Abstract: A device for protecting track relays from electrical disturbances originating from a train's traction current. The device has: a control signal generator; a signal inverter, to invert periodically the polarity of the signal emitted; and a receiver for the control signal. A distinguishing circuit is provided downstream from the receiver for assessing the frequencies forming the receive signal and switching the track relay to the "line clear" position only after recognition of the frequencies forming the periodically inverted control signal.

Abstract: A coplanar patch antenna is formed, e.g as a printed circuit, on a dielectric support (1) by a metal patch (2) spaced from a coplanar ground plane (3) by a peripheral slot (4), and in the improvement is series fed by means of a slot line (5). The slot (4) can be made resonant by having a periphery of one wavelength or an odd multiple thereof, and a second slot line (7) can be fed into the slot (4) at a distance of one or an odd multiple of a quarter wavelength from the slot line (5) to provide an independent feed. The arrangement presents a feedpoint impedance of about 50 ohms at the ports (6,8) instead of about 400 ohms in prior arrangements.Balancing loads or 180 degree hybrid feeds to other quadrature ports (11,12) can be used to correct beam asymmetry due to the slot line feeders (5 and 7).

Abstract: An electric lamp has elongated metal foils as a part of the current conductor lead-throughs. Each metal foil has major surfaces which meet one another along each opposing side edge of the foil at an acute angle. The metal foil has a cross-section transverse to the side edges. At least one of the major surfaces has a pair of concave curvature portions each adjoining a respective side edge, and a convex curvature portion extending between the pair of concave curvature portions.

Abstract: An avalanche photo diode in which the guard ring portion and the front of the pn junction of the light receiving portion are formed at the same depth from the surface of an InP layer, so that the guard ring performs its desired function.

Abstract: The invention concerns ball bearings which automatically take up play, are self-centering and self-adaptable to the stress. The bearing comprises an inner ring (1), an outer ring in two parts (2a, 2b), balls (3), an elastically yieldable element (4) and a case (5). One of the rings is formed of two parts (2a, 2b) which are relatively movably fitted together and some of the four rolling raceways along which the balls roll have set-back depressions arranged along their circumference. Application in particular in the automobile industry.