gEDA-user: bypass caps

[Stuart Brorson]

> What about Al electrolytics?  Like, for power supply bulk filtering?
> The furnace controller will be seeing 34 Vdc peak, does that mean 100v
> caps?

Yes, that's what I'd do.

Also, with electrolytics, you need to pay attention to the temp
rating.  85C rated caps are for cheap consumer junk.  You want at
least 105C for industrial equpt, IMO, and 125C is better if you don't
mind the cost and increased board real estate.  The lifetime of an
electrolytic cap depends exponentially upon the difference (rated temp
- operating temp), so using higher rated temps is a very good idea.

Nichicon has a long app note talking about electrolytic cap lifetime
issues.  Google for it, it's worth reading.  Also, a Google search
will turn up lots of info about how to properly select an electrolytic
cap.

Stuart