Abstract: A optical relay which includes a target plate which is made of an electrically insulating material and allows light to pass in a manner depending on the electric field parallel to the direction of propagation of this light, wherein a first side of this target plate is scanned by an electron beam produced by an electron gun, an anode in the form of a grid, a thin plate which is optically transparent and electrically conducting, an amplifier applying the video information of the video signal to the relay. The optical relay includes means by circuit elements which it is is capable of writing and erasing the target plate in the charge accumulation mode cooperating with a precursor eraser acting on a limited number q of scanning lines positioned beyond the line n to which the write operation relates. In order to transmit the picture in accordance with a television standard, a de-interlacing arrangement is used.

Abstract: A device for detecting specific positions of a moving part, for example a rapidly rotating part provided with soft-magnetic projecting elements which alternately pass close to the detector device, which comprises a stationary magnetic exciter circuit for a Hall-effect crystal.The magnetic exciter circuit comprises a single permanent magnet having one pole face oriented towards the moving part, and provided with two symmetrical soft-magnetic pole pieces forming a narrow gap in which the Hall-effect crystal is disposed.

Abstract: Flasher unit which comprises an electromagnetic relay which is controlled by an astable multivibrator.The voltage drop across a resistor of low value controls a circuit for inhibiting the operation of the astable multivibrator in the event of excess currents (short-circuit) or causes a frequency variation of the multivibrator in the event of too small a current (burnt-out lamp).

Abstract: A device for determining the angular position of a rotating part includes first and second parallel arranged magnets forming a symmetric magnetic excitation circuit with a Hall-effect element disposed on the axis thereof. The rotating part has first and second elements made of a soft magnetic material which are angularly displaced so as to alternately pass by the first and second magnets, respectively, to produce first and second oppositely directed transverse magnetic field components, H, at the Hall-effect element which thereby generates a signal whose polarity reverses to indicate angular position of the rotating part.