A test apparatus (1) for test cards (37), comprising a receiving device (3) for holding at least one test card (37) to be tested, comprising at least one contact device (4) for making electrical touch contact with electrically conductive contact points of the at least one test card (37) in the receiving device (3), wherein the contact device (4) can be arranged vertically above the receiving device for the purpose of making touch contact, and comprising an actuating device (19), which is formed to displace the contact device (4) and the receiving device (3) relative to one another for the purpose of establishing the touch contact. It is provided that the receiving device (3) can be displaced by means of the actuating device (19) from a test position, which is located vertically below the contact device (4), into a loading and unloading position, which is laterally spaced apart from the contact device (4), and the other way round.

An LCR meter to increase accuracy of balancing uses sub-balancing method, additional to analog balancing by trans-impedance amplifier (TIA). For this, the LCR meter, based on TIA, to correct analog auto-balancing, applies the inverted voltage equal to unbalanced voltage to noninverting input of the TIA. And only one measurement of voltages is needed for.

A magnetic sensor circuit includes a plurality of magnetic sensors having bias input and bias output terminals and first and second measurement terminals. The circuit includes a diagnostic sensor having bias input and bias output terminals and first and second measurement terminals. The circuit includes a first multiplexer configured to selectively couple a current source to the bias input terminals of the magnetic sensors or to the bias input terminal of the diagnostic sensor and includes a second multiplexer configured to selectively couple the bias output terminals of the magnetic sensors or the bias output terminal of the diagnostic sensor to a first terminal of a switch. The circuit includes a third multiplexer configured to selectively couple the measurement terminals of the magnetic sensors or the measurement terminals of the diagnostic sensor to differential input terminals of an amplifier.

A magnetic sensor circuit includes a plurality of magnetic sensors having bias input and bias output terminals and first and second measurement terminals. The circuit includes a diagnostic sensor having bias input and bias output terminals and first and second measurement terminals. The circuit includes a first multiplexer configured to selectively couple a current source to the bias input terminals of the magnetic sensors or to the bias input terminal of the diagnostic sensor and includes a second multiplexer configured to selectively couple the bias output terminals of the magnetic sensors or the bias output terminal of the diagnostic sensor to a first terminal of a switch. The circuit includes a third multiplexer configured to selectively couple the measurement terminals of the magnetic sensors or the measurement terminals of the diagnostic sensor to differential input terminals of an amplifier.

A method of sensing electrical power being provided to a structure using a sensing device, a calibration device, and one or more processing modules. The sensing device can include one or more magnetic field sensors. The sensing device can be attached to a panel of a circuit breaker box. The panel of the circuit breaker box can overlie at least a part of one or more main electrical power supply lines for an electrical power infrastructure of a structure. The calibration device can include a load unit. The calibration device can be electrically coupled to the electrical power infrastructure of the structure. The method can include automatically calibrating the sensing device by determining a first transfer function in a piecewise manner based on a plurality of ordinary power consumption changes in the structure. The method also can include determining a power consumption measurement using the one or more processing modules based on one or more output signals of the sensing device and the first transfer function. Other embodiments are provided.

A method of sensing electrical power being provided to a structure using a sensing device, a calibration device, and one or more processing modules. The sensing device can include one or more magnetic field sensors. The sensing device can be attached to a panel of a circuit breaker box. The panel of the circuit breaker box can overlie at least a part of one or more main electrical power supply lines for an electrical power infrastructure of a structure. The calibration device can include a load unit. The calibration device can be electrically coupled to the electrical power infrastructure of the structure. The method can include automatically calibrating the sensing device by determining a first transfer function in a piecewise manner based on a plurality of ordinary power consumption changes in the structure. The method also can include determining a power consumption measurement using the one or more processing modules based on one or more output signals of the sensing device and the first transfer function. Other embodiments are provided.

A system and method for calibrating rigid and non-rigid arrays of 3-axis magnetometers as disclosed. Such arrays might be used to analyze structures containing ferromagnetic material. The calibration determines scale factor and bias parameters of each magnetometer in the array, and the relative orientation and position of each magnetometer in the array. Once the parameters are determined, the actual magnetic field value at the magnetometer location can be simply related to magnetometer measurements. The method and system can be used to calibrate an array of 3-axis magnetometers in aggregate as opposed to individual magnetometers. This is critical in large arrays to increasing reproducibility of the calibration procedure and decreasing time required to complete calibration procedure.

The present application relates to a method for providing a corrected measuring signal indicating a high voltage on a high-voltage node (HV), including: injecting a periodic injection signal into a voltage divider coupled between the high-voltage node (HV) and a reference potential; obtaining a sensing signal at a sensing node (S) of the voltage divider, wherein the sensing signal depends on the periodic injection signal; from the sensing signal, separating a first sensing signal portion resulting from the high voltage and a second sensing signal portion resulting from the periodic injection signal; and depending on the second sensing signal portion, correcting the first sensing signal portion corresponding to the high-voltage signal in order to obtain the corrected measuring signal.

A system includes a monitoring and/or protection system that includes an insulation derivation circuit. The insulation derivation circuit is configured to derive a first temperature compensation curve based on a first temperature and a first current, and the monitoring and/or protection system is configured to communicatively couple to a first current sensor configured to sense the first current traversing a first phase of a stator winding of a motor, a generator, or a combination thereof. The insulation derivation circuit is also configured to communicatively couple to a first temperature sensor configured to sense the first temperature of the stator when the stator is energized, and the temperature compensation curve is configured to map a temperature to a leakage dissipation factor.

A system includes a monitoring and/or protection system that includes an insulation derivation circuit. The insulation derivation circuit is configured to derive a first temperature compensation curve based on a first temperature and a first current, and the monitoring and/or protection system is configured to communicatively couple to a first current sensor configured to sense the first current traversing a first phase of a stator winding of a motor, a generator, or a combination thereof. The insulation derivation circuit is also configured to communicatively couple to a first temperature sensor configured to sense the first temperature of the stator when the stator is energized, and the temperature compensation curve is configured to map a temperature to a leakage dissipation factor.