[R-390] Caps

[Charles P. Steinmetz]

Dave wrote:

>How about the Panasonic Polypropylene like these

They are metallized film (see upper left corner of the datasheet), 
and suffer from the same self-healing behavior that plagues all 
metallized film caps.  If you get the full engineering information on 
them, Panasonic (like all manufacturers of metallized film caps) is 
very up-front about it.  They just didn't put it on the abbreviated datasheet.

Barry wrote:

>I may be wrong, but I think all metallized film caps are self-healing.

Correct.  At least, all commercially-available metallized film 
caps.  In principle, if one used film as thick as is used in 
film-and-foil caps, it might go a long way toward mitigating the 
problem (there would still be the issue of the vapor deposition of 
the metallization, which is hard on the film).  But nobody does, at 
least not in their general capacitor lines.

Best regards,

Charles