Yes. That is true. They are noisier. But for high voltage applications they are better because of the lower inductance. ----- Original Message ----- From: "Paul James E." To: Sent: Wednesday, February 08, 2006 9:46 PM Subject: Re: [EE] Carbon film vs Metal film resistors > > All, > > Another point of interest is in noise contribution. Carbon film > resistors inherently have a higher noise figure than metal film. > So if noise is an issue, don't use carbon film resistors. I believe > generally speaking, carbon film resistors have a noise value that is > typically twice that of metal film. And in most cases, it is three > to four times as high. Just food for thought. > > > Regards, > > Jim > > > >> 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. >> >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist > > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist