The disclosure relates to a device for measuring electrical current in an electrical conductor (2), the device comprising: a measuring circuit configured to be connected to the electrical conductor, the measuring circuit comprising: a resistor based measuring circuit comprising a resistor (10), a transformer based measuring circuit comprising a current transformer (20) comprising a primary coil (20a), connected in series with the resistor (10) of the resistor based measuring circuit, a first inverter (12) configured to transform a first digital signal using a transfer function being an inverse of a transfer function representing the resistor based measuring circuit; a second inverter (22) configured to transform a second digital signal using a transfer function being an inverse of a transfer function representing the transformer based measuring circuits; and a signal combiner (5) configured to combine the transformed first and second digital signals, thereby providing a digital signal representing the electrical current in the electrical conductor. The disclosure also relates to a method for measuring electrical current in an electrical conductor.

A current sensing circuit includes a current detection unit having a first resistance element; a first MOS-transistor and a first constant current source connected between a first output end of the current detection unit and a ground terminal; a second MOS-transistor and a second constant current source connected between a second output end of the current detection unit and the ground terminal; a third MOS-transistor having a source connected to the first output end and a gate connected to a drain of the second MOS-transistor; a second resistance element connected between an output terminal and the ground terminal; and a high withstand-voltage MOS-transistor connected between the third MOS-transistor and the output terminal to receive a predetermined control voltage, wherein the gates of the first and second MOS-transistors are commonly connected, and the gate of the first MOS-transistor is connected to the drain thereof.

Disclosed is a directional coupler having a coupler, a forward resistive attenuator, a reflected resistive attenuator, a forward compensation capacitor, and a reflected compensation capacitor. A forward coupler side arm and reflected coupler side arm of the coupler are configured to obtain a sample of forward energy and a sample of reflected energy from the coupler transmission line section. The forward resistive attenuator and reflected resistive attenuator are configured to attenuate the sample of forward energy and the sample of reflected energy. The forward compensation capacitor and the reflected compensation capacitor are configured to receive the attenuated sample of forward energy and the attenuated sample of reflected energy and produce a frequency-compensated sample of forward energy and a frequency-compensated sample of reflected energy.

An electronic overload current breaker supports arc-fault and ground-fault (AFGF) detection along with built-in shunt calibration (BISC). The breaker may include a current sensing shunt and a control circuit electrically coupled to the current sensing shunt. This control circuit is configured to calibrate the current sensing shunt in response to application of a calibration current to the breaker. The control circuit can: (i) determine a magnitude of the calibration current applied to the breaker, (ii) map the magnitude of the calibration current to a first one of a plurality of current ratings for the breaker, and (iii) set the breaker to monitor overload conditions at the first one of the plurality of current ratings. The plurality of current ratings for the breaker can be less than the magnitude of the calibration current.

One example discloses a current monitoring device, including: a sense impedance configured to receive a current to be monitored; an impedance divider, coupled to the sense impedance, and configured to convert the current to be monitored to a differential voltage to be monitored; a reference circuit configured to generate a differential reference voltage; a comparator coupled to the impedance divider and the reference circuit and configured to output a signal if the differential voltage to be monitored is different than the differential reference voltage; and wherein the reference circuit includes a comparator trimming circuit configured to vary the differential reference voltage to compensate for offset biases in the comparator.

A shunt strip that includes a plurality of shunts arranged in a grid with each of the shunts spaced from an adjacent shunt by a shunt-gap. A plurality of tabs connect the plurality of shunts and at least one tab is positioned within each shunt-gap. Also, a shunt with a generally parallelepiped shaped body has severed tab portions extending outwardly and downwardly from the body.

An electronic measuring device includes a main printed circuit assembly and one or a plurality of channel modules. At least one channel module includes a channel printed circuit board and a first insulating housing that defines a cavity covering at least part of electrical elements mounted on the channel printed circuit board. A first conductive shielding frame is at least partially disposed on the first insulating housing and separated from the channel printed circuit board via the first insulating housing. The first conductive shielding frame covers the at least part of the electrical elements mounted on the channel printed circuit board. A second insulating housing on the first conductive shielding frame is configured to sandwich the first conductive shielding frame between the second insulating housing and the first insulating housing so as to lengthen an electrical path from the first conductive shielding frame to the channel printed circuit board.

The present disclosure provides a current detection system, method and device. The current detection system includes a management unit and a current detection device that is connected with the management unit. The current detection device includes a shunt-type current measurement unit, an open-loop Hall-type current measurement unit and an isolation power unit.

A testing apparatus includes a holster including a jack defining a conductive periphery configured to connect with a reference lead of the voltage probe to form a common ground. The apparatus includes a shunt defining first and second regions of different potential having predetermined difference. The second region is configured to connect with a reference lead of the shunt probe. The apparatus includes a bridge configured to connect the shunt probe lead with the common ground.

A difference amplifier can he used for providing an amplified representation of a sensed current through a load device. A separate signal path can be used to provide fast fault detection, without requiring use of the difference amplifier. For example, a voltage scaling circuit can be used to scale a differential input signal indicative of the load current. The scaled representation can then be compared against a specified threshold corresponding to a fault current value. In this manner, a high-speed low-voltage comparator can be used to provide detection of a fault current that otherwise exceeds an input range of the difference amplifier, where the difference amplifier is used separately for precision current monitoring. As an illustrative example, such a scheme can provide fault detection even when an input of the difference amplifier is saturated.