On Wed, 26 Nov 1997 20:15:02 EST, km1h@juno.com (km1h @ juno.com)
wrote:
>
>On Thu, 27 Nov 1997 00:03:54 GMT wrt@eskimo.com (Bill Turner) writes:
>>On Tue, 25 Nov 1997 16:08:08 EST, km1h@juno.com (km1h @ juno.com)
>>wrote:
>><snip>
>>
>>>
>>>IMO, the 2W carbon will quickly become obsolete.
>>>
>>_______________________________________________________________
>>Quicker than you think. Allen-Bradley is (make that was) the only
>>manufacturer of high-quality carbon comp resistors (MIL-SPEC
>>certified), and they announced last year they were quitting the
>>business. My company has had to change thousands of bills of
>>materials over to metal-film or metal-oxide types. A major expense.
>>
>>If you need carbon comp resistors, better stock up now.
>>
>>73, Bill W7TI
>
>
>I wonder how that will affect the military replacement procurement Bill?
>Will us taxpayers now have to fund $600 carbons to go along with the
>toilet seats?
>
>73 Carl KM1H
_______________________________________________________________
Nope, unless some other company starts up production, carbon comps
won't be available at any price. The major expense is not the cost of
the parts, but in revising bills of material and all the paperwork
that entails. In a way, I'm glad to see the change come. Metal film
and metal oxide are much more stable than carbon comps. Their only
serious drawback is they don't handle short term power spikes as well
because the resistance element is not as large, physically. In almost
all other respects, they are better. Inductance could be a problem in
some applications because the resistance element is often spiral-cut
for trimming purposes.
One possibility which might be worth investigating is surface mount
resistors. They are becoming available in higher-wattage packages and
could be easily soldered end-to-end or paralleled with very low
inductance resulting.
73, Bill W7TI
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