摘要 |
<p>An eddy current probe, excitable at frequencies equal to or greater 7 mhz., includes a substantially planar, spiral-like, unilaminar coil mounted on an insulative substrate. A protective layer covers the coil and is adopted to present only a minimal mechanical barrier between the coil and a region of material under test. The coil is a continuous run of copper having an effective diameter no greater than 2 mils. The coil, substrate and protective layer are a printed circuit board. A method of detecting flaws is also disclosed.</p> |