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

Abstract: A power supply apparatus for a fluorescent lamp comprises an inverter circuit for converting AC line power to a high-frequency drive voltage having a square waveform, this high-frequency drive voltage being applied to a fluorescent lamp through an inductor and a capacitor connected in series to form a series-resonance circuit which provides a ballast impedance after ignition of the fluorescent lamp has been achieved. A sufficiently high voltage to ensure reliable ignition of the fluorescent lamp is ensured by a ringing oscillation which is produced across another capacitor, connected across the lamp, when the fluorescent lamp is in the high-impedance state prior to ignition.

Abstract: A pulse network is connected to the inductive ballast of a fluorescent lamp dimmer and includes a discharge resistor in parallel with the pulse network capacitor. The resistor size is such that it will completely discharge the capacitor prior to the initiation of any phase delayed half wave voltage which is applied to the ballast.

Abstract: A pair of 48-inch long preheat fluorescent lamps, each one and a half inches diameter and consuming less than 10 watts power per foot of length, are connected in series with each other and with a ballast, for operation from 50 or 60 hertz a-c line voltage in the range of 200 to 300 volts. A starter switch is connected in parallel across each lamp. The lamp designs are specified such that they will start and operate in the circuit from the a-c line voltage.

Abstract: A discharge lamp ballast circuit comprises at least one discharge lamp connected in series circuit with a ballast capacitor and inductor across a pair of input terminals for a source of A.C. supply voltage. A controlled semiconductor switching element is coupled across the lamp electrodes and a control circuit for the switching element is coupled to the input terminals and to a control electrode of the switching element. A voltage dependent non-linear impedance device is connected in shunt with the capacitor so as to limit the capacitor voltage to a predetermined value. The voltage dependent impedance device prevents the occurrence of hazardous voltage levels in the circuit and improves the stability during the warm up phase.

Abstract: A fluorescent lamp ballast circuit comprising conductors for connection to an electrical power source, and an impedance such as a capacitor connected between one of the conductors and the power source. A positive temperature coefficient resistor may be provided in parallel with the aforesaid impedance.

Abstract: A circuit for suppressing interference pulses occurring in transformers with high leakage inductance. The circuit includes current controlled switches connected to the transformers having secondary windings. The switches are controlled by a trigger circuit and a control device. The interference pulses are suppressed by a pulse suppression circuit connected between the secondary windings of the transformers and the trigger circuit. Furthermore the transformers' secondary windings are interconnected in phase to the pulse suppression circuit. The correct interconnection is controlled and/or indicated.

Abstract: A lightweight starting and operating ballasting means for starting and operating a fluorescent lamp means from a household source of AC energy. The ballasting means has elements which perform with the lamp means in a starting mode and an operating mode. In the operating mode with a low-pressure mercury discharge existing between the lamp electrodes, the lamp means is ballasted solely by a series-connected resistor means and capacitor means.

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

Abstract: An electronic ballast-inverter for multiple fluorescent lamps employs a push-pull inverter and a series resonant circuit for driving the lamps. The inverter operates at the resonant frequency of the series resonant circuit. Current in the resonant circuit is limited, for low-load conditions, in response to a sensing voltage which is used to lower the frequency of operation of the inverter, to make the load more reactive.

Abstract: The invention relates to an electric arrangement comprising two series-arranged discharge tubes which are provided with preheatable electrodes and which are stabilized by means of a relatively small ballast. The tubes are shunted by a semi-conductor switching element which operates in the operating condition of the tubes.According to the invention a control circuit of the semi-conductor switching element includes a non-linear circuit element which ensures that the discharge tubes do not ignite before the electrodes are in the warm state.

Abstract: The invention relates to a power supply system for a semiconductor light source of which the power is regulated in the steady state by a regulating loop comprising an electronic switching circuit controlled by a signal characteristic of the power emitted by the laser which closes the regulating loop when the output power has reached, a threshold power, a ramp generator supplying a ramp of current to the laser solely from the instant when the feed voltage is established for reaching the threshold.

Abstract: Circuits are disclosed for use in a gaseous-discharge lamp lighting system which provide starting pulses to the lamp and/or a source of auxiliary light. One circuit provides starting pulses and/or auxiliary light until the gaseous-discharge lamp approaches its normal operating condition, while other circuits terminate these functions once the gaseous-discharge lamp ignites.

Abstract: Electrical lamp ballast system for starting and operating fluorescent lamps with improved efficiency. System includes high leakage reactance autotransformer having primary and secondary windings, and a ballast capacitor connected in series with the secondary winding and two serially connected fluorescent lamps of low starting and operating voltage, the secondary circuit being connected to a tap on the primary winding for reducing the ratio of the ballast power input to the lamp light output. The system provides for reduced lamp current crest factor, thereby improving life and operating characteristics of the lamps.

Abstract: Electrical lamp ballast system for starting and operating fluorescent lamps with improved efficiency and safety. System includes high leakage reactance autotransformer having primary and secondary windings, and a ballast capacitor connected in series with the secondary winding and two serially connected fluorescent lamps of low starting and operating voltage, the secondary circuit being connected to a tap on the primary winding for reducing the ratio of the ballast power input to the lamp light output. A starting capacitor connected across one of the lamps has a resistor of predetermined resistance connected in shunt therewith to reduce the peak voltage to ground resulting from removal of that lamp from the circuit, so that electrical shock hazard to service personnel is minimized.

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

Abstract: A fluorescent lamp fires more quickly at low temperature and its service life is lengthened if the input terminals of a full-wave rectifier are connected to the lamp electrodes and a resistor and capacitor are connected in parallel circuit between the output terminals of the rectifier. The voltage pulses applied to the electrodes prior to firing are reduced in peak amplitude and broadened by the improved circuit.

Abstract: A device which is designed to save electrical energy expended by a regular rapid start fluorescent lighting fixture having a plurality of lamps, or tubes, and a conventional ballast. The device comprises the combination of a step-up transformer, a resistor and two capacitors, all of which are mounted externally of the ballast. The device is wired in series with the ballast and one of the lamps to allow normal ballast voltages to be delivered to the lamp circuit, thereby eliminating any detrimental effects to the lamps or ballast. At the same time, the current to the lamps and consequent consumption of power by the lamps is substantially reduced to save electrical energy while providing a reduced, but uniform level of illumination.

Abstract: Circuits are disclosed for use in a gaseous-discharge lamp lighting system which provide starting pulses to the lamp and/or a source of auxiliary light. One circuit provides starting pulses and/or auxiliary light until the gaseous-discharge lamp approaches its normal operating condition, while other circuits terminate these functions once the gaseous-discharge lamp ignites.

Abstract: A synthesizer using the additive method of color synthesis and having a plurality of different color filters to provide corresponding primary color radiations which are combined to produce a tone having a specified color content. The filters are illuminated by either one or a plurality of gas discharge lamps equal in number to the number of color filters, the frequency and duration of the flashes from the lamp incident on each filter being determined by a control circuit to produce a predetermined luminous intensity for each primary color. The circuit may be programmed by specifying numerical values for the required luminous intensity of each primary color and the circuit adapted to control the frequency and duration of the flashes in accordance with the specified numerical values.

Abstract: A starting circuit for high intensity discharge lamps supplied from an alternating current line through a ballast inductance, and in some cases a pulse transformer inductance, includes a surge voltage protector (SVP) or like voltage responsive, current switching gas breakdown device connected intermediate the end of the inductance, a capacitor connected to the lamp end of the inductance, the SVP and capacitor being connected in parallel with each other and in series with a resistance across the lamp so that upon breakdown of the device in each half AC cycle the capacitor discharges applying a voltage surge to the lamp stepped up through the inductance. The charge on the capacitor follows the ignition voltage required to start or reignite the lamp as the ignition voltage varies during the life of the lamp.

Abstract: A circuit for switching storage capacitors in a high voltage xenon flash tube circuit includes at least one storage capacitor with parallel low and high resistance paths in series with the capacitor, switching means selecting one of the two paths and a time delay device triggering discharge of the tube at a predetermined interval, the discharge time constant of said one capacitor being a substantial portion of the triggering interval. The time delay device enables operation of the switching means a substantial time after triggering discharge.

Abstract: Electrical lamp ballast system for starting and operating fluorescent lamps with improved efficiency. System includes high leakage reactance autotransformer having primary and secondary windings, and a ballast capacitor connected in series with the secondary winding and two serially connected fluorescent lamps of low starting and operating voltage, the secondary circuit being connected to a tap on the primary winding for reducing the ratio of the ballast power input to the lamp light output. The system provides for reduced lamp current crest factor, thereby improving life and operating characteristics of the lamps.