FIELD: non-destructive flaw detection, in particular, using piezoelectric transducers. SUBSTANCE: surfaces of piezoelectric cell are shaped as rotation body of closed flat figure about its axis, which is perpendicular to base of piezoelectric cell. Flat generating figure is designed as convex polygon, which has at least four sides. Angles of polygon and size of piezoelectric cell conform to specific conditions. In addition, piezoelectric cell may be designed as ring, which is produced by rotation of generating polygon about outer axis. Size of ring also conforms to specific conditions. EFFECT: increased bandwidth, almost trapezoid shape of amplitude- frequency response. 2 cl, 7 dwg
