A method and apparatus for sensing a common mode feedback current are provided. The common mode feedback current may flow through a common mode resistive divider of a piezoresistive bridge. A first current mirror mirrors the common mode feedback current and provides a first mirrored common mode current. A current aggregation stage receives the first mirrored common mode current and determines a bridge current of the piezoresistive bridge based on the first mirrored common mode feedback current. A second current mirror may be used to mirror the first current mirror before determining the bridge 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.

The subject matter of this specification can be embodied in, among other things, a method for characterizing a fluid injector that includes receiving a collection of waveform data, identifying a pull locus, determining a detection threshold level value, identifying a first subset of the collection of data representative of a selected first electrical waveform of the collection of electrical waveforms, identifying an opening value, identifying a representative closing value, identifying an anchor value, identifying a second subset of the collection of data based on the collection of data, the pull locus, the first subset, and the opening value, identifying a maximum electrical value, identifying an opening locus based the collection of data, the anchor value, and the maximum electrical value, identifying a hold value, and providing characteristics associated with the fluid injector comprising the pull locus, the opening locus, the hold value, the anchor value, and the representative closing value.

The subject matter of this specification can be embodied in, among other things, a method for characterizing a fluid injector that includes receiving a collection of waveform data, identifying a pull locus, determining a detection threshold level value, identifying a first subset of the collection of data representative of a selected first electrical waveform of the collection of electrical waveforms, identifying an opening value, identifying a representative closing value, identifying an anchor value, identifying a second subset of the collection of data based on the collection of data, the pull locus, the first subset, and the opening value, identifying a maximum electrical value, identifying an opening locus based the collection of data, the anchor value, and the maximum electrical value, identifying a hold value, and providing characteristics associated with the fluid injector comprising the pull locus, the opening locus, the hold value, the anchor value, and the representative closing value.

An embodiment of the present invention makes it possible to carry out stable inspection on performance of a touch panel. An inspection device for inspecting a touch panel on a basis of a resistance value of a transparent film of the touch panel, which includes at least the transparent film, a dielectric member, and a sensor stacked on top of each other, includes: an integrating circuit configured to obtain a background capacitance of the touch panel by applying a first pulsed voltage to the sensor; and a switch configured to connect the transparent film to a ground or to a generator configured to generate a second pulsed voltage which is opposite in phase to the first pulsed voltage.

An embodiment of the present invention makes it possible to carry out stable inspection on performance of a touch panel. An inspection device for inspecting a touch panel on a basis of a resistance value of a transparent film of the touch panel, which includes at least the transparent film, a dielectric member, and a sensor stacked on top of each other, includes: an integrating circuit configured to obtain a background capacitance of the touch panel by applying a first pulsed voltage to the sensor; and a switch configured to connect the transparent film to a ground or to a generator configured to generate a second pulsed voltage which is opposite in phase to the first pulsed voltage.

A system for an aircraft includes an aircraft component that includes a heater routed through the aircraft component, the heater including a resistive heating element and insulation surrounding the resistive heating element. A first current flows into the resistive heating element to provide heating for the aircraft component and a second current flows out of the resistive heating element. The system further includes a first sensor configured to produce a first sensor signal representing the first current, a second sensor configured to produce a second sensor signal representing the second current, a leakage sensor configured to produce a leakage sensor signal representing a leakage current, and a signal processor configured to sample and measure the first current, the second current, and a leakage current using a high frequency sampling rate to identify the presence of electric arcing. The detection of electric arcing is used to predict future heater failure and estimate heater remaining useful life.

In a bridge circuit, a series circuit in which a first resistor and a second resistor are connected in series and the second resistor and a fourth resistor are connected in series is formed. In the bridge circuit, the series circuit is connected to a load portion in parallel, one end of a fifth resistor is connected between the second resistor and the fourth resistor, and the other end of the fifth resistor is connected between the first resistor and the load portion. In the bridge circuit, a voltage supply unit is connected between the first resistor and the second resistor. A controller detects an abnormality of the load portion based on a detection voltage of the bridge circuit detected by applying a voltage from the voltage supply unit with a switch turned off. With this configuration, an abnormality detection device can detect abnormality while suppressing an increase in size.

Voltage-dividing resistors are arranged in parallel with a first DC power supply. A first switch is electrically connected to a first resistor and a second resistor and includes a first terminal, a second terminal, and a control terminal. A second switch switches supply of a power voltage from a second DC power supply. A voltage comparator includes a first and a second input terminals. A reference power supply is connected to the first input terminal of the voltage comparator and outputs a reference voltage. The first terminal of the first switch is electrically connected to the second input terminal of the voltage comparator. The control terminal of the first switch is electrically connected to a positive voltage side of the second DC power supply. When the power voltage is supplied to the control terminal, and allows a voltage to be applied to the first and the second resistors.

A current sensor can indirectly measure a sensed current by directly measuring static perturbing AC magnetic fields with magnetoresistance elements, the perturbing magnetic fields generated by perturbing coils. The sensed current can be indirectly measured by modulating or changing sensitivities of the magnetoresistance elements in a way that is directly related to the sensed current.