The present invention discloses an electromagnetic detector and a detection method for detection of interface cracks in a piezoelectric-piezomagnetic laminated structure. The electromagnetic detector for detection of interface crack in a piezoelectric-piezomagnetic laminated structure mainly comprises an eddy current magnetic probe assembly, an automatic scanning frame, a base, a carrier, a servomotor, an X-axis mobile frame driving controller, a Y-axis mobile frame driving controller, a power supply, and a main controller.

The present invention discloses an electromagnetic detector and a detection method for detection of interface cracks in a piezoelectric-piezomagnetic laminated structure. The electromagnetic detector for detection of interface crack in a piezoelectric-piezomagnetic laminated structure mainly comprises an eddy current magnetic probe assembly, an automatic scanning frame, a base, a carrier, a servomotor, an X-axis mobile frame driving controller, a Y-axis mobile frame driving controller, a power supply, and a main controller.

A sense circuit for a piezoresistive sensor is provided that comprises: an energy storage circuit coupled to the piezoresistive sensor via a first node; a charge control circuit coupled to the first node and configured to charge the energy storage circuit to a predetermined potential; a discharge control circuit configured to allow the energy storage circuit to discharge through the piezoresistive sensor; and a readout circuit coupled to the first node and configured to output a sensed voltage based on a level of charges stored by the energy storage circuit

The present invention d iscloses an electromagnetic detector and a detection method for detection of interface cracks in a piezoelectric-piezomagnetic laminated structure. The electromagnetic detector for detection of interface crack in a piezoelectric-piezomagnetic laminated structure mainly comprises an eddy current magnetic probe assembly, an automatic scanning frame, a base, a carrier, a servomotor, an X-axis mobile frame driving controller, a Y-axis mobile frame driving controller, a power supply, and a main controller.

The present invention d iscloses an electromagnetic detector and a detection method for detection of interface cracks in a piezoelectric-piezomagnetic laminated structure. The electromagnetic detector for detection of interface crack in a piezoelectric-piezomagnetic laminated structure mainly comprises an eddy current magnetic probe assembly, an automatic scanning frame, a base, a carrier, a servomotor, an X-axis mobile frame driving controller, a Y-axis mobile frame driving controller, a power supply, and a main controller.

Apparatus and associated methods relate to a functional self-test, including (1) generation of an excitation signal, (2) applying the excitation signal to a unit under test (UUT), the excitation signal including a cyclical signal for a first interval and substantially zero signal for a second interval, (3) determining frequency content of a UUT response signal, and (4) generating a fail result in response to the frequency content below a predetermined threshold. In an illustrative example, the UUT may be a piezoelectric element (PE). The UUT response signal may be processed by a filter, for example. A portion of the filtered UUT response signal, responding to the second interval of the excitation signal, may be analyzed by a fast Fourier transform module (FFTm), for example. In various implementations, the functional self-test may advantageously determine the health of a piezoelectric gas sensing element, periodically, in a field-deployed implementation.

Apparatus and associated methods relate to a functional self-test, including (1) generation of an excitation signal, (2) applying the excitation signal to a unit under test (UUT), the excitation signal including a cyclical signal for a first interval and substantially zero signal for a second interval, (3) determining frequency content of a UUT response signal, and (4) generating a fail result in response to the frequency content below a predetermined threshold. In an illustrative example, the UUT may be a piezoelectric element (PE). The UUT response signal may be processed by a filter, for example. A portion of the filtered UUT response signal, responding to the second interval of the excitation signal, may be analyzed by a fast Fourier transform module (FFTm), for example. In various implementations, the functional self-test may advantageously determine the health of a piezoelectric gas sensing element, periodically, in a field-deployed implementation.

Examples provide for a self-test circuit. The self-test circuit comprises input circuitry; testing circuitry; and a circuit to be tested, coupled between the input and testing circuitry and comprising at least a piezoelectric crystal. The input circuitry is configured to generate and transfer a predefined electric signal comprising at least a sinusoidal signal through at least the piezoelectric crystal of the circuit to be tested to generate an output signal. The testing circuitry is configured to analyze the output signal.

Examples provide for a self-test circuit. The self-test circuit comprises input circuitry; testing circuitry; and a circuit to be tested, coupled between the input and testing circuitry and comprising at least a piezoelectric crystal. The input circuitry is configured to generate and transfer a predefined electric signal comprising at least a sinusoidal signal through at least the piezoelectric crystal of the circuit to be tested to generate an output signal. The testing circuitry is configured to analyze the output signal.

Examples provide for a self-test circuit. The self-test circuit comprises input circuitry; testing circuitry; and a circuit to be tested, coupled between the input and testing circuitry and comprising at least a piezoelectric crystal. The input circuitry is configured to generate and transfer a predefined electric signal comprising at least a sinusoidal signal through at least the piezoelectric crystal of the circuit to be tested to generate an output signal. The testing circuitry is configured to analyze the output signal.