Abstract: In order further to develop a built-in light comprising a frame 1 which can be mounted to a ceiling, a retaining hoop 2 which can be fixed to the top side of the frame, a reflector 4 which can be connected to the frame 1 and a fitting carrier 3 which can also be connected to the frame 1 in such a way that it can be more easily assembled, it is proposed that the retaining hoop 2 is provided with lateral guide surfaces 2d for guiding the fitting carrier 3 and support surfaces 2e engaging thereunder for draw-like receiving the fitting carrier 3 and that there are provided latching means for connecting the fitting carrier 3 to the retaining hoop 2.

Abstract: Described is a lamp which includes two fluorescent tubes arranged in parallel relationship and light distribution chambers which extend laterally therefrom on both sides, and a light-technical louver element arranged beneath the fluorescent tubes, for delimiting the light radiating angle of the fluorescent tubes downwardly, wherein arranged between the fluorescent tubes is an elongate trough which is in the form of a mirror on its outside, for accommodating the electronic operating elements for the fluorescent tubes (FIG. 1).

Abstract: The invention concerns a cable suspension arrangement for hanging luminaries including a holder for a cable which is vertical in the position of installation for suspending a luminaire at a cable holder point and a fixing region for fixing the luminaire to the suspension arrangement, wherein the fixing region has a center, wherein there is provided a mechanism for displacement of the cable holder point laterally with respect to the longitudinal direction in which the cable extends, relative to the center of the fixing region for the luminaire, or for displacement of the center of gravity of the luminaire, laterally with respect to the longitudinal extent of an associated luminaire, relative to the cable holder point of the luminaire housing.

Abstract: The invention, which relates to a method for generating a starting voltage for a fluorescent lamp, in which the starting voltage is generated by means of alternating voltage that is impressed on an LC series resonant circuit, and to a corresponding circuit arrangement, is based on the object of increasing the reliability of starting and avoiding maximum permissible starting voltages being exceeded. According to the invention, this object is solved in that the frequency of the alternating-voltage generator can be controlled by a control unit and in that a measuring circuit is connected to the control unit, whereby the alternating voltage can be gradually reduced from a high frequency to a lower frequency, where the lamp voltage is compared to a setpoint value at certain intervals and the starting procedure terminated when the setpoint value is reached.

Abstract: The invention relates to a method and ballast for operating a lamp (3) fitted with a fluorescent tube (2), whereby the operating data of certain recognizable lamp types (T1, T2, Tn−1, Tn), at least the lamp voltage (UL), lamp current (IL) and preheating currents (Ivorh1, Ivorh2, Ivorhn−1, Ivorhn) is stored in a register (R) for the heating of the electrodes.

Abstract: A d.c. voltage supply circuit including a flyback converter having an inductor which is alternatingly charged through an electronic switch and discharged via a diode onto a capacitor. The output voltage of the flyback converter is continuously monitored. If a threshold value is exceeded, the electronic switch, which is mounted in an input line of the flyback converter, is changed into the off-state. The off-state of the electronic switch is terminated as soon as the output voltage has again fallen below the threshold value. Loads requiring a specific d.c. voltage may be connected to different supply voltages without the need of changeovers. The circuit offers a high security in view of overvoltage from the power network. It is self-monitoring and protects the connected load.

Abstract: A d.c. supply circuit containing a series-circuit composed of a switch and an inductor. A regulator circuit is provided to alternatingly drive the switch into conductive and nonconductive states. The control is performed by the inductor and responsive to current (i.sub.L).The series-circuit also includes an auxiliary switch, to which is connected, in parallel, a series-circuit formed by a diode and a capacitor. In short periods, in which the switch is conductive while the auxiliary switch is nonconductive, the capacitor is charged in order to generate the supply voltage for the regulator circuit.

Abstract: An elongated luminaire is provided having at least one fluorescent lamp and a louver arranged therebelow. The louver consists of lamp-parallel longitudinal reflectors and reflecting cross-oriented lamellae arranged transversely thereto and subsequently of V-shape in cross section. The lamella legs have a parabolic shape in cross section. A light guiding plate is provided extending from one leg of each cross-oriented lamella, extending diagonally upwardly towards and almost adjacent to the lamp. Each light guiding plate substantially overlaps the interspace between neighboring cross-oriented lamella in the vertical projection. Thus, the entire light flux, emerging downwards, is directed, depending on the position of the cross-oriented lamellae and of the light guiding plates, in the desired direction into the lower hemisphere so that it is possible to obtain different light distribution curves of symmetrical or asymmetrical shape with characteristic preferred directions.