Abstract: A device for quantified analog display, with planar structure, and measurement apparatus with multiple ranges and multiple operating modes using this display, which visualizes in analog form a value of a selected measured quantity among several. The display device comprises a flat substrate (2), a succession of identical electrodes (6) arranged side by side on one face of the substrate, and selectively excitable, and with at least one graduated scale (7) adjacent to the succession of identical electrodes (6) to determine the value of the measured quantity, in combination with at least one electrode of the succession of identical electrodes.

Abstract: A multi-wavelength light emitting and receiving apparatus for monitoring connections by optical fibers comprising a case, an emission section, a reception section, a keyboard for selecting operating modes and measurement scales, a display arrangement, a processing unit including a microprocessor connected to the emission section, the reception section, the keyboard and the display arrangement, and a feed. The emission and reception sections are mounted in a drawer provided with a connector that can be inserted into a complementary connector provided in the case, this latter containing the keyboard, the display arrangement, the processing unit, and the feed.

Abstract: A Hall-effect current clamp, in which the constant-current generator (13) supplying the Hall-effect cell (8) comprises an operational amplifier (15) which has an internal-voltage reference (17) and which pilots a transistor (Q1) mounted in emitter follower in series with the cell (8), such that the current which traverses it is on the order of 1 mA. At the output of the measurement amplifier (14) of the clamp, a dividing bridge (P1,R5) whose intermediate lead is connected to the inverting (-) input of the amplifier (14) permits obtaining a supplementary amplification of the output signal of the clamp at the price of a low current consumption. Thus, the total current consumption of the clamp is maintained at a very low level, thereby providing a considerable increase in the life span of the batteries (9) used to supply the clamp.

Abstract: A device is provided for generating an AC current ramp for checking the tripping current of the circuit-breaker, in which the current is regulated by a power transistor driven by the voltage available at the middle point of a potentiometric divider, this latter comprising a field effect transistor which is itself driven by a voltage depending on the voltage at the terminals of a capacitor charged by an auxiliary battery. It further comprises a constant current generator which is fed with current by the auxiliary battery for charging said capacitor and a comparator amplifier a first input of which is connected to said capacitor, a second input of which is connected to the junction point between a measuring resistor and said power transistor and the output of which is connected to the gate of said field effect transistor.

Abstract: The invention provides a measuring attachment connectible to a multimeter for measuring earth resistances, comprising a casing having a first group of terminals for a measurement signal and a second group of terminals for electrical connection of the attachment to a multimeter, and electric circuits housed in the casing and comprising generator means for generating an AC current of constant value but of a frequency different from that of the mains and its harmonics, said generator means having an output connected to first and second terminals of said first group of terminals, and a synchronous detector having a measurement signal input which is connected to said second terminal and to a third terminal of said first group of terminals, a control input which is connected to said generator means and an output which is connected to first and second terminals of said second group of terminals.

Abstract: A shock-proof case especially suited for portable measurement apparatus. The case is comprised of a moldable elastomeric material having a wall with an opening therein, in the periphery of which is formed an elastic encasement groove for receipt of a plate of a material significantly more rigid than said elastomeric material. The plate includes numerous cavities in its peripheral region encased within the groove. The elastomeric material of the case is remolded over the peripheral region of the plate in such a way that the elastomeric material fills the cavities in the plate during the molding process, and thus ensures an effective bonding between the plate and the elastomeric material of the case. The case may also be provided with damping means of varying thickness to cushion the apparatus against shock.

Abstract: A stake is provided in the form of a smooth cylindrical metal rod which has a point at its lower end and to which is welded a screw thread formed by a helical spring having a polygonal cross-section, preferably a square section, which is welded to the rod at a limited number of spaced-apart points, at least a part of the spring being thus free to move with respect to the rod. Preferably, only the lower end of the spring is welded to the rod. The stake is more especially, but not exclusively, usable for measuring the electrical resistances of ground connections.

Abstract: An electromagnetic relay comprising a base of insulating material carrying stationary and movable contacts and output lugs, and a motor assembly, the latter comprising a right-angled yoke, a core with its coil, crimped to the inner face of a first one of the two flanges of the right-angled yoke, and an armature pivotally mounted to the free end of the second flange of said yoke and having bent arms operable to actuate the movable contacts when the base is fixed to the outer face the second flange and the coil is energized. The coil has a spool or frame with at least one end flange provided with metal tongues for coil connection extending towards the base and passing through apertures in the second flange of the yoke, said tongues resiliently engaging inner ends of associated ones of said output lugs.

Abstract: A magnetic flywheel for a manually-driven magneto megohmmeter with step variable voltage comprising a rotor formed by a ring of magnetic material carrying permanent magnets, and a stator, disposed inwardly of the rotor and formed by an assembly of magnetic circuits each having a C-shape with a coil wound around the central portion thereof and with two pole surfaces at the ends. In order to reduce the starting torque, the number of pairs of permanent magnets is one less than the number of magnetic circuits, and the angular distance between the pole surfaces of one magnetic circuit is equal to the angular distance between two adjacent permanent magnets. Also, the arc length of each pole surface of a magnetic circuit is substantially equal to half the angular distance between two adjacent permanent magnets.

Abstract: Electromagnetic relay comprising resilient U-shaped tongues having each a pair of arms resiliently engaging fixed contact studs for electrically interconnecting them, and a movable control member adapted to move one of the arms of each tongue away from the corresponding contact stud, for breaking the electric connection. This relay further comprises a second control member movable in a direction opposite to that of the first control member and adapted to co-operate with the first control member for clamping the U-shaped tongue and move the two arms thereof away from the relevant contact studs.

Abstract: A magnetic circuit comprising a fixed core, yokes having flat portions in parallel planes, and an armature comprising a permanent magnet provided with pole pieces having end portions projecting on either side of the magnet, a flat portion of a first one of said yokes penetrating into the space between two end portions of the pole pieces located on one side of the magnet axis, the air gap surfaces of said yokes and of said pole pieces extending normally to the magnet axis and, one the other side thereof, at least one projecting end portion of said pole pieces penetrating between two flat portions of second and third yokes carried by a same free end of the core. Such a magnetic circuit is suitable for monostable or bistable operation in relays, contactors or solenoid valves.