GMR sensors and inductors for detection of metal / magnetic fields

Oct 11, 2006 1 Replies
S

Hello everyone, I have a question about metal detection and magnetic fields and such.



I know that inductors and GMR sensors can both be used to detect magnetic fields and/or metal objects, but I was wondering about the difference in usage between them. I think I have a pretty good understanding, but I was hoping someone could explain the difference between the two to me..


And inductor is affected by a magnetic field or when a conducting object enters into its own field, am I correct? How is this different from GMR sensor detection?


Thanks for any help!


--Steven



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J

I think GMR type sensors are used to measure the disturbances in the Earth's magnetic field caused by ferromagnetic objects and ores. Inductive methods involve generating an AC field with a coil and either measuring the alterations in the coil's inductance caused by the field passing through magnetic and/or conductive objects, or measured by the effect of the objects on the signal generated by this AC field on one or two additional coils.

With two coils, you can arrange their signals to cancel so that the conductive or magnetic object has to alter either's signal only slightly to through the cancellation off. This provides higher sensitivity that a single sensing coil can provide.

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