An aging detection circuit includes a sensor circuit and a reference circuit. The sensor circuit runs constantly with the operation of the device to be monitored. The sensor circuit can generate a sensor count. The reference circuit is turned off unless enabled for measurement of the device to be monitored. The reference circuit can generate a reference count. The aging detection circuit can include circuitry to determine the aging of the device to be monitored based on a difference between the sensor counter and the reference counter.

A device having a crystal driver to operate according to a voltage transfer curve and a current reference to provide a current bias to the crystal driver to produce a voltage from the crystal driver within a linear region of the voltage transfer curve of the crystal driver, and to determining a gain margin of the crystal driver based on the measured first voltage on the driver output. A method to force a current bias from a current reference on a driver input, to measure the voltage on the driver output within a linear region of the voltage transfer curve of the crystal driver, and determine a gain margin of the crystal driver based on the measured voltage on the driver output.

Cochlear implant systems can include a cochlear electrode and a stimulator in electrical communication with the cochlear electrode. The stimulator can be in communication with a controller, which is in communication with a testing circuit and a switching network. The stimulator can include a plurality of source elements. The controller can control the switching network to place the plurality of source elements into communication with the testing circuit. The controller can further cause one of the plurality of source elements to emit an electrical current and can determine an amount of electrical current emitted from the source element using the testing circuit. The controller can compare the determined amount of electrical current emitted by the source element with a prescribed current. The controller can adjust the output of each of the plurality of source elements based on the determined amount of electrical current emitted by the stimulator.

A power source emulator is provided for testing programmable switchgear that switches to an alternative three-phase power source upon sensing a failure of a grid source. The emulator provides three simulated three-phase power sources for testing switchgear. Each source is identical in voltage and phase to the current normally distributed by the switchgear but has less than 1% of the amperage. Each power source includes a single three-phase contactor for simultaneously controlling all three phases of the power source, and three solid-state relays for controlling each of the three phases of the power source. A control circuit controls the three-phase contactor and each of the three solid state relays of each power source to simulate various types of power failures that the switchgear is programmed to respond to.

A method of inspecting a temperature controlling system is provided. The method includes generating a measurement matrix based on current measurement values of the temperature controlling system, calculating a transformation matrix having the same dimensions as the measurement matrix based on the measurement matrix, calculating an auxiliary matrix having the same dimensions as the measurement matrix based on the transformation matrix, and calculating a defect matrix representing defective diodes among the plurality of diodes, based on a difference operation between the auxiliary matrix and the transformation matrix.

A beauty device including an isolation circuit and a working circuit is provided. A first terminal of the isolation circuit is configured to access a test voltage or output a driving signal, and a second terminal of the isolation circuit is electrically connected to the working circuit. The working circuit is configured to output the driving signal to the isolation circuit.

A housing part (10) for a sensor has a transparent, hollow base body which has a toothing (14) in the form of a straight-toothed gearwheel in a circular-cylindrical emission region on its lateral surface. A circuit board of the sensor is partially arranged in the housing part (10). The circuit board has at least one light source which faces the emission region.

The disclosure relates to monitoring of power electronics modules for multiphase electrical machines, in particular to determine the presence or absence of a fault. Example embodiments include a method of monitoring a system (100) comprising first and second multiphase electrical machines (101.sub.1, 101.sub.2) driven by respective first and second inverters (102.sub.1, 102.sub.2) from respective first and second DC electrical supplies (103.sub.1, 103.sub.2), the method comprising measuring DC link currents and voltages (Idc1, Idc2, Vdc1, Vdc2), stator currents and voltages (Ia1, Ib1, Ic1, Ia2, Ib2, Ic2, Va1, Vb1, Vc1, Va2, Vb2, Vb3), calculating on-state voltage, on-state resistance and turn-off delay for the inverters (102.sub.1, 102.sub.2) and an equivalent series resistance of the inverters (102.sub.1, 102.sub.2), calculating ratios of the calculated values and determining the presence or absence of a fault in the inverters (102.sub.1, 102.sub.2) based on a combination of two or more of the ratios.

A capacitance acquiring unit acquires a plurality of initial capacitance values indicating capacitance values of a smoothing capacitor in an initial state and acquires a plurality of operation capacitance values indicating capacitance values of the smoothing capacitor in an operation state, and a deterioration determining unit acquires characteristic information indicating a relationship between AC power and the capacitance value of the smoothing capacitor in the initial state on the basis of a statistic amount of the plurality of initial capacitance values acquired by the capacitance acquiring unit and determines a deterioration state of the smoothing capacitor on the basis of a statistic amount of the plurality of operation capacitance values acquired by the capacitance acquiring unit and the characteristic information.