[Test-Equipment] TM4520 inductors

[Brooke Clarke]

Hi Stewart:

The impedance of the coil is not all inductance, there's also some resistance 
and capacitance.   This means the apparent inductance will vary with frequency.
Impedance Measurements:
http://www.prc68.com/I/Z.shtml

Have Fun,

Brooke Clarke
http://www.prc68.com

Stewart Bryant wrote:
> Does anyone know the original purpose and
> rated frequency range for the Marconi TM4520
> inductor set?
> 
> The individual coils are marked TM1438/letter
> 
> I have been using then to compare a number
> of inductance meters with inconsistent results
> and wondered about the construction, frequency range
> and as they are in a nice polished box, whet their
> provenance was. (I picked them up for pence at
> a flea years ago because no one wanted them).
> 
> I note that they were used to calibrate the
> AADE inductance meter
> 
> http://www.aade.com/lcm2binst/HP.html
> 
> and that they are a museum piece,
> 
> http://www.porthcurno.org.uk/html/arc_result.asp?SearchText=1438&sType=any&recNo=0
> 
> but I wondered if anyone knew any more.
> 
> Stewart/G3YSX
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