Abstract: Electronic system for generating and controlling light effects on projectors utilizing arc lamps, composed of an electronic power unit provided with a transformer fed via transistors, the secondary circuit of the transformer being connected to the feed terminals of the lamp, within the secondary circuit of the transformer there being connected a component for withdrawing a proportion of the instantaneous current circulating through the secondary circuit to produce an electrical signal which is made available to a control block which also receives an electrical reference signal generated by a pulse generator, the control block being arranged to compare the two electrical signals and to set the transistors to a conducting or inhibiting state depending on the result of the comparison, the amplitude and frequency of the electrical reference signal being adjustable by the operator.

Abstract: A light beam projector device having a light source and a reflector arranged to direct the light originating from the light source in such a manner as to form a light beam, said reflector having a curved concave reflecting surface with a geometrical focus where the light source is positioned, at least a first tubular wall made of a material able to filter color from the light and arranged when set in an active position to laterally embrace the light source so as to be traversed by the light before it reaches the reflector, the tubular wall being arranged with its axis substantially coinciding with the axis of the reflector, actuator means for axially moving the tubular wall into an active position or to an inactive position below the reflector where it does not interfere with the radiation emitted by the light source and directed towards the reflector, and to intermediate positions in which only a part of the tubular wall is traversed by the light, and a second tubular wall or tubular wall segment positioned