On Wed, 23 Sep 2015 11:58:43 -0700, Jeff Liebermann wrote:

On Tue, 22 Sep 2015 19:02:33 -0700, John Larkin

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I know for sure that tantalums sometimes blow up at below their rated
voltages, with no overshoot spikes. It's dV/dT, namely peak current,
that can ignite tiny particles of tantalum, which then burn in the solid
MnO2 electrolyte.

I think you mean dI/dT which provides the heating necessary to ignite
the tantalum. That all sounds logical, but doesn't explain why a
similar amount of heating caused by normal ripple current doesn't set
fire to the capacitor. I've seen some heat darkened tantalums operating
normally without ignition. Like the bulging electrolytics and burning
LiIon batteries, I suspect there's been some changes in production
methods (like skipping important steps to save pennies).

Are you sure? I understood that the I=C.dV/dt was responsible for the
damage. The higher dV/dt, the higher I. And the longer the dV/dt
continues, the hotter the C gets.

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joe