[Elecraft] K2 Toroids not measuring correct inductance?

[Jack Smith]

I recently measured, using lab  grade equipment, 16 powdered iron toroid 
inductors of approximately 2uH and 16 of approximately 9 uH, at a fixed 
frequency. Details can be seen at 
http://www.cliftonlaboratories.com/may_2011.htm under 15 May 2011 entry.

The purpose of the exercise was to assess the inductor-to-inductor 
variation, recognizing that 16 inductors, wound by the same person, and 
from one batch of cores, is likely to show less variation than if 16 
different builders wound one inductor each, and if the cores were from 
random manufacturing batches.

The inductance spread was 10% for the 2uH parts and 8% for the 9uH parts.

Jack K8ZOA


On 6/1/2011 1:25 PM, Eric Swartz - WA6HHQ, Elecraft wrote:
> Stick with the correct number of turns. The inductance listed is a
> nominal calculated value and will vary from core to core, and with the
> frequency used to measure the inductance.
>
> We also see a wide variance in inductance measurements between different
> instruments based on their differing test frequencies.
>
> It -is- important that you confirm you are using the correct core, color
> etc.
>
> 73, Eric
>
>
> On 6/1/2011 10:20 AM, rhapak wrote:
>> Hi all!
>> In the K2 manual it says to wind the toroids with the amount of turns
>> specified and not to alter the windings to get the inductance specified in
>> the parts list.
>> I notice that many of my toroids do not measure near the stated inductance
>> in the parts list but are wound with the specified amount of turns and would
>> just like to know why??
>>
>> Thanks in advance,
>> Rod
>> VA3 ZVT
>>
>> --
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>> Sent from the Elecraft mailing list archive at Nabble.com.
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