An industrial process field device includes a piezoelectric transducer, a sensor circuit, a test circuit, a controller and a communications circuit. The sensor circuit generates a sensor signal indicating a process variable based on a voltage across the piezoelectric transducer. The test circuit is configured to apply a voltage pulse having a pulse voltage to the piezoelectric transducer that induces a response signal, and capture peak positive and negative voltages of the response signal. The controller calculates a current condition value of the piezoelectric transducer based on the peak positive voltage, the peak negative voltage and the pulse voltage, and generates a diagnostic test result based on a comparison of the current condition value to a reference condition value corresponding to a properly operating piezoelectric transducer. The communications circuit communicates the process variable and the diagnostic test result to an external control unit over a process control loop.

The construction has two piezoelectric transducers with radiating apertures shaped as sections of spherical surface one is concave, the second is convex, of sufficient wave sizes D/λ>10, where D is the diameter of the aperture, λ is the wavelength of the emitted pump signal). For each piezoelectric transducers radii of curvature R.sub.0, focal lengths F.sub.0 and focal spots radii r.sub.0 with a wave length of radiated signal are the same and are related by r.sub.0×R.sub.0=0.61×λ×F.sub.0. Piezoelectric transducers with radiating apertures shaped as sections of spherical surface are provided with shielding elements, hydro-, electric- and noise insulation and one of them with convex aperture is made with an open axial hole with radius r=(2÷3)×r.sub.0 in the central part of the convex spherical surface of the aperture.

Provided is a tactile vibration generator comprising; a supporting block, a vibration plate, and a vibration actuator, wherein the vibration plate comprises a first part, which is not in contact with the supporting block, and a second part, which is fixed to the supporting block, and the vibration actuator is attached to a surface of the first part.

An ultrasonic transducer for wind turbine applications. The transducer includes a housing with a central diaphragm portion, a peripheral wall thereabout, and a flexure portion supporting the diaphragm portion relative to the peripheral wall. The apex of a cone is secured to the housing central diaphragm portion and the cone has a peripheral rim secured to the metal housing peripheral wall. A driver such as a piezoelectric element is secured to the housing central diaphragm portion opposite the cone apex.

Aspects of this disclosure relate to driving a capacitive micromachined ultrasonic transducer (CMUT) with a pulse train of unipolar pulses. The CMUT may be electrically excited with a pulse train of unipolar pulses such that the CMUT operates in a continuous wave mode. In some embodiments, the CMUT may have a contoured electrode.

Aspects of this disclosure relate to a capacitive micromachined ultrasonic transducer (CMUT) with a contoured electrode. In certain embodiments, the CMUT has a contoured electrode. The electrode may be non-planar to correspond to a deflected shape of the outer plate. A change in distance between the electrode and the plate after deflection may be greater than a minimum threshold across the width of the CMUT.

Embodiments include a primary short circuit (PSC) coupled to a primary side of a transformer and a dampening element, coupled to a transducer coupled to a secondary side of the transformer, configured to dampen a received signal during a portion of a reverberation period. The PSC and the dampening element may be activated substantially simultaneously. Activation of the PSC circuit mitigates a parallel resonance otherwise arising, in part, in the transducer, but, increases the received signal by a DC shift voltage. The dampening element dampens the DC shift voltage. The received signal may be dampened prior to amplification of the received signal by an amplifier. The dampening facilitates earlier and more precise measurement, during the reverberation period, of at least one operating characteristic for the PAS sensor. Another embodiment prevents the DC shift voltage by selectively activating the PSC within a determined time of a zero-crossing of a given signal.

An ultrasonic transducer positionable in a wellbore environment may include a piezoelectric material layer, a protective layer, and connecting plate positioned between the piezoelectric material layer and the protective layer. The piezoelectric material layer may be formed as a plurality of columns of piezoelectric material for detecting a characteristic of the wellbore environment during a drilling operation. The protective layer may be positionable between the piezoelectric material layer and an acoustic medium in the wellbore environment. The connecting plate may be positioned between the piezoelectric material layer and the protective layer. The connecting plate may have a coefficient of thermal expansion (CTE) in a range between the CTE of the piezoelectric material layer and that of the protective layer, and an acoustic impedance in a range between the acoustic impedance of the piezoelectric material layer and that of the protective layer.

Ultrasonic transmitting elements in an electroacoustical transceiver transmit acoustic energy to an electroacoustical transponder, which includes ultrasonic receiving elements to convert the acoustic energy into electrical power for the purposes of powering one or more sensors that are electrically coupled to the electroacoustical transponder. The electroacoustical transponder transmits data collected by the sensor(s) back to the electroacoustical transceiver wirelessly, such as through impedance modulation or electromagnetic waves. A feedback control loop can be used to adjust system parameters so that the electroacoustical transponder operates at an impedance minimum. An implementation of the system can be used to collect data in a vehicle, such as the tire air pressure. Another implementation of the system can be used to collect data in remote locations, such as in pipes, enclosures, in wells, or in bodies of water.

An electroacoustic transducer, comprising a piezoelectric part comprising a piezoelectric material having a first acoustical impedance and an acoustical thickness, a substrate part comprising a material having a second acoustical impedance, and an intermediate part comprising a material having a third acoustical impedance and at least partially sandwiched between the piezoelectric part and the substrate part for acoustical communication therewith. The first acoustical impedance and the second acoustical impedance each has a respective value within a range of values for which the value of third acoustical impedance: is an upper limit if said acoustical thickness is less than 0.4Λ, or is a lower limit if said acoustical thickness is greater than 0.4Λ where Λ is an acoustical wavelength in the material of the piezoelectric part.