Abstract: A method for making a lamp wattage available for operating at least one gas discharge lamp depending on a dimming signal which is input into a wattage factor correction circuit, having a switch element that is switched on clocked by a switch-on time, wherein the wattage factor correction circuit emits an intermediate circuit voltage which in turn is input into a converter that makes the lamp wattage available, comprising the steps of: in an operating phase in which the dimming signal has no phase leading edge and no phase trailing edge, the wattage factor correction circuit and the converter are regulated independently of each other using a separate regulating circuit in each case; and in an operating phase in which the dimming signal has a phase leading edge or a phase trailing edge, the two independent regulating circuits are coupled to each other via a higher-order third regulating circuit such that the lamp wattage of the converter is adjusted such that the switch-on time of the switch element in the watt

Abstract: For driving one or more gas discharge lamps (2) to conduct or to block at any time and at the same time, a rectangular high voltage is generated from a high DC voltage, an alternating voltage with respect to a reference voltage (V?) is generated from the rectangular voltage, the alternating voltage is supplied to first electrodes (4) of the lamps, second electrodes (6) of the lamps are selectively connected to the reference voltage, a current flowing through each lamp is stabilized (26), the alternating voltage is filtered to provide a filtered voltage, a property of the filtered voltage is measured to provide a control signal, the control signal is used to control the frequency of the rectangular voltage, and the filtering has a response characteristic which is substantially identical to a response characteristic provided by a lamp when conducting and means for said stabilizing of current flowing through the lamp.

Abstract: In a method of detecting arc discharge in a glow-discharge apparatus GD that has a high-frequency power source PS, a cutting pulse is output for time T1 to the high-frequency power source PS to stop a supply of power to the glow-discharge apparatus GD, when dVr/dt?dVf/dt increases over a first level, where Vf and Vr are a traveling-wave voltage and a reflected-wave voltage applied to the glow-discharge apparatus GD, respectively. Arc discharge is determined to have developed in the glow-discharge apparatus, when Vr/Vf increases to a second level or a higher level within a preset time To after the supply of power to the glow-discharge apparatus is stopped.

Abstract: Color properties of high pressure sodium vapor discharge lamps are improved by disclosed operating circuit for applying pulsed direct current to the lamp. The circuit comprises a direct current supply circuit, a transistor switch in series with the lamp and the primary of a transformer connected across the supply circuit, a diode in series with the secondary of the transformer connected across the supply circuit, and SCR switch connected across the secondary of the transformer, and a control circuit connected to the switches for applying DC pulses to the lamp at a predetermined repetition rate and duty cycle. The circuit produces pulse waveforms which provide substantial color improvement in the lamp and makes efficient use of the energy supplied from the power source.