Tantalum capacitors

[eccerr0r]

How have people been dealing with tantalum capacitors?
Replace on sight, due to their "Sudden Death Syndrome" or "Leave unless dead" (ESR too high?)

Supposedly they too have lifetimes but haven't seen much information about how long they should last. And some conflicting reports, some tantalums are liquid electrolyte and last longer than some solid electrolyte tantalums?

What gives?

[stj]

Re: Tantalum capacitors

i work on space invaders machines made in 1979, and sometimes older stuff from 76'
37 years and the tants are still good.

in my experience they only fail by shorting out - ending with smoke flames.
and that is caused by reverse polarity spikes.
(something they should never be exposed to.)

the latest tants come in a version that is designed to fail open-circuit for added safety btw, so i dont expect to see anything modern incinerate itself.

[stj]

Re: Tantalum capacitors

btw, i salvage SMD ones and re-use them to replace small electrolytics in low voltage circuits.

[eccerr0r]

Re: Tantalum capacitors

Interesting. I saw a (yet another will-not-mention because of search engine linking) article indicating tantalums have a lifetime too but I would agree, seems most solid tantalums should last virtually forever.

I was wondering about my early '80s 'scope which is full of tantalum capacitors. I think only the bulk filter capacitor is one of the few electrolytic caps which probably should be replaced someday...

--

Incidentally someone at a hamfest threw out a bag of hundreds of SMD 6.8uF 10V and 15uF 10V tantalum caps. I grabbed it just in case, I suspect they're not very useful as they're not on tape.

[stj]

Re: Tantalum capacitors

great find!!
you can use them on logic circuits (5v, 3.3v) the size often is exactly right to bridge across the pads for a through-hole electrolytic.

[Alwyn]

Re: Tantalum capacitors

I'm little worried because I'm not sure whether it is a right thread to ask question or not. Question is, How good or bad tantalum capacitors as compare to other capacitors like Series, variable? Here https://www.derf.com/how-tantalum-capacitors-work/ I found overview and their construction but it is difficult to understand the comparison with others. Can anyone throw some light on it?

[stj]

Re: Tantalum capacitors

i'm not sure what your asking.

tants have lower esr than electrolytics,
they are smaller,
they dont dry up.

the only downsides is you cant get them over 35v,
you need to use atleast double the voltage you intend to put in them,
you must never hit them with large spikes or AC / reverse voltage - or they burn up.

electrolytics also dont like reverse voltage though - so really it's mostly a cost thing.