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Learning About Toroids

Jan 3rd 2013, 16:04

dneale

Joined: Jan 4th 2012, 19:26
Total Topics: 0
Total Posts: 0
Hi,

As a new Extra I'm considering building some QRP CW gear. I have been building non-RF gear for many years. In the QST articles there are many different toroids used in the various designs.

I haven't found a resource that helps me understand the nomenclature used for the various ferrite/iron cores in different designs. Is there a reference that would help me understand what the various core designators mean? I looked at the Fair-Rite web site and see one of the numbers apparently indicates permeability. Are those numbers consistent across manufacturers? Is the other number size and if so how do they relate to dimensions? What do the letters FT, T, FB, mean?

Thanks,

Dave
Jan 3rd 2013, 16:51

W1VT

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0

I'd suggest the Component Data and References chapter of a recent ARRL Handbook. Information on toroids has been in the ARRL Handbook for decades, but the Handbook has been reorganized over the years, as there are technologies used today that hams didn't know about in the 1970s.

T refers to (iron powder) toroid
FT refers to ferrite toroid
FB refer s to ferrite bead

You may also find these web pages useful
http://palomar-engineers.com/toroid-cross-reference

http://kambing.ui.ac.id/onnopurbo/orari-diklat/teknik/balun/Ferrite%20Toroid%20Core%20Size%20Cross%20Reference.htm
This may be useful for deciphering parts used on the other side of the Atlantic

Zack Lau W1VT
ARRL Senior Lab Engineer
Jan 3rd 2013, 19:17

dneale

Joined: Jan 4th 2012, 19:26
Total Topics: 0
Total Posts: 0
Zack,

Thanks so much. Looks like everything I need is in the Handbook. My library is growing faster than I can assimilate it!

73,

Dave
Oct 23rd 2013, 12:17

K3CB

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Send me your email and I'll send you a much better tutorial on toroids than what's in the Handbook.. Owen, K3CB k3cb@earthlink.net

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