[R-390] Cap Voltage

[Charles Steinmetz]

Roger wrote:

>There was once thread on AC caps and how much DC voltage could be 
>used on them in a power supply.
>If my cap is marked 400VCA 20UF how much DC can I apply to the cap 
>if I use it as a filter cap in a DC power supply and want it to last?

Much, much less than 400V, but I'm not aware of any generalized 
conversion factor.  It all depends on the particular cap design.  I 
once put this question to a Sprague capacitor engineer, and he looked 
at me cockeyed and said, "Don't ever put DC on AC-rated 
caps.  They're not designed for it.  We make DC-rated caps for that."

Best regards,

Charles