| 摘要 |
The invention concerns a detecting device for detection of introduction and/or removal of metal objects into/from a sensing area surrounding the detector, said detector comprising a first loop and a drive circuit to pass a current through said first loop. The device in accordance with the invention is characterised in that it further comprises a second loop arranged in such a manner relative to the first loop that, in a normal state without the presence of metal objects, substantially no current is generated in the second loop from the magnetic field of the first loop but that in a state of interference, in which a metal object is entered into the sensing area, a current is generated in the second loop, and in that the device further comprises a detecting unit for detecting modifications arising in the current in the second loop. |
