Re: Choke sources

Hi Keith,
           Re your second query: the easiest way to calculate turns 
for a required inductance is to use the manufacturer's published 
induction factor (Al) for the core. You can determine this for 
yourself by winding say ten turns on the core and measuring the 
inductance (e.g. LCR meter, resonate with known cap etc.). Al is 
expressed as nH/turn^2 by some core manufacturers.

turns = SQRT(L/Al)  or L = Al*N^2


> Original Poster: Keith Garvin <keithg-at-datalight-dot-com> 
> Hello everyone!
> Can anyone point out where some 3" - 4"
> ferrite toroid or cylinders can be obtained
> from?
> My current setup includes only some small
> forms from radio shack.  When powering the
> system up and down I can watch an arc between
> the form and wires on all the coils.
> If anyone has the formulas for calculating
> the inductance on a toriod and/or ferrite cylinder
> that also would be apprecited.
> Many thanks in advance!
> Keith