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).