Tom Handley wrote:
>   Dan, Robert has provided a summary. It boils down to basic engineering.
>Know your environment and know the device characteristics. I have'nt had
>a Tantalum cap fail in decades. There is a good reason they are specified
>in vendor's application notes. If you use a 6V Tantalum in a 5V supply of
>questionable design, you are asking for trouble.
....


Tom, is it possible your circuits have all luckily fallen onto
the good side of the "border" that Robert was talking about?
Ie, power supplies with effective series impedance somewhat
larger than 1 ohm?

BTW, for another "rule of thumb", I was going to mention
that I measured the series R in a number of wall warts a
couple of years ago, and they were all pretty substantial,
10 ohm range or greater, for the smaller WWs.

For instance, the difference between Vopen_circuit and Vloaded
was generally 3-5v. Worst cases would be the larger WWs. Say,
[Voc-Vloaded]/Ioad = 3v/1A = 3 ohms, close to Robert's border.
Smaller WWs have higher R.

Cheers,
- Dan Michaels