Magnetic fields within a toroid inductor.

[Magluvin]

http://www.nktechnologies.com/current-sensing.html

http://www.sensorsmag.com/sensors/electric-magnetic/measuring-current-with-imc-hall-effect-technology-786

http://www.scienceshareware.com/how-to-measure-AC-DC-current-with-a-hall-effect-clamp-.htm


Mags

[Magluvin]

So that must be how a clamp amp meter measures DC current.


Mags

[Magluvin]

Here is a pic of a cool field viewer. This could be done with a toroid. Piece of plexi with a hole for the outer diameter of the toroid and a small circle piece for the toroid hole.  It would be interesting to see if iron filings do anything around the toroid.

Mags

[Newton007]

I think the magnetic field would be stronger on top of the plexiglass than on the bottom.but that is just a guess.

[poynt99]

So that must be how a clamp amp meter measures DC current.


Mags

And AC current.    60Hz is no problem for many Hall sensors.