Chris,
Here are some things about toroids.
1. Everybody tells you to count the turns as you go through the toroid,
but nobody ever tells you how to check it afterwards. Once you've
wound, count the number of turns on the inside of the ring and you can
verify the number to make sure it's right.
2. There's two ways to wind them and they "wind up" being mirror
images. Sometimes it doesn't matter, but usually you have to do it the
right way or else it won't line up with the holes. Start out either
left on top or right on top, and keep it that way. Once you've wound it
and it doesn't fit the board, flipping the toroid itself over won't help.
3. Pay careful attention to getting the enamel insulation off the ends
of the wire, up to and just past the point where the wire goes into the
board. Any insulation that touches the PC board is a recipe for
trouble. Don't wear shorts when you're tinning the leads. (Not that I
have any experience with that...)
4. If there are pictures, make the toroid windings look like the
pictures. If not, make it take up 80% of the core. See also #2 if
there are pictures.
5. Always double and triple check to make sure none of the windings
cross over each other or get "knotted" up. (Remember in Ghostbusters
when they said, "Never cross the streams!" They didn't say why, but my
guess is that it has to do with flux linkages.)
6. And finally, if you want to eliminate that asymmetric wire, you can
run center the wire in the toroid before winding by holding both ends of
the wire, making it into a U and, and dangling the toroid from the
center of the wire like a necklace or a charm bracelet. Then wind back
both ways, (N-1)/2 turns. The wire will always come out centered.
Unfortunately, you have to think harder to deal with #2 if you do this,
because everything winds up backwards from how you start. Obviously this
works out best for odd-numbered turns counts. For even counts of turns,
give one side an extra turn and start it out longer by 1/2" for T30 and
1" for T50.
73 es GL,
Leigh/WA5ZNU
Hi all,
I'm at the point with my KX1 build to wind my first
torroid and I have a question.
In the man it says to cut 13" of red wire, after
winding 14 turns on a yellow core, I still have a lot
of extra wire.
Almost 2" on one side and about 4.5" on the other.
Is this the norm?
Just want to make sure things are right before I trim
and tin.
Thanks
-chris
_______________________________________________
Elecraft mailing list
Post to: [email protected]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
