[RFI] New Larger Fair-Rite #31 Toroid
jim at audiosystemsgroup.com
Fri Apr 14 14:33:13 EDT 2017
On Fri,4/14/2017 10:26 AM, Dave Cole wrote:
> A question for you... Looking at the "Impedance vs. Frequency vs.
> Turn count" graph at:
> It looks like these new cores only have two or three K of impedance
> with five turns... Am I interpreting this correctly?
> If so, then using two of them with five turns becomes the standard if
> I want more than five K impedance? Is that true?
The number of turns (and to to the extent that it affects capacitance,
wire size and spacing) sets the resonant frequency. The Fair-Rite data
is most likely for small diameter wire. If you want the choke to be
effective where 5 turns puts it, yes, two chokes in series would be the
way to get there. A choke wound with RG8/11 size coax would have the
same inductance but more capacitance between windings if those windings
are closely spaced, so the resonance would be a bit lower.
And, of course, more turns will lower the resonance even more, and
because R also increases with N-squared, also raise the impedance.
73, Jim K9YC
> 73s and thanks,
> On 04/14/2017 09:53 AM, Jim Brown wrote:
>> Yesterday, I got a quote on this part from Dexter, a vendor that has
>> been competitive for past orders. They don't have stock, minimum order
>> is a full box, which is 25 pieces, $15.18 each. 50 pieces is $14.27
>> (-6%). 100 pieces is $13.57. Delivery was quoted as 14 weeks.
>> 73, Jim K9YC
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