Abstract: A search coil assembly for an inductive search device of the transmitter/receiver type is described having advantages relative to manufacture, repeat accuracy and sensitivity in operation. This is made possible by the utilization of printed-circuit board technology in search coil construction in which electrically conductive windings in the form of a conductor band of circuit tracks are arranged side-by-side at the periphery of partial areas on a carrier layer common to the partial areas.

Abstract: A rotary head for scanning the surface of elongated test materials (62) by eddy current transducers (60) is additionally provided with means for magnetization of the test material (62) over an intended test range making it now possible to achieve sensitive testing of non-bare ferromagnetic bars and wires, testing for "smeared cracks" where surface has closed above the material separation, and testing of welded austenitic pipes. For the magnetization, parts of the housing (10) as well as a rotating hollow shaft (40) are employed in the conduction of magnetic flux, and special measures are taken for the homogenization of the magnetic field in the test range.