A coupling circuit (20) with switching function for coupling an insulation monitoring device (6, 6a, 6b) to an unearthed power supply system (2, 2a, 2b), consisting of a coupling module (22) or a plurality of identical coupling modules (22) connected in series, wherein the coupling module (22) has at least one switch unit (25), which comprises a coupling impedance (26), a switch (24), arranged in series to the coupling impedance (26), for mains disconnection and a control circuit (28) for controlling the switch (24), and also exactly one transformer (30) for voltage supply and for potential separation.

The present disclosure relates to a device comprising an inductive element and a first capacitive element series connected between a first node and a second node, a first MOS transistor connected between the first node and a third node configured to receive a reference potential, the second node being coupled directly or via a second MOS transistor to the third node, a second capacitive element connected between a fourth node and an interconnection node between the first capacitive element and the inductive element, a current generator configured to provide an AC current to the fourth node, and a switch connected between the fourth node and the third node.

A system may include a resistive-inductive-capacitive sensor, a driver configured to drive the resistive-inductive-capacitive sensor with a plurality of driving signals, each driving signal of the plurality of driving signals having a respective driving frequency, and a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to measure a first value of a physical quantity associated with the resistive-inductive-capacitive sensor in response to a first driving signal of the plurality of driving signals, wherein the first driving signal has a first driving frequency; measure a second value of the physical quantity associated with the resistive-inductive-capacitive sensor in response to a second driving signal of the plurality of driving signals, wherein the second driving signal has a second driving frequency; measure a third value of the physical quantity associated with the resistive-inductive-capacitive sensor in response to the first driving signal; measure a fourth value of the physical quantity associated with the resistive-inductive-capacitive sensor in response to the second driving signal; determine a first difference between the third value and the first value; determine a second difference between the fourth value and the second value; and based on the first difference and the second difference, determine if a change in a resonant property of the resistive-inductive-capacitive sensor has occurred, and determine if a change in a quality factor of the resistive-inductive-capacitive sensor has occurred.

A device for measuring a microwave surface resistance of a dielectric conductor deposition interface includes: a test platform, a calibration component, a sealing cavity and a support plate; wherein the test platform comprises: a shielding cavity having an open bottom, a dielectric rod, an input coupling structure, an output coupling structure, and a dielectric supporter; the dielectric conductor test sample and the test platform form a TE.sub.0m(n+δ) mode dielectric resonator; the calibration component and the dielectric conductor test sample are mounted on the test platform to measure corresponding quality factors, thereby calculating the microwave surface resistance of the deposition interface of the dielectric conductor test sample. The present invention requires no pre-measurement of relative permittivity and loss tangent of the dielectric conductor test sample. After calibration, the microwave surface resistance of the dielectric conductor deposition interface can be obtained by only one non-destructive measurement.

A system may include a resistive-inductive-capacitive sensor, a driver configured to drive the resistive-inductive-capacitive sensor with a plurality of driving signals, each driving signal of the plurality of driving signals having a respective driving frequency, and a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to measure a first value of a physical quantity associated with the resistive-inductive-capacitive sensor in response to a first driving signal of the plurality of driving signals, wherein the first driving signal has a first driving frequency; measure a second value of the physical quantity associated with the resistive-inductive-capacitive sensor in response to a second driving signal of the plurality of driving signals, wherein the second driving signal has a second driving frequency; measure a third value of the physical quantity associated with the resistive-inductive-capacitive sensor in response to the first driving signal; measure a fourth value of the physical quantity associated with the resistive-inductive-capacitive sensor in response to the second driving signal; determine a first difference between the third value and the first value; determine a second difference between the fourth value and the second value; and based on the first difference and the second difference, determine if a change in a resonant property of the resistive-inductive-capacitive sensor has occurred, and determine if a change in a quality factor of the resistive-inductive-capacitive sensor has occurred.

It is described an attenuation measurement device (100), comprising:

i) a detector unit (110) having a coupling capacitance (120), and an input capacitance (130), wherein the detector unit (110) is configured to produce a detector output signal (112a,b) in reply to an input signal received at the coupling capacitance (120) and/or at the input capacitance (130);
ii) a test unit (140), coupled to the detector unit (110), and configured to provide a test signal (141) with at least one known signal property as a first input signal to the coupling capacitance (120);
iii) a calibration unit (150), coupled to the detector unit (110), and configured to provide a calibration signal (151) as a second input signal to the input capacitance (130); and
iv) a control unit configured to
a) determine a first detector output signal (112a) produced by the detector unit (110) in response to the test signal (141),
b) identify a specific calibration signal (151) that yields a second detector output signal (112b) that is comparable to the first detector output signal (112a), and
c) derive a capacitance-indicative information based on the identified specific calibration signal (151).

The present disclosure relates to a device comprising an inductive element and a first capacitive element series connected between a first node and a second node, a first MOS transistor connected between the first node and a third node configured to receive a reference potential, the second node being coupled directly or via a second MOS transistor to the third node, a second capacitive element connected between a fourth node and an interconnection node between the first capacitive element and the inductive element, a current generator configured to provide an AC current to the fourth node, and a switch connected between the fourth node and the third node.

A method and system of a method of measuring complex dielectric constant and permeability includes directing two polarizations onto a material under test and measuring one or more values of reflection coefficients. Further, the method includes integrating a p-wave reflection coefficient and a s-wave reflection coefficient and calculating, based on the measured one or more values of the reflection coefficients in association with a Brewster's angle, one or more of a complex dielectric constant and permeability.

A system for indicators of power meters.

A power converter having a switch network, a resonant tank network, and a controller performs in situ determination of the Q-factor of the resonant tank network. The controller excites transitory damped oscillations of the resonant tank network by applying a limited number of ON-pulses to the transistor switches of the switch network. The controller then samples the envelope of the waveform corresponding to the excited transitory damped oscillations and processes the resulting set of digital signal samples to determine the Q-factor of the resonant tank network. The Q-factor determination can be repeated to prevent the power converter from being operated under undesirable operating conditions caused by certain ambient factors, such as the unexpected presence of metal objects in the immediate vicinity of the power converter.