[AMPS] Non Inductive Resistors

Rich Measures measures@vc.net
Fri, 5 Sep 97 10:51:33 -0800


>I have been paging thru the new Newark catalog and came across a few
>interesting items that are "new" to me.
>
>Ohmite 50 and 100W non inductive resistors, including 50 Ohms. The caveat
>is that they give an inductance rating!  That would lead me to assume
>that they are not  HF RF rated but maybe for LF, audio and switcher
>supplies. Anyway the 50W is rated at  0.8uh and the 100W at 1.6uh.
>Has anyone experimented with these at HF, tuning out the XL, etc. ? The
>prices are a reasonable $9.19 and $16.81 respectively. 
>
There is no such thing as a non-inductive resistor.  The resistors we use 
in the suppressor retrofit kits (100 ohm, 3w Matsushita, MOF-type) have 
about 10nH - according to Wes, N7WS.  The longer the resistor, the more 
L.  A 100 ohm 100w globar-type has roughly 100nH [0.1uH].  At 28MHz, this 
amounts to only 17 ohms of X.  However, 1.6uH [1600nH] would be a bit 
much L, methinks. 

R. L. Measures, 805-386-3734, AG6K   


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