Abstract: A method and a device for the master-slave control of the power of a multiphase thyristor bridge. A master-pulse, from a master-pulse generating circuit coupled with one phase of the multiphase means, is applied to a slave-pulse generating circuit. Three slave-pulses out of phase of 120.degree. with respect to one another are produced by a slave-pulse generating circuit in case of a three-phase means. Said slave-pulses are applied across the gates and the anodes of a multiphase thyristor bridge.

Abstract: The present invention relates to photosensitive device comprising a plurality of superposed semiconductive layers, wherein grooves are hollowed on the face exposed to the irradiance in order to reach and to pass through the junctions upon which the operation of the device is dependent and filled with a passivating agent transparent to the incoming light, the improvement being that the sizes of the grooves are selected in order to obtain a maximum efficient volume exposed to the irradiance close to the junctions upon which the operation of the device is dependent and to minimize the the cross-section of the junction.The present invention permits to obtained more efficient photothyristors and phototriacs.

Abstract: This invention relates to a synchronous device for a static relay by a high frequency signal.According to this invention, a high frequency alternating signal source is serially connected with a diode between the anode a and the gate g of a thyristor, the main terminals a and b of which are connected to the terminals of a charge and supply circuit. The thyristor can be triggered only when the voltage between these terminals is lower than a threshold value and control signal is provided for high frequency source. The invention also provides for high frequency synchronous control methods for bidirectional devices.The invention is applicable to a very simple and cheap control system of static relays.