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									                      sci.electronics.components: Re: Amidon toroids, color code

                     Re: Amidon toroids, color code


From: Watson A.Name − \ (
Date: 02/05/05

Date: Sat, 5 Feb 2005 02:31:49 −0800

"Dave Platt" <> wrote in message
> >Yes, for amidon toroids I mean generic toroids with two color band;
> >really disappointed to know that there is no standard color coding,
> >seems that no−amidon is almost useless if I don't know the producer
> It's possible that you're seeing manufacturer−to−manufacturer
> variations in standard codes, or you're seeing codes that were
> specific to particular batches of toroids made for a particular
> customer (the equivalent of "house numbers" on integrated circuits).
> Best idea I can offer, is that you actually measure one or two toroids
> of each size and color code. The olde−standard method should work
> just fine − wind a toroid with a few turns of wire, leave an inch or
> two of leads at the end, tack−solder a high−quality cap of known value
> to the ends, and measure the resonant frequency with a grid−dip meter.
> Alternatively, use an AADE or HP 130 or similar sort of inductance
> meter.

It's a lot harder to measure a toroid with a dipmeter because the
magnetic field is so well contained inside the toroid. Might be a good
idea to leave enough lead to make a turn so you can couple the
dipmeter's coil to it.

> This will tell you the inductance of the winding you put on, which
> will let you calculate A(l), which will give you a reasonable chance
> of figuring out what the iron or ferrite mix happens to be.
> To refine things further you could stick the same wound−up toroid on a
> Q meter, and measure the Q at various frequencies.

Toroids are usually very high Q.

> −−

Re: Amidon toroids, color code                                                             1
                    sci.electronics.components: Re: Amidon toroids, color code
> Dave Platt <>
> Hosting the Jade Warrior home page:−warrior

Re: Amidon toroids, color code                                                   2

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