Abstract: A LED illuminator or an equivalent illuminator with a semiconductor light source for a headgear or equivalent, said illuminator comprising one or more light emitting semiconductor light sources (4), especially LEDs (Light Emitting Diode), a frame (1, 2, 11, 12), an electronics control part (5) for controlling the semiconductor light sources, and fastening parts for fastening the illuminator, wherein the semiconductor light sources are directed in at least one given direction, such as towards a working object and/or area, said illuminator being a unitary illuminator module, wherein the semiconductor light sources are fitted in a common, preferably rectangular connection part (3), side by side and directed towards the working object and/or area, and the frame consists of two frame parts (1, 2, 11, 12) folded one over the other, which can be attached to the headgear by means of releasable quick coupling parts, preferably snap-on bayonet catches.

Abstract: A LED illuminator or an equivalent illuminator with a semiconductor light source for a headgear or equivalent, said illuminator comprising one or more light emitting semiconductor light sources (4), especially LEDs (Light Emitting Diode), a frame (1, 2, 11, 12), an electronics control part (5) for controlling the semiconductor light sources, and fastening parts for fastening the illuminator, wherein the semiconductor light sources are directed in at least one given direction, such as towards a working object and/or area, said illuminator being a unitary illuminator module, wherein the semiconductor light sources are fitted in a common, preferably rectangular connection part (3), side by side and directed towards the working object and/or area, and the frame consists of two frame parts (1, 2, 11, 12) folded one over the other, which can be attached to the headgear by means of releasable quick coupling parts, preferably snap-on bayonet catches.

Abstract: A procedure and an apparatus for producing an a.c. voltage, in which procedure the a.c. voltage (u.sub.o) is produced via inversion from a d.c. voltage (U.sub.A). The d.c. voltage (U.sub.A) is produced by a generator (4). Moreover, the d.c. voltage (U.sub.A) is measured and stabilized. The frequency of the a.c. voltage is determined by means of an oscillator (9).