Improved method and apparatus for detecting and locating residually magnetized items

摘要

Methods and apparatus for detecting and locating residually magnetized misplaced tools and the like are disclosed. A sensitive gradiometer having a hand-held probe provides a balanced, phase cancelling magnetic field. The presence of a weak residual mangetic field emanating from the misplaced tool upsets the balance of the generated field, and this imbalance provides an audio signal which is used to locate the tool.