Abstract: Method of contactless measurement of the conductivity of semiconductors, said method being implemented by: a first assembly comprising a signal emission/reception system —a second assembly comprising at least one semi-conducting target and an inductor element, —a third assembly, said method comprising at least the following steps: a) the first assembly emits a multifrequency signal, b) the second assembly reflects or transmits at least one part of the multifrequency signal emitted, c) the first assembly receives the reflected multifrequency signal reflected by the second assembly, d) the third assembly calculates the coefficient of reflection or of transmission of the emitted signal, e) the third assembly provides the conductivity of the semiconducting target.

Abstract: Method of contactless measurement of the conductivity of semiconductors, said method being implemented by: a first assembly comprising a signal emission/reception system —a second assembly comprising at least one semi-conducting target and an inductor element, —a third assembly, said method comprising at least the following steps: a) the first assembly emits a multifrequency signal, b) the second assembly reflects or transmits at least one part of the multifrequency signal emitted, c) the first assembly receives the reflected multifrequency signal reflected by the second assembly, d) the third assembly calculates the coefficient of reflection or of transmission of the emitted signal, e) the third assembly provides the conductivity of the semiconducting target.

Abstract: Apparatus for measuring the local electrical resistance of a surface, the apparatus comprising: a DC voltage source for applying a bias voltage (Vpol) to the sample (E) for characterizing; a measurement circuit (CM) capable of being connected to a conductive probe suitable for coming into contact with a surface (SE) of said sample in order to generate a signal (S) representative of a contact resistance between said conductive probe and said surface of the sample; and a control device (CMD) for controlling said measurement circuit; the apparatus being characterized in that said measurement circuit comprises: a measurement resistive two-terminal network (DM) presenting variable resistance and connected between said conductive probe and a ground of the circuit; and a calculation unit (UC) for generating said signal representative of a contact resistance between said conductive probe and said surface of the sample as a function of a voltage (Vs) across the terminals of said measurement resistive two-terminal n

Abstract: Apparatus for measuring the local electrical resistance of a surface, the apparatus comprising: a DC voltage source for applying a bias voltage (Vpol) to the sample (E) for characterizing; a measurement circuit (CM) capable of being connected to a conductive probe suitable for coming into contact with a surface (SE) of said sample in order to generate a signal (S) representative of a contact resistance between said conductive probe and said surface of the sample; and a control device (CMD) for controlling said measurement circuit; the apparatus being characterized in that said measurement circuit comprises: a measurement resistive two-terminal network (DM) presenting variable resistance and connected between said conductive probe and a ground of the circuit; and a calculation unit (UC) for generating said signal representative of a contact resistance between said conductive probe and said surface of the sample as a function of a voltage (Vs) across the terminals of said measurement resistive two-terminal n

Abstract: A method and device includes measuring a multiple-phase fluid flowing through a pipe. The inventive method includes the following steps in which: a fluid is illuminated using a first coaxial probe placed in contact with the liquid phase of the fluid, and a first electromagnetic wave is emitted at a high frequency. The admittance at the interface between the first probe and the fluid is measured, and the fractions of at least two constituents of the liquid phase are calculated in order to obtain the effective permittivity (?1) of the phase. The method also includes the following steps in which: the fluid is illuminated using a second coaxial probe and a second electromagnetic wave is emitted at a low frequency. The admittance at the interface between the second probe and the liquid is measured, and the thickness (e) of the liquid is measured. The aforementioned calculation is performed on the basis of the calculated effective permittivity (?1) and the admittance measured by the second probe.

Abstract: A preprocessing circuit receives signals representative of a current circulating in a primary winding and of a current circulating in a secondary winding of a transformer. The signals representative of currents are used to calculate the values of a through current and a differential current. The preprocessing circuit performs a spectral analysis and provides a neural network with signals representative of the fundamental component of the through current, of the fundamental component of the differential current, of the second harmonic and of the fifth harmonic of the differential current. The neural network identifies fault conditions and normal operation states, and supplies a triggering and/or alarm signal to an output when a fault condition is detected.

Abstract: The monitoring device comprises a measuring channel of the ground fault voltage, a measuring channel of the ground fault current, and a digital processing circuit whose role is to search for and indicate the presence of a ground fault. The processing circuit determines the fundamental parts of the ground fault current and voltage to compute the phase difference .phi. between the two parts and the cos .phi. value. The evolution of this phase difference is representative of a fault.

Abstract: A pseudo-random measuring signal whose spectrum is constituted by lines of predetermined frequencies spaced apart from each other is applied to a system to be characterized, and one or, successively and one by one, a plurality of lines of the spectrum of the measuring signal are selected for making a comparison in phase and amplitude between the input and the output of the system; for a non-linear system, one or, successively and one by one, a plurality of lines of the spectrum of the measuring signal are eliminated at the input of the system, and the phase and/or amplitude of the corresponding line is measured at the output of the system.