Amidon re-sells Fair-Rite cores.? It is an "unauthorized" distributor.? They copy the material designation (EG, 31) but have their own numbering system for the shape.
However, Fair-Rite's material designations are not applicable to other manufacturers.
Fair-Rite DOES sell toroids in 31 material, but in that material they
are called "Round Cable EMI Suppression Cores".
Yes, this is confusing.? But it is what it is.
Regarding pricing:? the best pricing is from Fair-Rite authorized distributors, which sell to businesses.? The "hobby" sellers like Amidon are MUCH more expensive.
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On 2022-01-13 11:16, Tomasz Lemiech wrote:
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Hi,
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You guys often use terms like FTxxx-yy or BNxxx-yy to refer to various ferrite products - like "use x turns on a FT240-31 for this application". By that, do you have any particular manufacturer / brand / product number in mind? Or do you mean that any product of 2.4" diameter made of 31 material will do, even when it's a no-name brand?
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I guess this scheme might have come from Amidon's product lineup, which seems to use these markings (). That would make sense. But then I see things like which is allegedly made by Fair-Rite. However "FT240-31" string is nowhere to be found on their webpage - they have their own numbering scheme. What's more, according to they don't make toroids out of 31.
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Another thing is mix type numbers. For some reason, Amidon's numbers seem to coincide with Fair-Rite's. Is there any standard or industrial norm that these numbers come from? Is it safe to assume that, for example, a toroid made of 31 is mostly the same thing performance-wise, regardless of the brand stamped on the product?
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Apparently Amidon has FT240-31 in their product line () but there is no specs for this mix on their page (). But they are currently updating it, so fingers crossed! ;-)
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Have you encountered any gotchas during your prior purchases? Like two toroids with the same FT or BN number from two different brands, having completely different characteristics?
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Regards,
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