In manufacturing method of a cylindrical piezoelectric element, a cylindrical piezoelectric material is formed by molding a piezoelectric material into a cylindrical shape and subjecting the molded piezoelectric material to calcination. A reference electrode is provided on an inner circumferential surface of the cylindrical piezoelectric material. Drive electrodes are provided in a circumferential direction so that the drive electrodes are extending in an axial direction from one end to the other end on an outer circumferential surface. A polarization electrode is provided at a part of the circumferential surface in the vicinity of the one end. A predetermined voltage is applied between the polarization electrode and the reference electrode. The polarization electrode is removed from the cylindrical piezoelectric material.

A passive and wireless sensor is provided for sensing at least one of magnetic field, temperature or humidity. The sensor can provide only one of the sensing functions, individually or any combination of them simultaneously. It can be used for various applications where magnetic field changes, temperature and/or humidity need to be measured. In one or more embodiments, a surface acoustic wave (SAW) sensor is provided that can measure one or more of a magnetic field (or current that generates the magnetic field), temperature and humidity. In one or more embodiments, a magnetoimpedence (MI) sensor (for example a thin film giant magnetoimpedance (GMI) sensor), a thermally sensitive (for example a Lithium Niobite (LiNbO.sub.3)) substrate, and a humidity sensitive film (for example a hydrogel film) can be used as sensing elements.

An illustrative humidity sensor may include a substrate and a sensing field effect transistor. The sensing field effect transistor may comprise a source formed on the substrate, a drain formed on the substrate, a gate, and a piezoelectric layer disposed over the gate. Another illustrative humidity sensor may comprise a substrate, a semi-conductor layer disposed over the substrate, a piezoelectric layer disposed over the semi-conductor layer, a first electrode disposed on the piezoelectric layer, and a second electrode disposed on the piezoelectric layer. In some instances, the piezoelectric layer may comprise aluminum nitride.

An actuator device has an electroactive polymer actuator and an integrated piezoelectric transformer. At least a secondary side of the integrated piezoelectric transformer shares a piezoelectric electroactive polymer layer with the electroactive polymer actuator, so that lower external voltages can be applied to the actuator device. A diode is connected between the secondary side of the integrated piezoelectric transformer and the electroactive polymer actuator.

A piezoelectric transformer that includes a base and an upper layer supported by the base. The upper layer includes a first piezoelectric layer that includes the portion of the upper layer that is interposed between an output electrode and an intermediate electrode, and a second piezoelectric layer that is superposed with the first piezoelectric layer and includes the portion of the upper layer interposed between the intermediate electrode and an input electrode in at least n vibration portions. Moreover, the input electrode includes multiple input electrode pieces and the output electrode includes multiple output electrode pieces. In addition, wiring lines are routed such that voltages of opposite phases can be respectively applied to a first input electrode piece group and a second input electrode piece group with the potential of the intermediate electrode serving as a reference.

A control circuit and a method for controlling a piezoelectric transformer are disclosed. In an embodiment the control circuit includes an inductor and a control unit, wherein the control circuit is configured to apply a voltage with a periodic waveform to a piezoelectric transformer, wherein a period duration of the voltage is specified by a control frequency and adjust the control frequency of the applied voltage as a function of an average current intensity of a current flowing through the inductor.

An apparatus (100) for generating a high voltage or high field strength and a component (200) for generating a high voltage or high field strength are disclosed. A means (20) that is provided in a defined area (23) of the cylindrical and dielectric housing (11) or the sleeve (202) of the component (200). The means (20) ensures that, in a space (15) of the defined area (23), between the piezoelectric transformer (1) and an inner wall (14) of the dielectric housing (11), an essentially symmetrical field distribution (16) prevails. Even with an external influence (80), the field distribution (16) is influenced in such a way that an ignition field strength in space (15) of the defined area (23) is avoided.

A piezoelectric composition containing: at least one or more elements selected from alkali metal elements; at least one or more elements selected from a group consisting of vanadium, niobium, and tantalum; copper or copper and germanium; and oxygen. The piezoelectric composition has a main phase, and a high Cu-concentration phase in which a content ratio of copper is higher than the main phase, and when a content ratio of oxygen in the high Cu-concentration phase is set as O.sub.g, and a content ratio of copper is set as Cu.sub.g, O.sub.g and Cu.sub.g satisfy relationships of 51≤O.sub.g≤60 and 2.0≤Cu.sub.g≤15.

The present disclosure relates to circuitry for driving a piezoelectric transducer. The circuitry may be implemented as an integrated circuit and comprises driver circuitry configured to supply a drive signal to the piezoelectric transducer to cause the transducer to generate an output signal and active inductor circuitry configured to be coupled with the piezoelectric transducer. The active inductor circuitry may be tuneable to adjust a frequency characteristic of the output signal.

A printed circuit board comprises a first mounting surface, a second mounting surface, and a piezoelectric transformer. The piezoelectric transformer has a piezoelectric substance, external electrodes, and a frame substrate. The second mounting surface has a projection region. There is a first region from a first location, where an end portion further from the output electrode out of end portions of the input electrode is projected onto the second mounting surface in the projection region, to a second location, where an end portion closer to the output electrode out of the end portions of the input electrode is projected onto the second mounting surface, the first region being a mounting allowed region where an electronic component is mounted.