Abstract: A circuit arrangement for a high-pressure discharge lamp, having a main combustion chamber with first and second main electrodes and an auxiliary combustion chamber including: an inverter having first and second electronic switches and first and second output terminals; a drive circuit for the electronic switches; and an auxiliary starting circuit. The auxiliary starting circuit has input terminals coupled to the output terminals of the inverter; a first output terminal for the first main electrode; a second output terminal for the second main electrode; and an auxiliary electrode arranged on the side of the first output terminal for inducing an auxiliary starting voltage in the auxiliary combustion chamber. The auxiliary starting circuit includes a cascade circuit formed by the auxiliary electrode and the second output terminal of the auxiliary starting circuit, which provides a voltage for starting the high-pressure discharge lamp.

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

Abstract: An impedance matching circuit for a self-oscillating electrodeless fluorescent lamp ballast of the type having an inductor connected in series with the parallel combination of a capacitor and the lamp's drive coil includes an additional capacitor connected in series with the drive coil. The capacitance value chosen for the additional capacitor is dependent on: stresses on the parallel capacitor; matching the impedance of the ballast; and the impact of the capacitor on the loaded coil phase angle. The additional capacitor reduces the phase angle presented to the ballast, thereby lowering the sensitivity of the ballast to component and lamp variations. In addition, the overall impedance of the network is reduced, such that the required inductance of the series inductor is reduced; hence, the inductor can have fewer turns and lower conduction losses.

Abstract: A fluorescent lamp has an envelope tube forming a gas-tight enclosure about a pair of externally-energizable filaments which generate a plasma discharge for conversion to visible light; a keep-alive electrode is located adjacent to at least one filament. A dimming control circuit individually externally energizes each keep-alive electrode to generate an auxiliary discharge, between that keep-alive electrode and the adjacent filament, at a magnitude sufficient to maintain the adjacent filament in the spot mode of operation even if the main plasma discharge current is varied over a range sufficient to change the visible light output of the lamp over at least a 10:1 range.

Abstract: A metal halide high-intensity discharge lamp for connection to a constant wattage-type mercury ballast including a transformer having a secondary winding having a capacitor in series circuit arrangement therewith. The lamp includes starting aid means and warm-up assistance means to ensure reliable operation. The starting aid means is a voltage doubler comprising a diode and two resistors operating in conjunction with the ballast capacitor and also including a normally closed heat-responsive switch means operative to prevent voltage stress on the diode after the lamp starts.

Abstract: A metal halide high-intensity discharge lamp for connection to a constant wattage-type ballast including a transformer with a secondary having a capacitor connected in series circuit arrangement therewith. The lamp includes starting aid means including a voltage doubler comprising a diode and two resistors operating in conjunction with the ballast capacitor. The starting aid means further comprises a normally closed heat-responsive switch means operative to prevent voltage stress on the diode after the lamp starts.

Abstract: An RLC triggering circuit employs an inductance coupled to the trigger electrode of a triggered vacuum gap device. A capacitance and a switch are coupled in series with the inductance. A diode in parallel with the series-coupled capacitance and switch serves to provide a long, unidirectional current pulse to prevent the triggered vacuum gap from chopping current and generating dangerous surge voltages.

Abstract: A metal vapor discharge lamp includes a discharge tube with main electrodes at each end. A starting electrode extends around at least an axial portion of the tube intermediate the main electrodes, one main electrode is connected to the starting electrode by a first resistance and the other main electrode is connected to the other electrode by a second resistance. At least one of the resistances has a temperature dependent characteristic which is substantially more positive than the other resistance.

Abstract: A jacketed high pressure metal vapor discharge lamp comprising an arc tube having main electrodes at opposite ends and a starter electrode, has a resistor and a diode in series bridged across the main electrodes which are connected across a peaked lead ballast in operation. A second resistor connects the starting electrode to the remote main electrode. The circuit lowers the minimum open circuit voltage required from the ballast for reliable starting.

Abstract: The invention relates to a starting and operating device, including an intance in the ignition circuit, for a high pressure discharge lamp, especially for a high pressure mercury vapor discharge lamp with metal halide additive, having at least one starting electrode positioned near one of the main electrodes within the discharge vessel. The starting electrode and the main electrode remote from the starting electrode are bridged by an electric circuit externally of the discharge vessel which comprises a current-interrupting and/or current-limiting electrical component. This arrangement of an auxiliary electrode within the discharge vessel of a high pressure discharge lamp brings about a reduction of the supply voltage required for initiation of the discharge which is particularly desirous in the case of high pressure mercury vapor discharge lamps containing metal halides.

Abstract: The invention relates to a sunlamp device which is provided with a high pressure mercury vapour discharge tube and with an auxiliary device for extinguishing the discharge tube with a given time delay on termination of the desired irradiation period.According to the invention a switch connected in series with the discharge tube is shunted by a resistor having a positive temperature coefficient of resistance (PTC resistor). This ensures that after the switch has been opened on termination of the desired irradiation period the PTC resistor passes current for some time. As a result the resistance of this PTC resistor is increased, which causes the current through the discharge tube to be reduced. This finally results in an increase of the operating voltage of the discharge tube to a value higher than the available voltage, so that the tube is extinguished. This device is simpler than a known device provided with two timers.