[AMPS] Non-inductive resistors

[Ian White, G3SEK]

Tom Rauch wrote:
>I just received sample 5 watt metal film  resistors from Mouser, as 
>per the conversation with Carl.
>
>The measured inductance of two 51 ohm resistors with nearly zero lead 
>length was 47.1 nH and 49.3 nH. 
>Both resistors are wound with about a five turn spiral of metal film 
>inside the case. 

Guessing at the length and diameter of a 5W resistor and using Tom's
estiamte of "about five" turns, the usual formula for the inductance of
a solenoid gives results somewhere in the right area. I wonder how well
it works with the actual dimensions?

Could you run a ruler over the resistors, Tom, and give us a better
estimate of the actual number of turns?

73 from Ian G3SEK          Editor, 'The VHF/UHF DX Book'
                          'In Practice' columnist for RadCom (RSGB)
                           http://www.ifwtech.demon.co.uk/g3sek

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