>
>
> In Europe, small resistors are available in both carbon film (cheaper,
>> higher tolerance) and metal film (a little more expensive but also
>> closer tolerance). Medium power (1-3W) are almost exclusively metal
>> film, and in higher power ratings it's mostly conventional wirewound.
>>
>> The carbon film and metal film resistors up to 3W are available in all
>> values from 1 ohm to 1M. The same applies for other materials used in
>> "film" resistors, for example cermet or tantalum nitride but often not
>> specified.
>
>World-wide, there are now metal composition resistors available.
>
>They are off-the-shelf, inexpensive, temperature and life stable,
>handle very high overloads, and have virtually zero inductance.
? Every conductor in the known universe has inductance. Even
superconductors have inductance. A typical 3w, MO or MOF resistor has
>10nH. Terman covers this subject in his radio engineering book. Since L
varies logarithmicly with conductor width, a foot of #14 wire has
surprisingly [to me] little more L than a foot of 2" strap.
? For the curious, ground the grid of an 811A or 572B with a short piece
of wide copper strap. Measure the grid resonance with a dipmeter.
Remove the strap and replace it with a 50 - 200pF cap. Re-measure the
grid's resonant freq.
>I am
>evaluating samples now, and will beta test them in critical
>applications and report the results.
>
? Good
- R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
www.vcnet.com/measures.
end
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