| 摘要 |
<p>Eddy current probes for detecting internal defects in a ferromagnetic tube are disclosed. The probe uses a plurality of eddy current measuring means, each being operated at a different operating point on the impedance diagram. By operating more than one such eddy current measuring means simutaneously, noises by, for example, permeability variation of a ferromagnetic material and internal magnetic deposit, can be made less influential.</p> |
