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tantals in space

Bob Bruninga wrote:

> "If you build a small satellite transponder, someone might just fly it
> for you someday!  Just do it."
> use tantalum caps instead of electrolytics, then it is probably OK for space!

Tantalum capacitors are most dangerous if not handled with care and 
unreliable compared to electrolytics.  

All (large) capacitors in all P3 satellites were made of electrolytics 
with the ends additionally sealed by epoxy, this is no problem et all.

I also know a few companies which completely abandoned the use of tantalum caps
in their production line for good reason.

While Tantals are fine for many applications, they have a particular problem in 
power supplies and in fact many designers don't know that you have to have a 
current limiting resistor in series with the Tantal to limit the current when 
power supply is turned on etc..  The initial current can damage the Tantalum
cap and even produce catastrophic failures, like a shortage or so...

The worst thing which can happen to electrolytic caps is that it dries out
when the seal is broken.. But if you cover it with epoxy, this should not

73s Peter

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