The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 14, 1982
Filed:
Mar. 03, 1980
Bertram A Auld, Menlo Park, CA (US);
The Board of Trustees of the Leland Stanford Junior University, Palo Alto, CA (US);
Abstract
In ferromagnetic resonance (FMR) probe apparatus for detecting surface flaws in a metal surface, probe impedance changes resulting from flaws are distinguished from impedance changes resulting from probe lift-off from the metal surface. A constant magnitude dc magnetic field and a constant frequency and constant magnitude rf magnetic field are applied to the ferromagnetic crystal and the real and imaginary components of probe impedance are detected. The impedance changes due to flaws are at least partially orthogonal to the impedance changes due to lift-out, and by observing probe impedance on an oscilloscope the presence of a flow or the occurrence of lift-off are readily identified.