I have a reed switch that shows a 10AT to 15AT operate range on the data sheet. I need to determine if specific magnets will fire the switch, and at what distance.

The magnets I'm looking at though, of course do not have any kind of AT units. Their data sheets provide a Flux Density (in G), Maximum Energy Product (in kJ/m3) or Pull Rating (in lbs/ft).

I've searched all kinds of conversion formulas but end up with a guess at best. What is the proper way to know if a magnet will trigger the switch at specific distances (say 1 inch, 1/8", etc)? (without of course buying the magnets and testing them all)

Unfortunately, the tech support for the national reed switch manufacturer is terribly unresponsive.

  • \$\begingroup\$ Ampere-turn or AT is the SI unit of magneto-motive force and is a direct measure of a reed contact's magnetic sensitivity. The equivalent CGS system unit is Gilbert, and 1 Ampere-turn = 4π/10 or 1.256 Gilberts. AT is also denoted as NI which denotes the product of the number of turns in the test coil N and the current I. \$\endgroup\$ – vicatcu Oct 21 '19 at 1:48

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