[Amps] Need some 220K 2 watt carbon resistors

[Ian White GM3SEK]

Gary Smith wrote:
>How can one see/read/find out as to how low the inductance of a 
>particular resistor might be? Am not trying to open a can of worms 
>here, am well aware that as a resistor heats up its inductance changes, 
>but... ?  Larger wattage values= less inductance to what might be 
>referred to as the "point of diminishing returns?" No flaming please, 
>yes, I should know the answer to this one but I do not.
>That is why I am asking.

Scrape off enough of the paint/cement/enamel to be able to count the 
number of turns (n). Measure the diameter (d) and length (b), and then 
plug the numbers into the usual formula:

L = d^2*n^2/(18*d + 40+b)   uH (inch units)

It would need a vector network analyser, used with some care, to measure 
the inductance more accurately than you can calculate it.


-- 
73 from Ian GM3SEK         'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek