[RFI] toroid core color coding

[Pete Smith]

I just pulled 4 toroid cores out of a defunct surplus computer power supply 
(110v in, 5 and 12 volts out).  The cores are 1" to 1.375" OD, and a little 
under .5 inches high.  One is solid yellow, two are green on the outside 
and yellow on the sides, while one is yellow on the outside and white on 
the sides.  Is there an industry standard anywhere on these color codes 
that anyone can point me to?  I think I saw an e-mail on this a few years 
ago but can't find it now.

Otherwise, can someone who knows more about such supplies opine as to what 
frequency range they are likely good for?  One was bifilar wound with 
~#24-26 twisted pair, while the others are single windings of 1-2 layers of 
enameled wire.  The latter are the ones that are green with yellow sides, 
while the bifilar winding was all-yellow.

73, Pete N4ZR
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