On Apr 29, 11:41 am, "Harold E. Johnson" wrote:
"K7ITM" wrote in message

...

It's easy enough to find the number of turns required for a particular
inductance on a known toroid core, but how do you know what size wire
to use so that the turns will all fit on a single layer? That's this
morning's geometry problem. I suppose you can find formulas, but a
quick Google search didn't turn up anything useful for me this
morning. What I worked out, that may be of some use to others, is:

Nice, but the software "Mini ring-core calculator" (ver 1.2 free) will do
this for you, as will the Amidon manuals.

W4ZCB

:-) I knew if I posted that, someone would tell me about a nice
little calculator. For others who may have trouble finding the mini
ring-core calculator, try: http://www.dl5swb.de/html/mini_ring_core_calculator.htm

I did find another somewhat similar calculator as a Java applet, but
it seems to get the wire size wrong. The one Harold mentions gets the
wire size right, and does a whole lot more. Great to have around if
you're winding toroids, and it also does simple solenoid coils and
inductance of straight wire. You can even select US units (AWG;
inches) or rest of the world units (metric). Nice that it also tells
you the length of wire you'll need to wind the coil. Includes a
resonance calc and more.

Thanks, Harold!

Cheers,
Tom