Abstract: A control circuit which includes a circuit for regulating the time taken to desaturate the switching transistor. This regulating circuit is arranged to control the time for which the transistor is conductive, so that the desaturation time of the transistor is substantially nil when the rate of rotation of the engine is greater than a predetermined value.

Abstract: A strain gauge sensor for sensing stresses and deformations in mechanical members or structures, comprising a support substrate in form of a thin plate, made of an electrically-insulating material, preferably ceramic material, bearing on one face at least one thick-film resistor; said support substrate being adapted to be firmly attached with its other face onto a member or structure of which stresses and deformations are to be locally sensed, so that said stresses or deformations determine through the substrate corresponding deformations of said at least one thick-film resistor.

Abstract: The sensor includes a rigid support and a diaphragm having a peripheral portion fixed by a layer of glue to the support. The central portion of the diaphragm is spaced from the support and, on its surface facing the support, carries at least one thick-film resistor acting as a piezo-resistive transducer. The diaphragm can deform resiliently towards the support when a pressure is exerted on its other surface. The surface of the support which is connected to the diaphragm is flat, and the layer of glue has a calibrated thickness such that the distance between the diaphragm and the surface of the support at rest is substantially equal to the deflection of the diaphragm corresponding to a predetermined maximum pressure measured.

Abstract: In a thick-film pressure sensor comprising a support plate on at least one surface of which are deposited at least one thick-film resistor acting as a piezo-resistive transducer and at least one pair of thick-film conductors acting as rheophores, the at least one thick-film resistor and the thick-film conductors are covered with a protective layer of dielectric material.

Abstract: A method for achieving mechanical and electrical interconnection of first and second bodies of which the first has at least one conductive element its surface intended to face the second and the second has a through-hole for electrical connection provided with a metallic coating intended for electrical connections to the conductive element of the first body includes applying layers of vitreous glue to corresponding surface portions of the first and second bodies. Moreover, a coating of conductive material in a vitreous matrix is deposited by the thick film technique on the surface of the second body intended to face the first, adjacent the through hole with the coating extending at least partly into the hole and electrically connected to the metallic coating of this hole. The bodies are then joined bring the respective layers of glue into contact with each other and the conductive coating of the second body into contact with the conductive element of the first.

Abstract: In order to reapply the fluid operating pressure to the braking members of the wheels after an anti-locking operation has been carried out, a pumping device is provided which are driven by the subatmospheric pressure (vacuum) existing in the inlet manifold of the engine. The application of the braking pressure is controlled by a valve which receives an opening command signal consisting of a train of pulses from a control device. At least one vacuum sensor is provided which generates a monitoring signal indicative of the level of vacuum present in the inlet manifold. The control device causes opening of the valve with a command signal whose average is inversely proportional to the level of the monitoring signal generated by the vacuum sensor.

Abstract: An electrical sensor device, particularly a pressure sensor device, comprises at least one pressure transducer, particularly a thick-film transducer, connected to a monitoring circuit arranged to output an electrical signal which is variable in dependence on the pressure, an interface circuit connected to the monitoring circuit and arranged, in response to the said signal, to present an output resistance which increases or decreases in accordance with a predetermined response curve, on increase in the pressure detected by the transducers.

Abstract: A pressure measuring device comprises a support casing having an aperture, a substrate mounted in the casing and deformable through the effect of a pressure to be measured introduced into the casing through the aperture, at least one electrical deformation sensor, preferably a thick-film resistor, applied to the substrate, circuit means housed in the casing and connected to the at least one electrical deformation sensor for outputting electrical signals indicative, according to a predetermined response curve, of the deformations of the substrate and hence of the pressure acting thereon, and manually-operable electrical adjustment means mounted in the casing and connected to the circuit means, for modifying predetermined characteristics of the response curve.

Abstract: In order to detect relative linear displacements between two members, the transducer includes a fixed part or stator connectible to one of the members and a movable part or rotor rotatably supported by the fixed part. A flexible traction member has one end anchored to the other member and its other end connected to the rotor in such a way as to cause rotation of the latter in one sense relative to the stator when the members move away from each other. The transducer also includes a return spring which tends to rotate the rotor in the opposite sense of rotation when the two members move towards each other. Electrical sensor means output electrical signals indicative of the angular position of the rotor relative to the stator and hence of the relative position of the two members.

Abstract: An electronic ignition system, for a four-stroke, four-cylinder engine, having:sensors that provide signals indicative of the running conditions of the engine,two ignition transformers, each having their respective output windings connected to the spark plugs of a respective pair of cylinders of the engine,means for monitoring the current flow in the respective input windings of the two transformers,switching means for selectively and alternately connecting output of a single integrated circuit to the input windings of the two transformers, and a micro-processor unit. The switching means has two electronically controlled switch devices, respectively in series with the input winding of the first and of the second ignition transformer, connected together in a current path in parallel.

Abstract: The sensor comprises a body formed by first and second elements of which at least one has a cavity, the elements being sealed together to form a chamber. The chamber contains an electrically-conductive liquid which fills it almost completely so as to form a bubble. At least one main electrode and at least one pair of auxiliary electrodes extend into the chamber through the body and are accessible on the exterior thereof, so that any variation in the inclination of the body relative to at least one predetermined direction causes a movement of the bubble and a corresponding variation in the electrical resistance measurable between each auxiliary electrode and the main electrode. The electrodes are constituted by strips of electrically-conductive material deposited by screen printing on at least one of the said elements by thick film deposition method.

Abstract: The device allows the monitoring and diagnosis of the functioning of a system for controlling the stopping and restarting of an internal combustion engine for motor vehicles, comprising a plurality of electrical sensors which output two-level signals indicative of the condition of members which control the running of the engine and/or of respective controlled parameters or ranges, and an electronic monitoring and control unit with a microprocessor, connected at its input to the sensors and at its output to actuators for causing the engine to stop and restart. The diagnostic device comprises an interrogation device for carrying out a succession of sequential cyclical scans of the outputs of at least some of the sensors, and for generating, at each scan, a serial signal comprising a plurality of two-level signal portions, each indicative of the level of signal produced at the output of the respective sensor.

Abstract: A device for monitoring the pressure of fluid in an electrically conductive duct, such as an injection duct of a diesel engine, includes at least one electrical pressure transducer connectible mechanically and electrically to the outer surface of the duct, and support means for keeping the transducer in connection with the duct. A rigid casing for surrounding and protecting the support means and the transducer is formed in two parts which are hinged together so as to clamp the transducer to the duct. This casing is constituted at least in part by an electrically conductive material and has an internal electrical connection with the output of the transducer, whereby signals output by the transducer in operation can be picked up directly by the casing.

Abstract: The alternator comprises an induction winding sub-divided into two half-windings (1, 2) each connected to the input terminals of a respective double half-wave rectifier circuit (3, 4). It further includes thyristors (14) each of which connects a terminal (A, B, C) of one half winding (1) to a non-homologous terminal (C',A',B') of the other half-winding (2) such that, when the thyristors (14) are triggered, the electromotive forces generated in the two said half-windings (1, 2) are added in phase with each other. When the speed of rotation of the engine of the motor vehicle is less than a predetermined value, the said thyristors (14) are triggered and hence the two half-windings (1, 2) are connected in series with each other. If the speed of rotation of the engine surpasses this predetermined value, the thyristors (14) are not triggered, and the two half-windings (1, 2) are connected in parallel with each other.

Abstract: In a system for recharging electric accumulators, including a polyphase alternator connected to a rectifier circuit, and a voltage regulator circuit connected to the rectifier circuit and the field winding of the alternator, there is connected a circuit for detecting and indicating faults and operating anomalies. This circuit includes a signal processor circuit which is connected to the armature winding of the alternator and is operable to provide an output test signal substantially proportional to the mean value of the signal appearing, in operation, at the actual or virtual star point of the phases of the armature winding of the alternator. Generator means provide first and second predetermined reference output signals. A comparison circuit activates alarm signalling means when the test signal falls below the first reference signal, and when the test signal exceeds the second reference signal.