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Old February 9th 20, 07:33 PM posted to uk.d-i-y
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Default Why doesn't everything use solid aluminium capacitors?

On Sun, 09 Feb 2020 16:43:30 -0000, alan_m wrote:

On 09/02/2020 16:06, Brian Gaff (Sofa 2) wrote:
Stop excessive crosposting...

I suppose cos they can get them el chepo. I also have found toward the end
of the 90s, those little tantalum caps that look like blobs of resin
coloured blue tend to go leaky and damage the rest of the circuit.
Nothing is supposed to last any more.
Brian


I remember working on (expensive) test equipment in the 80s and a common
failure mechanism with the tantalum bead capacitors was a short circuit
taking out other components.


Were those visibly obviously damaged? It's just I've never seen one fail, and was wondering if I could tell from a visual inspection. The electrolytics have clearly failed when they bulge or burst - I see it all the time in old/cheap motherboards, or inside TVs.

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Old February 9th 20, 09:59 PM posted to uk.d-i-y,alt.home.repair,alt.comp.os.windows-10
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Default Why doesn't everything use solid aluminium capacitors?

Commander Kinsey wrote:
What's wrong with crossposting? There are 4 groups where people might
know the answer. Yes, I could post 4 times seperately, but then people
wouldn't see each other's replies.

I've checked both Ebay and Alibaba (where you can buy huge bulk
quantities), and the prices are no different.

I've never seen the tantalum ones break.


On Sun, 09 Feb 2020 16:06:41 -0000, Brian Gaff (Sofa 2)
wrote:


Stop excessive crosposting...

I suppose cos they can get them el chepo. I also have found toward
the end
of the 90s, those little tantalum caps that look like blobs of resin
coloured blue tend to go leaky and damage the rest of the circuit.
Nothing is supposed to last any more.
Brian


This is copied from the web page of a capacitor company.

Pros of aluminum electrolytic capacitors:

Higher voltage ratings available (up to 600V)
Way cheaper pricing (for the same capacitance and voltage)
Better leakage current behavior than polymer

Pros of polymer electrolytic capacitors:

Lower ESR/higher allowable ripple current
No dry-out behavior (unlike aluminum capacitors)
Higher expected lifetime/load life

And while one biased company claims electrolytics
dry out after 3 years (a made up number), another
company (likely using field statistics for their
own capacitors) finds the time constant is 17 years.
And I would have to conclude that the 17 year number
is likely to be closer to the truth (based on old computers
still in a running state, like my first computer from
1998-1999 or so which still operates just fine).

The Arrhenius effect is for real, and operating even
the best electrolytics at high temperature, doesn't
end well. At the highest allowed temperatures, some
of these electrolytics (by calculation) should only
last for 2000 hours. That's what the curve fit data
for accelerated life testing shows. When I say a
number like 17 years, it would be in an item with
proper and copious cooling. Note that electrolytics
themselves get warm in service, depending on the
ripple current being forced through them. The plastic
sleeve on the outside, does not enhance cooling for
those situations. The capacitors in VCore (on the primary
or secondary side) could be experiencing high ripple currents.
And if any are to fail, those should go first. The
"bulk" decouplers placed near a PCI or PCIe slot,
those aren't under nearly the same stress level.

HTH,
Paul
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Old February 9th 20, 10:06 PM posted to uk.d-i-y,alt.home.repair,alt.comp.os.windows-10,alt.computer.workshop
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Default Why doesn't everything use solid aluminium capacitors?

On Sun, 09 Feb 2020 20:59:20 -0000, Paul wrote:

Commander Kinsey wrote:
What's wrong with crossposting? There are 4 groups where people might
know the answer. Yes, I could post 4 times seperately, but then people
wouldn't see each other's replies.

I've checked both Ebay and Alibaba (where you can buy huge bulk
quantities), and the prices are no different.

I've never seen the tantalum ones break.


On Sun, 09 Feb 2020 16:06:41 -0000, Brian Gaff (Sofa 2)
wrote:


Stop excessive crosposting...

I suppose cos they can get them el chepo. I also have found toward
the end
of the 90s, those little tantalum caps that look like blobs of resin
coloured blue tend to go leaky and damage the rest of the circuit.
Nothing is supposed to last any more.
Brian


This is copied from the web page of a capacitor company.

Pros of aluminum electrolytic capacitors:

Higher voltage ratings available (up to 600V)
Way cheaper pricing (for the same capacitance and voltage)
Better leakage current behavior than polymer

Pros of polymer electrolytic capacitors:

Lower ESR/higher allowable ripple current
No dry-out behavior (unlike aluminum capacitors)
Higher expected lifetime/load life

And while one biased company claims electrolytics
dry out after 3 years (a made up number), another
company (likely using field statistics for their
own capacitors) finds the time constant is 17 years.
And I would have to conclude that the 17 year number
is likely to be closer to the truth (based on old computers
still in a running state, like my first computer from
1998-1999 or so which still operates just fine).

The Arrhenius effect is for real, and operating even
the best electrolytics at high temperature, doesn't
end well. At the highest allowed temperatures, some
of these electrolytics (by calculation) should only
last for 2000 hours. That's what the curve fit data
for accelerated life testing shows. When I say a
number like 17 years, it would be in an item with
proper and copious cooling. Note that electrolytics
themselves get warm in service, depending on the
ripple current being forced through them. The plastic
sleeve on the outside, does not enhance cooling for
those situations. The capacitors in VCore (on the primary
or secondary side) could be experiencing high ripple currents.
And if any are to fail, those should go first. The
"bulk" decouplers placed near a PCI or PCIe slot,
those aren't under nearly the same stress level.


There are three types of capacitor we should be considering he

Standard electrolytic.
Aluminium electrolytic.
Solid aluminium.

The last two are not the same.
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Old February 9th 20, 10:06 PM posted to uk.d-i-y
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Default Why doesn't everything use solid aluminium capacitors?

Brian Gaff (Sofa 2) wrote

I suppose cos they can get them el chepo. I also have found toward the
end of the 90s, those little tantalum caps that look like blobs of resin
coloured blue tend to go leaky and damage the rest of the circuit.


Dont see much of that anymore.

Nothing is supposed to last any more.


Stainless steel cutlery does. Just noticed that some of our
irrigation control weirs/gates are now entirely stainless
steel. Bet they werent cheap but they certainly will last.

"Commander Kinsey" wrote in message
news[email protected]
Motherboards used them over a decade ago, so why do I still find leaking
electrolytics in TVs?
https://www.extremetech.com/extreme/...herboard-line?




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Old February 9th 20, 10:10 PM posted to alt.comp.os.windows-10,alt.computer.workshop,uk.d-i-y,alt.home.repair
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Default Why doesn't everything use solid aluminium capacitors?

On 09/02/2020 14:18:54, Commander Kinsey wrote:
On Sun, 09 Feb 2020 13:44:19 -0000, Rod Speed
wrote:

Cost.

Commander Kinsey wrote

Motherboards used them over a decade ago, so why do I still find leaking
electrolytics in TVs?


Cost.

https://www.extremetech.com/extreme/...herboard-line?


I tried to find the cheapest normal and solid capacitors on Ebay, as an
example 270uf, 16V:
Normal: https://www.ebay.co.uk/itm/123940375447
Solid: https://www.ebay.co.uk/itm/361349708743
3.94 for normal, 3.83 for solid, so pretty much the same price.
Sizing also almost equal: 12x9mm vs 12x8mm (the solid ones are slightly
smaller)


Try a real world electronics online catalogue

https://www.digikey.co.uk/product-de...861-ND/4843671
vs
https://www.digikey.co.uk/product-de...812-ND/5822363

suggests the costs ratio for your example value is 3x or so for 1,000 off.

You're not coming across as being very bright.

--
Never argue with stupid people like peter hucker, they will drag you
down to their own level and then beat you with experience.


  #26   Report Post  
Old February 9th 20, 10:15 PM posted to uk.d-i-y,alt.home.repair,alt.computer.workshop,alt.comp.os.windows-10
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Default Why doesn't everything use solid aluminium capacitors?

Commander Kinsey wrote

What's wrong with crossposting? There are 4 groups where people might
know the answer. Yes, I could post 4 times seperately, but then people
wouldn't see each other's replies.


And those who read more than one group wouldn't
have the post auto marked as read in the other groups.

I've checked both Ebay and Alibaba (where you can buy huge bulk
quantities), and the prices are no different.


I've never seen the tantalum ones break.


He didn't say break, he said go leaky.

Ii did happen a bit.


On Sun, 09 Feb 2020 16:06:41 -0000, Brian Gaff (Sofa 2)
wrote:


Stop excessive crosposting...

I suppose cos they can get them el chepo. I also have found toward the
end
of the 90s, those little tantalum caps that look like blobs of resin
coloured blue tend to go leaky and damage the rest of the circuit.
Nothing is supposed to last any more.
Brian


  #27   Report Post  
Old February 9th 20, 10:15 PM posted to uk.d-i-y,alt.home.repair,alt.comp.os.windows-10
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Posts: 4,703
Default Troll-feeding Senile ASSHOLE Alert! LOL

On Sun, 09 Feb 2020 15:59:20 -0500, Paul, another miserable, troll-feeding,
senile idiot, blathered:


HTH,
Paul


It WILL help him to jerk off again, you troll-feeding senile asshole!
  #28   Report Post  
Old February 9th 20, 10:30 PM posted to alt.comp.os.windows-10,alt.computer.workshop,uk.d-i-y,alt.home.repair
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Default Troll-feeding Senile ASSHOLE Alert! LOL

On Sun, 9 Feb 2020 21:10:44 +0000, Fredxx, the notorious, troll-feeding,
senile cretin, blathered again:


You're not coming across as being very bright.


Says the senile smartass who refuses to see that he's feeding a retarded
troll, just so he can keep smartassing! tsk
  #29   Report Post  
Old February 9th 20, 10:32 PM posted to uk.d-i-y,alt.home.repair,alt.computer.workshop,alt.comp.os.windows-10
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Posts: 4,703
Default Lonely Auto-contradicting Psychotic Senile Ozzie Troll Alert! LOL

On Mon, 10 Feb 2020 08:15:21 +1100, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

FLUSH the two abnormal sociopathic idiots' idiotic blather

--
Typical retarded "conversation" between the Scottish ****** and the senile
Ozzietard:

Birdbrain: "Horse **** doesn't stink."

Senile Rodent: "It does if you roll in it."

Birdbrain: "I've never worked out why, I assumed it was maybe meateaters
that made stinky ****, but then why does vegetarian human **** stink? Is it
just the fact that we're capable of digesting meat?"

Senile Rodent: "Nope, some cow **** stinks too."

Message-ID:
  #30   Report Post  
Old February 9th 20, 10:37 PM posted to uk.d-i-y
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Default Why doesn't everything use solid aluminium capacitors?

On Sun, 09 Feb 2020 21:06:25 -0000, Rod Speed wrote:

Brian Gaff (Sofa 2) wrote

I suppose cos they can get them el chepo. I also have found toward the
end of the 90s, those little tantalum caps that look like blobs of resin
coloured blue tend to go leaky and damage the rest of the circuit.


Don’t see much of that anymore.

Nothing is supposed to last any more.


Stainless steel cutlery does.


Agreed. I have some that's older than me.

Just noticed that some of our
irrigation control weirs/gates are now entirely stainless
steel. Bet they werent cheap but they certainly will last.


Sometimes, just sometimes, people actually think long term.

"Commander Kinsey" wrote in message
news[email protected]
Motherboards used them over a decade ago, so why do I still find leaking
electrolytics in TVs?
https://www.extremetech.com/extreme/...herboard-line?






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