The present invention discloses an AC impedance measurement circuit with a calibration function, which is characterized in that only one calibration impedance is needed, associated with a switch circuit. Based on the measurement results of the two calibration modes, an equivalent impedance of the switch circuit, circuit gain and phase offset can be calculated. Based on the above results, the equivalent impedance of the internal circuit is deducted from the measurement result of the measurement mode to accurately calculate an AC conductance and a phase of the AC conductance for impedance to be measured. In addition, by adjusting a phase difference between an input sine wave signal and a sampling clock signal, impedance of the same phase and impedance of the quadrature phase can be obtained, respectively, and the AC impedance and phase angle of the impedance to be measured can be calculated.

Provided is a current measuring device for measuring current, including a conductor (1) adapted to pass current therethrough, and a circuit board (31) with a wire, the wire being adapted to extract a voltage signal from the conductor, in which the circuit board is disposed upright with respect to the conductor.

The present invention discloses an AC impedance measurement circuit with a calibration function, which is characterized in that only one calibration impedance is needed, associated with a switch circuit. Based on the measurement results of the two calibration modes, an equivalent impedance of the switch circuit, circuit gain and phase offset can be calculated. Based on the above results, the equivalent impedance of the internal circuit is deducted from the measurement result of the measurement mode to accurately calculate an AC conductance and a phase of the AC conductance for impedance to be measured. In addition, by adjusting a phase difference between an input sine wave signal and a sampling clock signal, impedance of the same phase and impedance of the quadrature phase can be obtained, respectively, and the AC impedance and phase angle of the impedance to be measured can be calculated.

A power detector includes a detection circuit and a bias circuit. The detection circuit is used to receive an input signal and output a power indication signal. The bias circuit includes a first impedance unit, a second impedance unit and a transistor. The transistor includes a first terminal and a control terminal coupled to the first impedance unit, and a second terminal. The second impedance unit is coupled between the first terminal of the transistor and an output terminal of the bias circuit, or between the second terminal of the transistor and a second terminal of the bias circuit. The output terminal of the bias circuit is coupled to an input terminal of the detection circuit, and is used to output a bias signal.

A system for measuring an electrical quantity of a current circulating in an electrical device mounted on a mounting support, including an electrical power supply device, the device for measuring the current circulating in the device, the device for tapping the voltage at the terminals of the device, and the device for measuring this voltage, device for processing the measurement information, and device for communicating the measurement information to a receiver. This system includes a first main module, including the power supply device, the current and voltage measurement device, the processing device and the communication device, and a second auxiliary module, including the voltage tapping device and electrical connection device connecting with the main module, this connection making it possible to supply voltage to the main module and to measure the voltage recorded by the auxiliary module, the second module including electrical coupling device for connecting to the terminals of the device to be measured, these device being adapted to the configuration of these terminals.

A system for measuring an electrical quantity of a current circulating in an electrical device mounted on a mounting support, including an electrical power supply device, the device for measuring the current circulating in the device, the device for tapping the voltage at the terminals of the device, and the device for measuring this voltage, device for processing the measurement information, and device for communicating the measurement information to a receiver. This system includes a first main module, including the power supply device, the current and voltage measurement device, the processing device and the communication device, and a second auxiliary module, including the voltage tapping device and electrical connection device connecting with the main module, this connection making it possible to supply voltage to the main module and to measure the voltage recorded by the auxiliary module, the second module including electrical coupling device for connecting to the terminals of the device to be measured, these device being adapted to the configuration of these terminals.

An energy metering system includes a plurality of current sensors suitable to sense current levels in a respective power conductor and each of said plurality of current sensors providing a respective first signal indicating respective the current levels. The energy metering system includes a plurality of non-contact voltage sensors suitable to sense voltage levels in a respective power conductor and each of the plurality of non-contact voltage sensors providing a respective second signal indicating respective the voltage levels. The energy metering system includes a monitoring device that receives each of the respective first signals and receives each of the respective second signals, and the monitoring device provides an indication of whether a circuit breaker has tripped based upon a respective first signal corresponding with one of the power conductors and whether the second signal indicates an insubstantial voltage level for the corresponding one of the power conductors.

Provided is a current measuring device for measuring current, including a conductor (1) adapted to pass current therethrough, and a circuit board (31) with a wire, the wire being adapted to extract a voltage signal from the conductor, in which the circuit board is disposed upright with respect to the conductor.

A readout circuit for resistive and capacitive sensors includes a first input coupled to a reference resistor in a first mode of operation and coupled to a resistive sensor in a second mode of operation; a second input coupled to a capacitive sensor in the first mode of operation and coupled to a reference capacitor in the second mode of operation; and an output for providing a capacitive sensor data stream in the first mode of operation and for providing a resistive sensor data stream in the second mode of operation.

At least two redundant analog input units for a measurement current have analog inputs which are connected in parallel and upon which voltage measuring devices directly lie to convert respectively applied voltages into a digital measurement value, wherein in order to detect errors, in particular in order to detect wire breakage, each analog input unit compares its generated measurement value with a threshold and outputs an error message if a measurement value is detected that falls below the threshold, where if the analog input of the analog input unit is in the low-resistance state, then the at least one other analog input unit is additionally caused to assume a current-measuring function and switch the analog input of the analog input unit to a low-resistance state.