A piezoelectric transformer and a method for producing a piezoelectric transformer are disclosed. In an embodiment, the method includes manufacturing a main body having an input region having electrodes and a first piezoelectric material being alternately stacked one on top of the other. An output region includes a second piezoelectric material. The first piezoelectric material is polarized and a removable contact is fitted to an output-side end side of the main body, which end side faces away from the input region. A first electrical potential is applied to the removable contact for polarizing the second piezoelectric material.

A method for frequency control of a piezoelectric transformer and a circuit arrangement including a piezoelectric transformer are disclosed. In an embodiment, the method includes exciting a piezoelectric transformer on an input side with an AC voltage of predetermined frequency as input voltage, capturing a phase information for an input impedance of the piezoelectric transformer in a feedback path, evaluating the captured phase information in respect of a predetermined phase criterion, and regulating the frequency of the AC voltage on a basis of the evaluated phase information.

What is specified is a piezoelectric transformer (10) having a surface structure which has at least one protruding surface structure segment (5), wherein the piezoelectric transformer has a contour (3) and is suitable for discharging a gas in conjunction with a counter electrode (10) for generating a plasma, wherein the surface structure is configured such that the gas discharge takes place at a multiplicity of discharge initiation points (6) on the contour (3). A width of the surface structure segment (5) is smaller than the width of the piezoelectric transformer (1).

An apparatus for generating an atmospheric pressure plasma is disclosed. In an embodiment an apparatus includes a first support element and a piezoelectric transformer supported by the first support element, wherein the piezoelectric transformer is supported at a position at which an oscillation node is formed when the piezoelectric transformer is operated at an operating frequency that is lower than its parallel resonant frequency, and wherein the piezoelectric transformer is configured to generate a non-thermal atmospheric pressure plasma.

A method of operating a piezoelectric plasma generator including applying an input signal to a piezoelectric transformer of the piezoelectric plasma generator. An absolute value of a peak amplitude of the input signal is periodically reduced and increased to a level smaller and larger than an ignition voltage of the plasma generator, such that plasma generation periodically collapses.

The invention relates to an assembly for treating wounds and to a hand held unit for treating wounds. The assembly and the hand held unit comprise a device for producing a plasma and/or an excited gas or gas mixture by means of a piezoelectric transformer, which is housed together with a circuit board in a housing of the device, and the assembly comprises an expansion element. A control circuit, to which the piezoelectric transformer is electrically connected, is realized on the circuit board. A second end of the expansion element surrounds a wound region to be treated. A first end of the expansion element is detachably connected to the housing of the device at the opening of the housing. The produced plasma and/or excited gas or gas mixture thus enters the expansion element from the opening of the housing.

A piezoelectric transformer is disclosed In an embodiment a piezoelectric transformer includes a cylindrical base body with an input region and an output region, wherein a cylinder axis of the base body extends in a longitudinal direction, wherein the input region is configured to convert an AC voltage into a mechanical vibration, wherein the output region is configured to convert a mechanical vibration into an electrical voltage, wherein the output region includes a single piezoelectric layer polarized in the longitudinal direction, wherein, in the input region, a first piezoelectric layer, on which a first internal electrode is arranged, and a second piezoelectric layer, on which a second internal electrode is arranged, are wound onto one another, and wherein the first piezoelectric layer and the second piezoelectric layer are polarized in a radial direction which is perpendicular to the longitudinal direction.

A device (1) comprising an electro-ceramic component (2) which has a first electrical contact (3A), provided on a first side face (2A) of the electro-ceramic component (2) in the excitation zone (11), and a second electrical contact (3B) provided on a second side face (2B) of the electro-ceramic component (2). A sealing compound (20) is placed around the electro-ceramic component (2) so that the first electrical contact (3A) and the second electrical contact (3B) are covered by the sealing compound (20) and a free end (26) of a section (24) of the high-voltage zone (12) of the electro-ceramic component (2) projects beyond a free end (22) of the sealing compound (20).

A plasma generator and a method for setting an ion ratio. In an embodiment a plasma generator includes a piezoelectric transformer suitable for ionizing a process gas, an ion separation electrode and a drive circuit suitable for applying a potential to the ion separation electrode.

In an embodiment a device includes a low voltage assembly having an output contact, the low voltage assembly configured to provide a low voltage at the output contact, a high voltage assembly having an input contact and a transformer and a plug-in connection interconnecting the low voltage assembly and the high voltage assembly, wherein the plug-in connection is configured to provide an electrical contact between the output contact of the low voltage assembly and the input contact of the high voltage assembly, wherein the low voltage provided at the output contact is applied to the transformer via the input contact, wherein the transformer is configured to convert the low voltage into a high voltage, and wherein the device is configured to generate a gas discharge.