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Problems with tantalum capacitor after leaving it on board for some time

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just_one69

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I have some bad experience with tantalum capacitor (tp)on board after leaving it for about a year or two:

1. While I'm trying to revive an old pc board, two of the tps exploded. I thought something wrong with the board.

2. I'm trying another board, samething happened.

3. While I'm trying to power up my home build variable power supply unit that I know it previously working nicely, samething happened.

4. Lastly, also on my home build power amp, something happened.

Any view or reference about the behaviour of tantalum capacitor.

Note: the thing happened only on equipment that you leave it for quite long time

Thanks in advance
 

cadb0y

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tantalum capacitor failure modes

tantalum capacitors good for years, you install correctly? they only install one way
 

J

just_one69

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tantal cap

All the boards and homebrew projects works nicely before retired for a couple of years.
(Not in use - not power up)

That what wonder me ...

Thanks anyway
 

dacadc

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tantalum failure mode

I have tested old Soviet Union caps 1969 old!!! It is works perfectly and have less lost event some modern tantal caps.
 

barrybear

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tantal capacitor

I have expereanced tantulun capacitors going short/leaky after time.Generaly down to the quolity of the capacitors.One tip is that the capacitor can sinter and if you slowly apply the voltage to the circuit and give the capacitor time to self heal somtimes you can breath life in to old caps.
Barrybear.
 

ms1234

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tantalum capacitor short circuit

Unlike the other capacitor, the tantalum capacitor failure mode is short circuit. With this charactor, it usually burned PCB to black color. For a used tantalum capacitor if you havn't used it for a long time it also turned to short ckt! That is why I don't like use tantalum capacitor.
 

pool_77

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tantalum capacitor lifetime

Process of creating Dielectrics of the electrolytic capacitors (Al2O3, Ti2O5)is reversible! It is created the first by a application of voltage about 2V. If the voltage will be increased and take longer, then the dielectric will be thicker and voltage rating will be higher and vice versa.

Info about leakage current you can fing for example:
wxw.avxcorp.com/docs/techinfo/soltant.pdf

pool_77
 

Pim

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tantalium capacitor

My experiences with tantal capacitors is the same as one of the
above posters, i.e. the thing that happen when they go defective is
that they behave as a very efficient short-circuits. If then there is
enough current capacity of the power applied to this
short-circuited defective tantal capacitor - you'll get a black
bad-smelling little piece left.

A few of the manufacturers of recent types of tantal capacitors
are though claiming that they have managed to come to terms with
this "normal" failure mode of their brand of tantal cap's. My advise
would be to search and investigate some of the manufacturer's
data-sheets regarding their most recent lines of tantal capacitors
and see which of them that claims that their capacitors do not go
into short-circuit as the normal failure mode.

Also, when there is any risk of the voltage being applied for some
moments with the wrong polarity to the capacitor, connect a diode
across it to bypass the current. Tantal cap's are, as I have noticed
by practise, very sensitive to the voltage being applied in the
wrong direction. You can also try to exchange some of the
tantal capacitors to high-capacitance ceramic types (they do have
a long life-time and no requirements on polarity).

/Pim
 

cadb0y

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tantalum capacitor polarity

good tip i try diode next time i use tantalum. i never see tantalum be bad so fast
 

hasan

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tantalum cap fire

I strongly recommend the tantalium capacitors on electronic board which working in noisely area, tantalium is best noise filter. But quality is important, they changes the value easily if they have not good quality. I had faced with short circiut affairs on tantalium capacitors. However they are still best filters i known.
 

Cathay

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lifetime tantalum capacitors

There are report of Cell phone caught fire
and trace down to Tan. Cap. short surge current. Epson has ban using of Tan. Cap.
in all their product in afraid of liability.

Of cause, there is also Political correct issue that 24% of Tantalum production in the
world is control by African war load that
sale the Tatalum ore for weapon.
 

darksky041257

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burnt tantalum capacitor

I have had caps fail.

Care has to be taken is tants are used across voltage rails- a fast voltage rise from a low
resistance can cause the cap to fail.
 

cadb0y

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ceramic capacitor failure modes

tant caps are only way to get high values with small space, use ferrite too for noisy
 

jmk69006

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tantalum capacitor burned

Hi,
I work in the power supply field.
We don't want to use tan. cap.
Because It's life is alway a problem.
If I need small size and high ripple curent rating capcitor, I will use OS-CON capcitor or multi-layer ceramic smd type capacitor.
 

J

just_one69

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failure modes of tantalum capacitors

Thanks for all the good responses

At least it can ease my feeling and take the necessary precautions next time
 

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