I'm skeptical that the carbon film scheme will reliably dissipate the 
heat without changing
value considerably. 

The Chinese have an enormous problem here in the colonies- many 
companies have pulled
back their plastics molds (if the chinese will give them back) due to 
unethical business
practices on several levels.

Before I would change, I would run a bunch of tests.

--Bob 

Russell McMahon wrote:

>I have grown so accustomed to using metal film resistors for 
>'everyday' applications that carbon film doesn't usually feature in my 
>thinking.
>
>A Taiwanese manufacturer has asked whether they can substitute carbon 
>film for metal film in a design. They claim that cf costs are far 
>lower. Volumes are only moderate (1,000 - 10,000 products per year at 
>most). Most resistors are operated at far below their power and 
>voltage ratings.
>
>My initial reaction is that whereas most resistors could technically 
>be changed to CF, the cost savings would be minimal compared to other 
>costs and that sacrificing the reliability of metal film would not be 
>worthwhile. I'm also dubious about the merits of allowing CF as they 
>would almost certainly be Chinese* sourced with unknown (indeed 
>non-existent) provenance and aimed at bottom of the market, 
>quality-irrelevant applications. (I've little doubt that there is a 
>reason that they are cheap).
>
>Thoughts? - or recent experiences with modern CF resistors.
>Am I too prejudiced against a new 'mature' technology?
>
>
>
>        Russell McMahon
>
>* I've no doubt that when it makes sense to do so China can produce 
>products of superb quality. But I also have little doubt that the 
>burgeoning market / what the market will bear / caveat emptor / take 
>no thought for the morrow ... / aspects of the present market 
>explosion mean that quality will often be, at best, only as good as it 
>has to be. 
>
>  
>


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