Polypropylene versus metallized polypropylene

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Hi,
from reading, I think the advantages of metalised could be:- smaller package, less inductance, self repair.
And advantage of foil could be:- higher pulse current, higher dv/dt, ?

polypropylene and polystyrene are reputed to be audio suitable. Teflon might be but at the moment too expensive.

Wima's foil are not true foil, they incorporate metalised for self repair in the constructions they show on their website.

For bypassing, stick with ceramic for lowest inductance, but only with the very shortest of component leg lengths and close to the current client (glitch producer).

For decoupling, use polarised (electro/tantalum) of the biggest size that fit the board. Aim for a minimum of 20 times (preferably 1000 times) the total bypass on the board.
 
VS said:
Thank you, but thecnicaly speaking.....what is the diference? Are the dissipation losses smaler? Is the dielectric absortion ?

Regards,
VS

Metal foils show usually lower distortion than metallized. Cyril Bateman was suspecting non-ohmic contacs along the metallization and end plates to be a cause of this. I recommend C. Batemans series of articles in Electronics World(Capacitor sound parts 1&2&3&4&5...) if you are more intrested on subject.
 
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