in parallel in response to a normal power mode control input so that the HID lamp provides normal intensity lighting at normal power. The switching device uncouples the first and second retrofit capacitors from being in parallel in response to a low power mode control input so that the HID lamp provides low intensity lighting at low power.

Abstract: A stereo audio encoding method for encoding left and right original signals to a left and right reproduced signals for suppressing a loss of quality in the reproduced audio signal. The correlation between the right and left channel signals is determined, and the phase of each signal is compared. If the two signals have the same phase, a modified scale factor is calculated based on a power equalization method, but if the two signals are in opposite phase, another modified scale factor is calculated based on an error minimization method. The modified scale factors are used for calculating the reproduced signals.

Abstract: A switching power supply 38 for use in a switched anode, field emission flat panel display includes energy recovery modules 48.sub.R, 48.sub.G and 48.sub.B for recovering energy from each anode electrode 50.sub.R, 50.sub.G and 50.sub.B of the display as the voltage on the anode V.sub.A is switched from a high level to a low level, and for restoring this energy to the anode as the voltage is returned from the low level back to the high level. Each energy recovery module 48 includes a capacitor 62 for storing charge and an inductor 60 for storing energy. During the deactivation period of each anode electrode 50, dc source 40 is uncoupled from anode electrode 50 and energy is transferred from the anode electrode 50 to inductor 60, and subsequently from inductor 60 to storage capacitor 62. During the re-activation period, energy transfers from storage capacitor 62 to inductor 60 and anode electrode 50, and subsequently from inductor 60 to anode electrode 50.

Abstract: An electronic flash device including a self-oscillating charging circuit, a momentary trigger for initiating oscillations of the circuit to charge a flash capacitor, and a voltage sensing device coupled directly between the circuit and the flash capacitor for arresting the oscillations when the capacitor is fully charged. The voltage sensor includes a zener diode in series with a neon ready-light, and switches on a transistor to ground the charging circuit and arrest the oscillations when the capacitor is fully charged. Actuation of the flash device automatically restarts the oscillations and recharges the flash capacitor. A process for recycling a single use camera having such an electronic flash device also is disclosed.

Abstract: The present invention discloses an electroluminescent panel and a power supply circuit for applying voltages of alternating current to the electroluminescent panel. The power supply circuit is comprised of a voltage converter, an electric power source, a charge controller for controlling the transfer of energy from the power source to the electroluminescent panel, and a discharge controller for controlling the transfer of energy from the electroluminescent panel to the power source.

Abstract: An inverter-type electronic ballast for a gas discharge lamp is powered by a DC supply voltage provided from a rectifier-filter combination connected with an ordinary electric utility power line. The absolute magnitude of the DC supply voltage is higher than the peak absolute magnitude of the power line voltage. The ballast includes an inverter circuit operative to provide an inverter output voltage of special trapezoidal-like waveshape; which output voltage is applied to a series-resonant combination of an inductor and a capacitor. The gas discharge lamp is connected in parallel with the capacitor. The inverter is driven by a voltage of special waveshape and controllable frequency. By controlling the frequency, the magnitude of the current supplied to the gas discharge lamp can be adjusted, thereby correspondingly adjusting the amount of light produced by the lamp.

Abstract: In an electrical circuit for feeding a fluorescent lamp, a serial resonant circuit is comprised of a first coil of a feedback-transformer, a resonant inductor, a coupling condenser, a first lamp cathode, a resonant condenser, and a first coil of an isolating transformer, this serial resonant circuit being connected between the output of an inverted rectifier, connected to a voltage supply source and one terminal of said voltage supply source, with a second coil of the isolating transformer being connected in parallel with the second lamp cathode. If the coils of the isolating transformer have the same number of loops, this connection of the second lamp cathode ensures that the same heating current will flow through both lamp cathodes, so that these will be heated equally. The parallel circuit of the second lamp cathode with the second coil of the isolating transformer is connected through a resistance with a terminal of the supply voltage.

Abstract: An electronic ballast circuit for discharge lamps, comprising a boosting transformer for applying a high voltage as a discharging voltage to the discharging lamps, the high voltage being induced in a main secondary winding of the transformer according to forward and reverse currents flowing through a primary winding of the transformer, a charging section for charging a voltage from an input power source terminal, first and second switching sections for repeatedly performing switching operations contrary to each other, a resonance section for allowing the forward current to flow through the primary winding of the boosting transformer when the first switching section conducts and allowing the reverse current to flow through the primary winding of the boosting transformer when the second switching section conducts, and a plurality of condensers, each connected between the secondary winding of the boosting transformer and a filament of a corresponding one of the discharge lamps, the condensers limiting amounts of

Abstract: An efficient ballast for Mini-fluorescent lamps, includes an inductor, in communication with a power source and constructed as transformer with only primary winding, a fluorescent lamp in series with the inductor, and a capacitor in series with the fluorescent lamp, and optionally may include a resistor in parallel with the coil, and a switch interposed between the capacitor and power source. The value of the capacitance may change based upon the degree of change in the supply voltage.

Abstract: The semiconductor device is composed of a thyristor and a MOSFET cascade-connected. The thyristor includes a bipolar transistor cascade-connected with the MOSFET, the base (p.sup.-- semiconductor region) of which is adapted to be punched through by the application of a working voltage. Thus, the thyristor can easily be latched and unlatched in response to the turn-on and turn-off of the MOSFET. Thus the semiconductor device can be securely on/off controlled by only the single gate (G) of the MOSFET. By using such semiconductor device as a switching element in a flash control device, a high performance flash control device with high flashing efficiency is provided.

Abstract: According to the invention there is provided a remote ballast circuit assembly comprising at least one ballast circuit; a housing having a top panel, an optional perforated bottom panel, two lateral side panels and a back panel, the panels defining a housing interior; the interior being divided into an upper chamber and a lower chamber, the upper chamber having exterior vent openings; at least one ballast coil in the ballast circuit disposed in the upper chamber; at least one resonating capacitor connected with the ballast coil disposed in the lower chamber; primary power connecting means for connecting primary power to the ballast circuit; and load connecting means for connecting a load to the ballast circuit. According to a further feature, the remote ballast circuit assembly according to the invention includes a hinged door panel hingedly attached to the housing for providing access to the housing interior.

Abstract: A power line-operated electronic converter is adapted to deliver a relatively constant magnitude high frequency signal to a load (113) and is operable to draw a substantially sinusoidal current from the AC voltage source (101). The converter has DC input terminals (B+, B-) having a capacitor (111) connected therebetween, first and second rectifier bridges (137, 138) coupled to the DC input terminals, a transistor inverter (131) coupled to the DC input terminals, a resonant oscillator circuit (135) coupled to the DC input terminals and to the transistor inverter employing a resonant inductor (117) and a resonant capacitor (114), and an input-output feedback implemented by coupling and modulation of a voltage developed across the resonant inductor to a voltage proportional to a difference of a voltage developed across DC input terminals and a voltage provided by a rectified AV voltage source.

Abstract: A circuit arrangement for operating a gas-discharge lamp is proposed, in which the high voltage for starting the gas-discharge lamp is generated by means of the energy stored in a transformer or capacitor. In order to obtain a steep rise in voltage of the starting voltage, the starting voltage is provided to the gas-discharge lamp via a voltage-controlled switch. A break-over diode, which has very short switching times, is proposed as the voltage-controlled switch. The starting circuit is switched off after starting. This circuit arrangement is also particularly suitable for starting gas-discharge lamps which are warm from operation. In consequence, it is particularly suitable for motor vehicle headlights.

Abstract: To eliminate the necessity for a saturated or air gap inductance to provide feedback circuit for a self-exciting oscillator including two active electronic switches (T1, T2) , for example MOSFETs, an auxiliary winding (HW1, HW2, . . . HW11) is inductively coupled to the resonance inductance (L2) present in the circuit for the discharge lamp (LP) anyway; and a pulse shaping - phase shifting network (R3, C3; R4, C4 . . . ) , devoid of inherent resonance, coupling the auxiliary winding to the active switching elements. The pulse shaping - phase shifting network is formed of a one or multiple-stage RC low-pass circuit, connected serially between the auxiliary winding and the control input, for example the gate, of the active switching element. The RC network can be constructed with variable elements, for example including PTC resistors, a varistor or the like, and may include a current source, protective circuits to protect against voltage peaks including Zener diodes.

Abstract: A power regulating ballast for gaseous discharge lamps operated from a source of high-frequency power incorporates a method in an apparatus which utilizes a distributed capacitance in combination with an inductor and includes a current feedback derived from charges in the current flow through the lamp.

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: For driving gas discharge lamps (102, 104) having heatable filaments (102A, 102B, 104A, 104B), a circuit (100) has an inverter (132, 134) and a series-resonant LC oscillator (150, 158, 170) forming a self-oscillating inverter. The oscillator output provides filament-heating current through the filaments in series, and drives arc current serially through the lamps. A feedback transformer (174) with a winding (172) connected serially in the filament-heating current path controls the operation of the inverter. A voltage clamp (180, 182) limits the voltage applied to the lamps. The circuit does not require an output-coupling transformer to couple the output of the self-oscillating inverter to lamps, thus avoiding the added cost that the use of such a transformer would bring, while providing efficient, substantially fixed frequency operation of a wide variety of lamp loads, together with the ability to address a number of lamp fault modes. Alternatively, the lamps may be driven in parallel.

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: An apparatus for operating discharge lamp. The apparatus includes a source of electrical power, switching devices for switching the electrical power, a control circuit for controlling the switching devices, a transformer having a primary winding for receiving the electrical power switched by the switching devices and a secondary winding for supplying power to the lighting apparatus, a resonant circuit including an inductor and a capacitor for regulating the frequency of the electrical power and a circuit for powering the control circuit, the powering circuit including a secondary winding on the inductor and an additional winding on the transformer connected in a differential manner.

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 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 ballast circuit includes a load circuit. A reservoir capacitor is effective to supply charge to the load circuit. A capacitive charge pump circuit is effective to transfer charge from a charge pump capacitive circuit to the load circuit and to the reservoir capacitor. The load circuit includes the primary winding of a transformer. A secondary winding of this transformer is for connection across a discharge lamp. In operation of the ballast circuit, the primary winding of the transformer drives the capacitive charge pump circuit.

Abstract: A circuit suitable for the instantaneous starting, continuation, and interruption of current through one or more gasfilled discharge tubes, in particular fluorescent lamps, is described. The circuit and lamp heaters are energized before instantaneous control can occur. One preferred silicon controlled rectifier (SCR) is used with a bridge rectifier. The SCR has the dual role of causing the capacitor to discharge through the pulse transformer, the secondary pulse voltage of which thereby causes the arc to strike immediately upon application of gate current, and then maintianing the lamp current as long as a supply of SCR gate current is provided. A second preferred control device, a TRIAC, is used without a bridge rectifier and again has a dual role of pulse-starting and maintaining current. This type of device is more conveniently arranged to provide for a dimming function as well. Applications include "flashing" advertising signs, general illumination, and signals.

Abstract: An electrical circuit used in conjunction with high power factor ballasts and quality fluorescent lamps to reduce the power consumption of a fluorescent fixture by an average of 40% with a lesser reduction of light output because of optimized current control through the discharge lamps increasing the efficacy of conversion of electricity to light, accomplishing this by means of a tuned inductor-capacitor resistor circuit, these along with a 1 to 1.3 impede current surges, transformer, add harmonics a circuit diode and feedback loop to reshape the circuit waveform for optimum performance of said lamps and optimum economic savings and payback through applicaiton of this technology to multiple fixtures in offices, factories, commercial buildings and stores.

Abstract: A lamp driver circuit is presented herein for driving a lamp circuit with an AC squarewave voltage at a relatively high frequency. The driver circuit includes a self-oscillating half-bridge circuit having a pair of input terminals connected across a DC voltage supply, which may be obtained from rectifying an AC voltage signal, and a pair of output terminals connected across a lamp circuit including a lamp, either a resistive lamp or a gaseous discharge lamp, to be energized. The circuit also includes a pair of capacitors connected together in series across the input terminals and having a junction therebetween connected to a first one of the output terminals. The bridge circuit also includes first and second switching transistors connected together in series across the input terminals.

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 bi-level ballast network is disclosed for operating an HID lamp at either a low power or standby level and at a high power or full light level. The network includes an unswitched capacitor connected to the transformer ballast coil and a switched capacitor connected to a solid state relay (SSR) circuit, the electronic components providing the switching therein being back-to-back SCR's. When the SSR is operated the contacts connected to the switched capacitor open or close at the next subsequent zero crossing of the applied ac source voltage. This changes the capacitance of the network to increase the power to the lamp or decrease the power thereto depending on the operating condition prior to the SSR being operated. Current, voltage and dvdt protection devices are also provided.

Abstract: A discrete device in which a capacitive and inductive function has been integrated is comprised of at least two insulated amorphous ribbons which are spirally wound to form a cylindrical toroid. Each of the amorphous metal ribbons is insulated from each other ribbon by a dielectric layer and wound in a stacked configuration to provide the capacitive function. Two conductive windings are then wrapped around segments of the cylindrical toroid to provide inductive and/or transforming functions as desired. A magnetic circuit is formed through the windings by the amorphous metal ribbons. A dielectric insulating layer between the ribbons is offset from the longitudinal edge of the ribbon so that the longitudinal edge of each ribbon is exposed. One ribbon has its longitudinal edge exposed on one surface of the toroid while another ribbon has its longitudinal edge exposed on the opposing surface of the toroid.

Abstract: The illumination device includes a charging part, an energy storage device, a flash tube and an amplitude control device, by means of which the energy storage device can be charged to different voltages. A time control device is superposed upon the amplitude control device. In consequence of the two control devices, the flash tube emits light with a predetermined color temperature as a function of the set amplitude and of the set flash duration. The color temperature can thereby be influenced in a controlled manner, with the maintenance of a very fine setting of the quantity of light, and can also be maintained constant independent of the quantity of light emitted.

Abstract: A low cost circuit addition in the form of a capacitor of suitable value provides effective starting and operation of rapid start, preheat, and instant start fluorescent type gas discharge lamps along with their standard A.C. operated ballast transformer auxiliary devices at reduced power levels to achieve energy conservation with a concomitant reduction in light output and can usefully employed in illuminated areas where a reduction in lighting level would not effect the utility of that particular area. The capacitor is connected in series with the ballast primary winding and is of such value as to cause ferro-resonance to occur in the ballast transformer primary circuit, thereby providing a voltage magnification effect to aid the lamp starting, or ignition, process i.e., during the time interval between circuit energization and production of a stable arc, and to thereafter operation of the lamp with reduced arc current.

Abstract: A device for boosting power supply voltage is provided with a transformer having a secondary winding which generates an elevated voltage when the power supply current is supplied to the primary winding, whereby the voltage generated in the secondary winding is supplied to a load while voltages corresponding to the inverse electromotive force generated in the primary winding are supplied to another load.

Abstract: A current control circuit for high voltage applications includes series-connected high and low voltage sources through which the current to be regulated flows. The low voltage source is a capacitor which is periodically recharged through a flyback transformer by a series of constant energy pulses having a very low duty cycle. The peak value of the flyback pulses are detected to provide a "condition signal" which is representative of the state-of-charge on the capacitor and can be used to protectively inhibit operation of the control circuit and can, in a variant of the circuit be used as an error control signal to maintain the current at a constant level. In the preferred embodiment a sensing capacitor is placed in parallel to the pulsed capacitor to detect the fluctuations in potential and form a sense current which is representative of the regulated current and which is used in a feedback loop to form a control signal for maintaining the regulated current constant.

Abstract: An electronic ballast circuit for fluorescent or other gaseous discharge lamps includes a resonant half-bridge inverter circuit. The source voltage to the inverter is a full-wave rectified line voltage together with a DC carry-over voltage for supplying power in the inter-cusp period of the recitified line voltage. A negative feedback circuit is responsive to lamp current to vary the inverter drive frequency and thereby regulate lamp current. The frequency response of the feedback loop is high enough and the gain-versus-frequency response of the inverter is such that lamp current and voltage are regulated to reduce the crest factor of lamp current to compensate for variation in the amplitude of the voltage across the semi-conductor switches.

Abstract: A DC/AC converter (30 to 72) for feeding a low-pressure mercury vapor discharge tube (15) comprises two series-connected main transistors (11 and 20) which, in the operating condition, are alternately conducting. The conduction times of the two transistors (11 and 20) are always kept equal to each other by means of an auxiliary circuit (70 to 72, 32a, 32b, 32c) which influences the operation of a timing circuit (32, 33). This prevents the occurrence cataphoresis in the lamp.

Abstract: Various embodiments of direct current (D.C.) ballasting circuits for low wattage high pressure sodium (HPS) vapor lamps are disclosed. In one ballast embodiment a negative going high voltage pulse is applied directly to the H.P.S. lamp cathode during the starting operation and the ballast circuit preferentially diverts a major portion of the HPS lamp current around a high-voltage transformer during normal operation so as to reduce the resistive heating of the transformer. In a second ballast embodiment, capacitors are arranged into voltage multiplying circuit for generating the high D.C. starting voltage along with diodes that reduce the power dissipation of the ballast circuit.

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

Abstract: A ballast for a fluorescent lamp including a tuned circuit in series with a pair of voltage input terminals to which an input AC voltage is applied. The tuned circuit includes a capacitor in series with an inductor, with the resonant frequency of the tuned circuit being approximately 1/2 the frequency of the input voltage. At start-up, the inductor is very highly reactive to provide a starting voltage which is applied to a fluorescent lamp coupled across the inductor. A positive temperature coefficient resistor is in series with the inductor to limit the current flow therethrough. The inductor forms a part of the primary winding of a transformer having a secondary winding providing the heater voltage for the lamp. A second primary winding of the transformer provides a power factor correction for the tuned circuit.

Abstract: Starting and operating method and apparatus for discharge lamps comprises a current-limiting and rectifying means which provides at its output a low-ripple current-limited direct current. To effect lamp starting, a series-connected inductor and capacitor form a high "Q" resonant circuit with the capacitor connected across the lamp to be operated. This starting circuit connects through a blocking capacitor and charging resistor across the low-ripple source of DC. A pair of transistors which comprise an oscillator are connected emitter-to-collector across the source of DC, with the common-connected emitter and collector connected to the blocking capacitor. A drive air-core transformer has separate feedback windings in the starting and operating circuits and drive windings are associated with the transistors. A trigger diode is used to initially pulse one of the transistors which initially oscillate to generate square waves having a frequency corresponding to the resonant frequency of the starting circuit.

Abstract: A DC/AC converter provided with two transistors (11 and 20) alternately conductive to supply current to an inductively stabilized discharge lamp (16, 15) to be connected to the converter. The lamp is connected in series with a primary winding (12) of a current transformer. A secondary winding (30, 31) of the transformer is connected to a timing circuit (32 to 35; 32' to 35') of a control device of the transistors. The timing circuit is provided with voltage-dependent elements, i.e. Zener diodes (35, 35'). The combination of the current transformer and the Zener diodes causes the frequency of the converter, during starting of the lamp, to be larger than during the operating condition of the lamp. This insures that the lamp electrodes are properly heated before the lamp ignites.

Abstract: A ballast for a sequence start series operating circuit that includes two rapid start gaseous discharge lamps. The circuit includes a transformer with a primary winding and a loosely coupled secondary winding, a series first capacitor for providing a leading current when both lamps have been ignited and are operating and a second capacitor shunting the second-to-ignite lamp to by-pass that lamp during ignition of the first-to-ignite lamp and thereafter to develop a voltage across the second capacitor sufficient to ignite the second-to-ignite lamp when current flows in the by-pass branch. The lamps are of a variety which produces an undesirable current peak in the second-to-ignite lamp on each half cycle because the shunting second capacitor dumps its charge accumulated during each half cycle into the lamp.

Abstract: Improved programming and control device for modified lead ballast for HID lamp. The basic ballast comprises a high reactive transformer and capacitor connected intermediate the transformer and lamp. An additional inductor and AC switch connect in parallel with the capacitor and the switch is opened and closed to vary the lamp current to control lamp output. The improved device comprises a parameter measuring means which measures a lamp operating parameter and converts same into output electrical signals. These signals are compared to a reference signal to generate error signals. The error signals are integrated by a capacitor and a potential which is indicative of the integrated signals is slowly developed at one capacitor terminal. A ramp capacitor is charged each half cycle of energizing potential. When the ramp capacitor potential crosses over the potential displayed at the one terminal of the integrating capacitor, a comparator means generates an output signal.

Abstract: A control circuit for starting and operating a gas discharge lamp comprising a variable frequency waveform generator coupled to the discharge lamp via a non-resonant coupling network that includes a reactance type ballast impedance. The lamp current is monitored to automatically vary the frequency of the variable frequency generator as a function of the lamp current so as to vary the reactance of the ballast impedance in a sense to regulate or limit the lamp current.

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

Abstract: A lead-type ballast apparatus for operating a HID high-pressure sodium lamp. The ballast apparatus includes an additional capacitor associated with the input portion thereof which provides a desirable power factor for the life of the lamp. Also disclosed is the addition of a supplemental winding to which the additional capacitor is connected that results in diminished operating losses for the ballast apparatus as the lamp ages.