Abstract: The operation of the starting circuit is only allowed for a predetermined time period in response to a control signal which is generated either following the application of the alternating voltage to the input terminals of the lamp circuit at the beginning of a working period of the lighting installation including said lamp, or a predetermined delay after interruption of said alternating voltage due to a short power interruption. The operation of the starting circuit is not allowed if the lamp extinguishes due to an increase of its voltage, thus avoiding attempts to re-start a defective lamp.

Abstract: In a lighting installation comprising light sources each connected to an A.C. supply system, a control device including: power variation circuits connected to the different sources and each comprising means for varying the electrical power supplied to the respective source, in response to magnitude variations of an electrical quantity, and control circuits associated to the different sources and each comprising a clock circuit, an illuminating programme circuit in which is recorded a programme representing desired timed variations of the illuminating power for a given period, a selection circuit receiving clock pulses from the clock circuit and connected to the programme circuit for selecting an illuminating power dependent on the elapsed time from the beginning of said period, and an output circuit for converting said selected power to a particular magnitude of said electrical quantity.