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19th April 2004, 05:58 PM
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#1 |
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diyAudio Member
Join Date: May 2003
Location: Arnhem
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Film cap's
Can anyone tell me what is meant by film capacitors? They are suggested for audio applications.
Are any of the following types film caps and are they suitable for audio applications? Orange Drops - Polypropyle Silver Mica Mallory (non-inductive) Regards Henk Koetzier |
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19th April 2004, 08:45 PM
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#2 |
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diyAudio Moderator Emeritus
Join Date: Jan 2003
Location: Near London. UK
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Film capacitors use a plastic film as the dielectric (insulator) between the (conductive) plates of a capacitor. Plastics used are; polytetrafluorethylene, polystyrene, polypropylene, polycarbonate, and polyteraphylate (polyester).
Silvered mica uses naturally occurring cleaved sheets of mica as the dielectric. Because mica is a natural material, it is variable quality. In general, silvered mica is not quite as good as polystyrene. Those Mallorys are probably electrolytic. Some audio uses require electrolytics. Search the forum and you will find lots of information...
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The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference... |
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19th April 2004, 09:00 PM
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#3 |
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diyAudio Moderator
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You caused great pain to my Inner Polymer Chemist. It's "polyethyleneterphthalate" or "PET" or "polyester." Trade name "Mylar" when it's sourced from DuPont.
Another popular dielectric these days is polyphenylene sulfide (PPS), which has excellent performance at high temperatures.
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19th April 2004, 09:44 PM
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#4 | |
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diyAudio Moderator Emeritus
Join Date: Jan 2003
Location: Near London. UK
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The quick brown fox...
Quote:
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The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference... |
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19th April 2004, 10:17 PM
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#5 |
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diyAudio Moderator
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That's why we say, "PET," a much more euphonious appellation. The naming of copolymers is fraught with peril; today I placed an order for poly(styrene-isobutylene-butadiene-styrene), which is difficult to say ten times quickly.
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If there's a sucker born every minute, where do the rest of them come from? |
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20th April 2004, 02:41 AM
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#6 | |
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diyAudio Member
Join Date: Mar 2003
Location: Indiana, USA
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Quote:
... and what exactly is this used for?
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Dawn: When men of reason go to bed. ~Ambrose Bierce |
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20th April 2004, 04:18 AM
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#7 | |
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diyAudio Moderator
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Quote:
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