GMR sensors and inductors for detection of metal / magnetic fields

[[email protected]]

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

 

[John Popelish]

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?

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.