An apparatus and a method for generating a non-thermal atmospheric pressure plasma are disclosed. In an embodiment, an apparatus for generating a non-thermal atmospheric-pressure plasma includes a first piezoelectric transformer, a second piezoelectric transformer, and a drive circuit configured to apply an input voltage to each of the piezoelectric transformers, and wherein the input voltage applied to the first transformer is phase-shifted by 90 in relation to the input voltage applied to the second transformer.

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.

A device for generating a non-thermal atmospheric pressure plasma is disclosed. In an embodiment a device includes a first piezoelectric transformer configured to ignite a non-thermal atmospheric pressure plasma in a process medium and a control circuit configured to apply an input voltage to the first piezoelectric transformer and to perform a modulation of the input voltage such that the first piezoelectric transformer generates an acoustic signal as a result of the modulation.

A plasma generator is disclosed. In an embodiment a plasma generator includes a piezoelectric transformer subdivided into an input region and an output region in a longitudinal direction, wherein the piezoelectric transformer comprises an output-side end face facing away from the input region, wherein the plasma generator comprises a passive load arranged permanently in front of the output-side end face, and wherein the plasma generator is configured to generate non-thermal atmospheric-pressure plasma.

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.

A piezoelectric transformer comprises at least a laminate of a first member, a first piezoelectric element, a second piezoelectric element and a second member sequentially stacked one on the other in the above-listed order and a pressurizing mechanism for squeezing the first member and the second member together in the stacking direction. The ratio of the electromechanical coupling coefficient k.sub.33 relative to the electromechanical coupling coefficient k.sub.31 (k.sub.33/k.sub.31) of the first piezoelectric element and the second piezoelectric element is not less than 2.0.

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.

A power converter including at least one piezoelectric element in a branch of a bridge of switches, the switches being controlled to alternate phases at substantially constant voltage and at substantially constant charge between the terminals of the piezoelectric element.

A device for generating an atmospheric-pressure plasma is disclosed. In an embodiment the device includes a piezoelectric transformer comprising an input region and an output region, wherein the input region is designed to convert an applied alternating voltage into a mechanical oscillation, wherein the output region is designed to convert a mechanical oscillation into a voltage, and wherein the output region adjoins the input region in a longitudinal direction, a contact element fastened to the piezoelectric transformer, the contact element being designed to apply the alternating voltage to the input region and a holder, wherein the contact element is connected to the holder by a form-fit connection, in such a manner that a movement of the piezoelectric transformer in the longitudinal direction, relative to the holder, is prevented.

A device for producing a non-thermal atmospheric-pressure plasma are a method for frequency control of a piezoelectric transformer are disclosed. In an embodiment a device includes a piezoelectric transformer, an activating circuit configured to apply an AC voltage at an activating frequency to the piezoelectric transformer as an input voltage and a field probe configured to measure a field strength of an electric field produced by the piezoelectric transformer, wherein the activating circuit is configured to adapt the activating frequency based on the measurement results of the field probe such that a field strength is maximized.