EMRFD Message Archive 6627
Message Date From Subject 6627 2011-09-10 11:39:41 dnorbury Toroid identification I got hold of a bunch of toroids of three different sizes. I've looked at the catalogs of the major suppliers (Amidon, Fair Rite, Micrometals, etc.) but can't find the sizes listed that match mine. They are yellow/clear in color and the dimensions are:
1. OD = .500, ID = .290 and HT = .260.
2. OD = .805, ID = .480 and HT = .270. (close to T80-6?)
3. OD = 1.065, ID = .555 and HT = .320.
Any idea of the manufacturer and part numbers? If I can't find this out I will just wind some turns on each and figure out the approximate specs but it would be nicer to get the complete set of data from the manufacturer.
Thanks for your help,
6629 2011-09-10 13:44:14 Leon Heller Re: Toroid identification 6630 2011-09-10 14:21:49 dnorbury Re: Toroid identification Leon,
You're right, of course. I am hoping that the sizes of the toroids would help identify the (likely) manufacturer and part numbers and therefore the specs. I could then verify them with a sample winding and inductance measurement.
6631 2011-09-10 15:35:48 Andy Re: Toroid identification It might not be true, but I've heard it said that Fair-Rite makes most
ferrite toroids, and companies like Amidon are mainly re-sellers.
Micrometals might be another manufacturer.
I've also seen it said that the materials are color-coded, but this
might not apply to all vendors equally.
That being said, I'm afraid I'm not much help.
W8DIZ's Kitsandparts website gives the colors and sizes of the ones he
sells. For the Micrometals cores, the listed color codes are:
These are not the Fair-Rite mixes (43, 61, etc.), which seem to be
various shades of black.
6634 2011-09-11 00:26:48 John Kolb Re: Toroid identification Dave, color yellow/clear - did you mean the cores are Yellow on the
painted sides and dark gray
on the unpainted side. I have a sample bag of Microsoft T50-26B
toroids which measure
about 0.505 OD, 0.290 ID, and 0.260 HT, and would match your
dimensions. These are Yellow
on three sides and white on the bottom.
The"B" in the part number indicates an alternate height. A T50-26
without the "B" would be 0.190 HT,
If Micrometals made a T50-6B (yellow/clear), it would probably have
the dimensions you measure,
but can't find one using their search function in their
catalog. Could have been a special product.
There's a T51-6B http://www.micrometals.com/rfparts/rftoroid3.html
but the ID and HT don't match.
Note that Micrometals yellow/clear cores I've seen are typically well
painted on the top but OD and ID edges
tend to be splattered rather thinly.
I've also seen yellow/white cores in switching power supplies, and
believe these to be ferrite rather
than the powered iron of Micrometals cores.
At 11:39 AM 9/10/2011, Dave wrote:
>I got hold of a bunch of toroids of three different sizes. I'veAt 03:35 PM 9/10/2011, Andy wrote:
>looked at the catalogs of the major suppliers (Amidon, Fair Rite,
>Micrometals, etc.) but can't find the sizes listed that match mine.
>They are yellow/clear in color and the dimensions are:
>1. OD = .500, ID = .290 and HT = .260.
>2. OD = .805, ID = .480 and HT = .270. (close to T80-6?)
>3. OD = 1.065, ID = .555 and HT = .320.
>It might not be true, but I've heard it said that Fair-Rite makes most
>ferrite toroids, and companies like Amidon are mainly re-sellers.
>Micrometals might be another manufacturer.
>I've also seen it said that the materials are color-coded, but this
>might not apply to all vendors equally.
>That being said, I'm afraid I'm not much help.
>W8DIZ's Kitsandparts website gives the colors and sizes of the ones he
>sells. For the Micrometals cores, the listed color codes are:
>These are not the Fair-Rite mixes (43, 61, etc.), which seem to be
>various shades of black.
>Yahoo! Groups Links
6635 2011-09-11 05:14:46 dnorbury Re: Toroid identification John,
I think you got it. I was calling the colors yellow/white assuming the white was to be interpreted as "clear" since I saw no yellow/white listed under the RF toroid list. My mistake for not checking the power toroid listing! From that list it appears that the three are T50-26B, T80-26 and T106-26A. I guess now I'm into switching power supplies rather than RF!
Thanks for the help,
6637 2011-09-11 10:02:19 Ashhar Farhan Re: Toroid identification Wind 20 turns on the and plug it into a oscillator with known
capacitance. Measure the frequency and back calculate the inductance
and divide it by 400 to get inductance per turn squared. That's the
main thing you need to know.
You will also want to know the Q. A simple jig with two capacitors
and a signal generator will give you that measure (refer to emrfd's
test meaurements chapter).
I have used nylon tap washers, brass rings and even air core toroids
with this technique. A little bit of measurements will take you a long
way in classifying your collection of toroids and other RF coils.
6638 2011-09-11 11:29:09 William Carver Re: Toroid identification In my experience YELLOW-WHITE cores are -26 material. They are powdered
iron, but are high permeability used for switching and AC powerline
YELLOW, clear on the bottom, have always been -6 material. Highest Q
material over 5-15 MHz.