A current detection system includes an inductor and a detection circuit coupled across the inductor. The inductor is configured to receive an input signal that includes an input current and generate a voltage across the inductor. The current detection circuit includes a sensing network and a transconductance amplifier. The sensing network includes a capacitor and is configured to monitor a voltage across the inductor. The transconductance amplifier is configured to receive a differential voltage indicative of a voltage drop across the capacitor and output a differential output current proportional to the differential voltage.

A current detection system includes an inductor and a detection circuit coupled across the inductor. The inductor is configured to receive an input signal that includes an input current and generate a voltage across the inductor. The current detection circuit includes a sensing network and a transconductance amplifier. The sensing network includes a capacitor and is configured to monitor a voltage across the inductor. The transconductance amplifier is configured to receive a differential voltage indicative of a voltage drop across the capacitor and output a differential output current proportional to the differential voltage.

A calibration system adapted to calibrate a resistance of an electrical device having a lead wire comprises a resistance detector adapted to detect the resistance of the electrical device, a first container containing an etching solution adapted to etch the lead wire, and a heater configured to heat the electrical device. If a first resistance of the electrical device detected by the resistance detector at a first temperature is within a first predetermined range, the electrical device is heated with the heater to a second temperature higher than the first temperature. A second resistance of the electrical device is detected by the resistance detector at the second temperature. If the second resistance is beyond a second predetermined range, the lead wire is etched by the etching solution to adjust the resistance of the electrical device until the second resistance at the second temperature is within the second predetermined range.

An apparatus for checking an inductor includes a detector outputting a detection signal including information corresponding to a parallel resistance component of a checking target inductor; and a determiner receiving the detection signal and determining whether the checking target inductor is satisfactory based on a magnitude of the parallel resistance component.

A current detection system includes an inductor and a detection circuit coupled across the inductor. The inductor is configured to receive an input signal that includes an input current and generate a voltage across the inductor. The current detection circuit includes a sensing network and a transconductance amplifier. The sensing network includes a capacitor and is configured to monitor a voltage across the inductor. The transconductance amplifier is configured to receive a differential voltage indicative of a voltage drop across the capacitor and output a differential output current proportional to the differential voltage.

A method for monitoring degradation of at least one component in a power system comprising a motor drive circuit configured to provide AC power from a power source to power a motor. The method includes isolating the motor drive circuit from the power source; injecting a test signal to at least one component of the isolated motor drive circuit; and measuring a propagated signal resulting from the injected test signal propagating through the at least one component. The propagated signal may be compared to a test signal and, if the propagated signal differs from the test signal by a threshold, then degradation of the at least one component may be identified.

A jumper has a connector and a housing. The housing at least partially encloses a processor in data communication with a non-transitory memory, a global positioning system, a rechargeable battery, and a networking device. The memory comprises software instructions that, when executed by the processor, perform steps for wirelessly transmitting data to a mobile device over a network. The data indicates a jumper identification number, a location of the jumper, and a duration after which the jumper will automatically deactivate. The steps performed include the step of wirelessly outputting an alert to the mobile device when the mobile device is at a first distance from the jumper. The first distance is settable using the mobile device. The alert causes the mobile device to at least one of vibrate and ring.

This disclosure refers to a method for confectioning resistors that each comprise a PTC ceramic plate and metallic electrode layers covering opposite faces of the ceramic plate, said method comprising the following steps: measuring an electrical resistance of a resistor to be confectioned by applying an electrical potential to one of electrode layers such that an electric current flows from one of the electrode layers through the ceramic plate to the electrode layer on the opposite face of the ceramic plate, comparing the measured resistance to a target resistance, and removing, if the measured resistance is lower than the target resistance, a section of at least one of the electrode layers. This disclosure also refers to such a resistor and a heating device comprising such resistors.