Abstract: A power amplifier circuit that has an inductor and capacitor connected to one end of the output winding of an RF transformer. The other end of the output winding is connected to a resistor that in turn is connected to ground. The transformer has two primary windings. Both primary windings have one end connected to a variable DC voltage supply. The other end of each primary winding is attached to a switch, such as a MOSFET. All three windings are wound around a core. Current flowing from the DC voltage supply to the switches causes a magnetic flux in the core. A voltage is generated on the secondary winding resistor. This voltage is fed back to the switches, controlling on and off timing. In this way the need to measure and record natural frequency is eliminated.

Abstract: This invention relates to a corona discharge ignitor used to ignite air/fuel mixtures in automotive applications and the like. To suppress an arc from forming when a voltage is applied to the ignitor, the corona discharge ignitor has various shapes and configurations, such as angular depressions or grooves, at the tip of the insulator. The shape and configuration of the tip provides a smaller radius which creates a more intensified electric field and provides better combustion.

Abstract: A density and viscosity sensor 1 for measuring density and viscosity of fluid F, the sensor 1 comprising: a resonating element 3, 3A, 3B, 3C, 3D, 3E, 3F, 3G arranged to be immersed in the fluid F, an actuating/detecting element 4, 4A, 4B coupled to the resonating element, a connector 7 for coupling to the actuating/detecting element 4, 4A, 4B, a housing 2 defining a chamber 8A isolated from the fluid F, the housing 2 comprising an area of reduced thickness defining a membrane 9 separating the chamber 8A from the fluid F, the membrane 9 having a thickness enabling transfer of mechanical vibration between the actuating/detecting element 4, 4A, 4B and the resonating element 3, 3A, 3B, 3C, 3D, 3E, 3F, 3G, the actuating/detecting element 4, 4A, 4B is positioned within the chamber so as to be isolated from the fluid F and mechanically coupled to the membrane 9, the resonating element 3, 3A, 3B, 3C, 3D, 3E, 3F, 3G arranged to be immersed in the fluid F is mechanically coupled to the membrane 9, wherein the res

Abstract: A density and viscosity sensor 1 for measuring density and viscosity of fluid F, the sensor 1 comprising a resonating element 3, 3A, 3B, 3C, 3D arranged to be immersed in the fluid F, an actuating/detecting element 4A, 4B coupled to the resonating element, and a connector 7 for coupling to the actuating/detecting element 4A, 4B. The sensor 1 further comprises a housing 2 defining a chamber 8A isolated from the fluid F, the housing 2 comprising an area of reduced thickness defining a membrane 9 separating the chamber 8A from the fluid F. The actuating/detecting element 4A, 4B is positioned within the chamber so as to be isolated from the fluid F and mechanically coupled to the membrane 9. The resonating element 3, 3A, 3B, 3C, 3D arranged to be immersed in the fluid F is mechanically coupled to the membrane 9. The membrane 9 has a thickness enabling transfer of mechanical vibration between the actuating/detecting element 4A, 4B and the resonating element 3, 3A, 3B, 3C, 3D.

Abstract: A method of detecting and locating noise sources each emitting respective signals Sj with j=1 to M, detection being provided by a sound wave or vibration sensors each delivering a respective time-varying electrical signal si with i in the range 1 to N, wherein the method steps include: (a) taking the time-varying electrical signals delivered by the sensors, each signal si(t) delivered by a sensor being the sum of the signals Sj emitted by the noise sources; (b) amplifying and filtering the time-varying electrical signals as taken; (c) digitizing the electrical signals; (d) calculating a functional; and (e) minimizing the functional relative to the vectors nj for j=1 to M so as to determine the directions of vector nj of the noise sources.

Abstract: According to the invention, the method of detecting and locating sources of noise each emitting respective signals Sj with j=1 to M, detection being performed using sensors each delivering a respective time-varying electrical signal si with i varying from 1 to N, consists in taking the time-varying electrical signals delivered by the sensors, each signal si(t) delivered by a sensor being the sum of the signals Sj emitted by the noise sources, in amplifying and filtering the time-varying electrical signals as taken, in digitizing the electrical signals, in calculating the functional f ? ( n 1 , … ? ? , n j , … ? ? , n N ) = ? k ? 1 ? ? ? ? R k1 with coefficients Rkl being a function of the vectors nj giving the directions of the noise sources, and in minimizing the functional f in such a manner as to determine the directions nj of the noise sources.

Abstract: The invention relates to a method of detecting and locating noise sources each emitting respective signals Sj with j=1 to M, detection being provided by means of sound wave or vibration sensors each delivering a respective time-varying electrical signal si with i in the range 1 to N. According to the invention, the method consists: in taking the time-varying electrical signals delivered by the sensors, each signal si(t) delivered by a sensor being the sum of the signals Sj emitted by the noise sources; in amplifying and filtering the time-varying electrical signals as taken; in digitizing the electrical signals; in calculating a functional; and in minimizing the functional relative to the vectors nj for j=1 to M so as to determine the directions vector nj of the noise sources.

Abstract: The invention relates to a method of measuring pressure in which an evacuated capsule (1) containing a resonant element (5) is placed in the fluid whose pressure is to be measured, a vibration characteristic of the element is measured, and the pressure is deduced from said characteristic. A resonant element is used which, during measurement, is to be found in a stress state that is close to buckling. For this purpose, it is possible to use heater means for heating the element and servo-controlled so as to keep the frequency of vibration thereof constant. The resonant element can be made of silicon. The invention is particularly applicable to oil wells.

Abstract: The invention concerns a device for mechanically locking with respect to a support an electronic component soldered on a printed circuit card directly mounted on said support. The invention comprises a main wall designed to rest against a support wall and at least an elastic tab forming a U-shaped back loop relative to said main wall, said main wall and said elastic tab bearing matching means for maintaining said tab in a position wherein it is compressed towards said main wall, said matching means being capable of being disengaged relative to one another by the effect of a tool actuated by an operator, said elastic tab being then released to be urged against the component.

Abstract: A method for detecting vibrations generated by the running of a tire on a safety insert, wherein a vibration signal is measured within a given frequency band and the measurement thus made is processed to detect a mode of resonance generated by this running. The energy of the signal measured by a sensor in two frequency bands, one being narrow and the other being wide, which are centered on the same line of the mode of resonance, is determined. The ratio of these two energies is compared with a given warning threshold.

Abstract: The friction clutch comprises a cover (8) with a base (80), a pressure plate (3) with a front friction face (30) for co-operating with a clutch friction and, set between the pressure plate (3) and the base (80) of the cover (8), a diaphragm (2) with a peripheral part extended inward by fingers (23) to oppose at will, by means of a nose (11) of a clutch bearing (10), the action of said peripheral part (21), a booster elastic washer (7) acting on the fingers (23) of the diaphragm (2) in the declutching direction resting on the cover (8): the booster washer (7) is arranged between the cover (8) and the leading-edge piece or nose (11) such that it is adapted to operate on the fingers (23) of the diaphragm (2) via said leading-edge piece or nose (11).

Abstract: In an electric motor which includes an electronic control device and an armature within a closed motor casing, the electronic control device is arranged within the casing, in a position offset axially from but close to the armature. The motor includes a thermal screen which is interposed axially between the armature and the control device, and the screen includes means for dissipating heat outside the casing.

Abstract: A self-propelled vehicle alternator used both as a generator and as an electric motor for starting the engine of the vehicle. A coil-carrying rotor and a multiphase stator connected to a bridge of diodes and switches for rectifying and controlling the phases cooperate for selective operation as a generator or starting motor. A control unit for the switches recognizes a code signal transmitted by a code transmitter and controls the phases of the stator to cause the alternator to operate as an electric motor and start the engine only if it receives a code signal from the transmitter authorizing starting.

Abstract: A motor vehicle power steering system includes a hydraulic pump, an electric motor for driving the pump, and a control unit for controlling the electric motor. The control unit includes means for controlling the power supply voltage applied to the electric motor so that said voltage increases up to a maximum value when the load impedance decreases from its unloaded value, and is at a low value when said load impedance is in the vicinity of its unloaded value.

Abstract: A three-phase synchronous electric motor, especially a motor of a motorized fan unit for a motor vehicle, includes a synchronizing device in which the energizing signal for the three phases of the motor is synchronized with the rotational position of the rotor. The energizing signals are synchronized with a single position signal representing the rotational position of the rotor, and, in order to start the motor, its three phases are supplied with three energizing signals out of phase one with another by 2.pi./3; if the motor then fails to start, the energizing signals are phase shifted by 2.pi./3.

Abstract: A control device for a three-phase motor of a fan for a motor vehicle includes a current generator for the armature winding of the motor corresponding to each phase. Each current generator receives an input command signal such that the vector defined by the current intensities generated by the current generators is proportional to the vector V-ZI where V is a vector defined by the different voltages measured for the windings, I is a vector defined by the different currents measured for the windings, and Z is an operator corresponding to the impedance of the windings.

Abstract: A synchronous electrical machine comprising a rotor and a stator, each having a plurality of notches, wherein the rotor is a stack of laminations without conductor windings and without permanent magnets, and wherein the stator has magnetizing means defining at least one pair of poles thereon, while the notches of said stator receive at least one secondary winding.

Abstract: A circuit for measuring the duration of a cut-off period in the power supply to an electronic system, for example the control system of a motor vehicle starter, comprises a voltage splitting bridge and a processing unit receiving the output of the splitting bridge. The bridge supply voltage is derived from the power supply to the electronic system, and the bridge has a branch which includes a temperature variable resistor. The processing unit determines the duration of the cut-off period as a function of the value of the output voltage from the splitting bridge at the end of a cut-off period.

Abstract: Controlling an H-bridge of switches, characterized in that during a cycle, the current takes a peak value of constant sign during a continuous portion corresponding to a cycle fraction equal to .vertline.<V>/U.vertline., where <V> is the mean voltage applied to the load and U is the voltage of the DC voltage source, said portion being preceded by a cycle portion corresponding to a cycle fraction equal to 1/2(1-.vertline.<V>/U.vertline.) during which the two switches (I1, I2) of the H-bridge which are connected to ground are closed (or open as the case may be), and followed by a cycle portion likewise corresponding to a cycle fraction equal to 1/2(1-.vertline.<V>/U.vertline.) during which the two switches (I1, I2) of the H-bridge which are connected to ground are open (or closed as the case may be).

Abstract: A method of protecting an adjustable impedance element such as a transistor controlling the power supplied to an electric motor, in particular in a motor vehicle, wherein the control of said adjustable impedance element is modified when the current passing through it exceeds a given threshold, characterized in that said current threshold is an increasing function of the voltage U.sub.M across the terminals of the motor.