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bipolar aluminum caps

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  bipolar aluminum caps John Larkin <jjlarkin@highlandtechnology.com> - 2016-10-13 07:01 -0700
    Re: bipolar aluminum caps George Herold <gherold@teachspin.com> - 2016-10-13 07:11 -0700
      Re: bipolar aluminum caps Robert Baer <robertbaer@localnet.com> - 2016-10-15 00:38 -0800
    Re: bipolar aluminum caps tabbypurr@gmail.com - 2016-10-13 07:34 -0700
      Re: bipolar aluminum caps Reinhardt Behm <rbehm@hushmail.com> - 2016-10-13 22:58 +0800
      Re: bipolar aluminum caps John Larkin <jjlarkin@highlandtechnology.com> - 2016-10-13 08:44 -0700
        Re: bipolar aluminum caps tabbypurr@gmail.com - 2016-10-13 08:59 -0700
          Re: bipolar aluminum caps George Herold <gherold@teachspin.com> - 2016-10-13 09:14 -0700
            Re: bipolar aluminum caps "Tim Williams" <tiwill@seventransistorlabs.com> - 2016-10-14 03:40 -0500
              Re: bipolar aluminum caps Syd Rumpo <usenet@nononono.co.uk> - 2016-10-14 09:52 +0100
                Re: bipolar aluminum caps "Tim Williams" <tiwill@seventransistorlabs.com> - 2016-10-14 03:59 -0500
                  Re: bipolar aluminum caps Syd Rumpo <usenet@nononono.co.uk> - 2016-10-14 11:01 +0100
                    Re: bipolar aluminum caps "Tim Williams" <tiwill@seventransistorlabs.com> - 2016-10-14 21:48 -0500
                Re: bipolar aluminum caps tabbypurr@gmail.com - 2016-10-14 02:18 -0700
        Re: bipolar aluminum caps Robert Baer <robertbaer@localnet.com> - 2016-10-15 00:45 -0800
          Re: bipolar aluminum caps krw <krw@nowhere.com> - 2016-10-15 11:06 -0400
            Re: bipolar aluminum caps tabbypurr@gmail.com - 2016-10-15 08:23 -0700
              Re: bipolar aluminum caps krw <krw@nowhere.com> - 2016-10-15 19:39 -0400
          Re: bipolar aluminum caps Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> - 2016-10-18 21:23 -0400
      Re: bipolar aluminum caps Robert Baer <robertbaer@localnet.com> - 2016-10-15 00:42 -0800
        Re: bipolar aluminum caps krw <krw@nowhere.com> - 2016-10-15 11:07 -0400
          Re: bipolar aluminum caps Robert Baer <robertbaer@localnet.com> - 2016-10-17 09:28 -0800
            Re: bipolar aluminum caps krw <krw@nowhere.com> - 2016-10-17 19:52 -0400
              Re: bipolar aluminum caps John Larkin <jjlarkin@highlandtechnology.com> - 2016-10-17 17:29 -0700
              Re: bipolar aluminum caps Robert Baer <robertbaer@localnet.com> - 2016-10-19 13:06 -0800
    Re: bipolar aluminum caps Joerg <news@analogconsultants.com> - 2016-10-13 09:14 -0700
    Re: bipolar aluminum caps Frank Miles <fpm@u.washington.edu> - 2016-10-13 17:15 +0000
      Re: bipolar aluminum caps John Larkin <jjlarkin@highlandtechnology.com> - 2016-10-13 11:42 -0700
        Re: bipolar aluminum caps Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2016-10-13 14:52 -0400
          Re: bipolar aluminum caps John Larkin <jjlarkin@highlandtechnology.com> - 2016-10-13 11:56 -0700
          Re: bipolar aluminum caps "David Eather" <eather@tpg.com.au> - 2016-10-15 14:53 +1000
      Re: bipolar aluminum caps "David Eather" <eather@tpg.com.au> - 2016-10-15 14:52 +1000
    Re: bipolar aluminum caps Tim Wescott <tim@seemywebsite.really> - 2016-10-13 19:41 -0500
      Re: bipolar aluminum caps "Tim Williams" <tiwill@seventransistorlabs.com> - 2016-10-14 03:43 -0500
        Re: bipolar aluminum caps Tim Wescott <seemywebsite@myfooter.really> - 2016-10-14 12:19 -0500
          Re: bipolar aluminum caps "Tim Williams" <tiwill@seventransistorlabs.com> - 2016-10-14 22:18 -0500
    Re: bipolar aluminum caps krw <krw@nowhere.com> - 2016-10-13 20:57 -0400
      Re: bipolar aluminum caps John Larkin <jjlarkin@highlandtechnology.com> - 2016-10-13 18:05 -0700
        Re: bipolar aluminum caps krw <krw@nowhere.com> - 2016-10-13 21:39 -0400
          Re: bipolar aluminum caps "Tim Williams" <tiwill@seventransistorlabs.com> - 2016-10-14 03:44 -0500
            Re: bipolar aluminum caps whit3rd <whit3rd@gmail.com> - 2016-10-14 12:22 -0700
    Re: bipolar aluminum caps whit3rd <whit3rd@gmail.com> - 2016-10-13 18:01 -0700
    Re: bipolar aluminum caps alpibucky <alpibucky@mail.be> - 2016-10-14 22:23 +0200
    Re: bipolar aluminum caps Robert Baer <robertbaer@localnet.com> - 2016-10-15 00:35 -0800
      Re: bipolar aluminum caps Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> - 2016-10-18 21:22 -0400

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#431099 — bipolar aluminum caps

High-K ceramic caps are awful. They lose 90% of their capacitance at
rated voltage.

Are bipolar aluminum caps reliable?

I would think that polymer aluminum caps would make good nonpolarized
things, but there don't seem to be any.


-- 

John Larkin         Highland Technology, Inc

lunatic fringe electronics 

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#431100

On Thursday, October 13, 2016 at 10:02:02 AM UTC-4, John Larkin wrote:
> High-K ceramic caps are awful. They lose 90% of their capacitance at
> rated voltage.
> 
> Are bipolar aluminum caps reliable?

Never used them... I made my own years ago by sticking two Al electro's 
in series.  I'm guessing they would stink at high frequency.  
George H.   
> 
> I would think that polymer aluminum caps would make good nonpolarized
> things, but there don't seem to be any.
> 
> 
> -- 
> 
> John Larkin         Highland Technology, Inc
> 
> lunatic fringe electronics

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#431273

George Herold wrote:
> On Thursday, October 13, 2016 at 10:02:02 AM UTC-4, John Larkin wrote:
>> High-K ceramic caps are awful. They lose 90% of their capacitance at
>> rated voltage.
>>
>> Are bipolar aluminum caps reliable?
>
> Never used them... I made my own years ago by sticking two Al electro's
> in series.  I'm guessing they would stink at high frequency.
* No more than singles.
   A smaller mylar in parallel can do wonders.

> George H.
>>
>> I would think that polymer aluminum caps would make good nonpolarized
>> things, but there don't seem to be any.
>>
>>
>> --
>>
>> John Larkin         Highland Technology, Inc
>>
>> lunatic fringe electronics
>

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#431101

On Thursday, 13 October 2016 15:02:02 UTC+1, John Larkin  wrote:
> High-K ceramic caps are awful. They lose 90% of their capacitance at
> rated voltage.
> 
> Are bipolar aluminum caps reliable?
> 
> I would think that polymer aluminum caps would make good nonpolarized
> things, but there don't seem to be any.

Tants make good bipolars ;)


NT

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#431105

AT Thursday 13 October 2016 22:34, tabbypurr@gmail.com wrote:

> On Thursday, 13 October 2016 15:02:02 UTC+1, John Larkin  wrote:
>> High-K ceramic caps are awful. They lose 90% of their capacitance at
>> rated voltage.
>> 
>> Are bipolar aluminum caps reliable?
>> 
>> I would think that polymer aluminum caps would make good nonpolarized
>> things, but there don't seem to be any.
> 
> Tants make good bipolars ;)

But then they tend to lose the magic smoke.

-- 
Reinhardt

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#431114

On Thu, 13 Oct 2016 07:34:23 -0700 (PDT), tabbypurr@gmail.com wrote:

>On Thursday, 13 October 2016 15:02:02 UTC+1, John Larkin  wrote:
>> High-K ceramic caps are awful. They lose 90% of their capacitance at
>> rated voltage.
>> 
>> Are bipolar aluminum caps reliable?
>> 
>> I would think that polymer aluminum caps would make good nonpolarized
>> things, but there don't seem to be any.
>
>Tants make good bipolars ;)
>
>
>NT

For a while. There's engineering lore that dry tants are OK at -10% of
rated voltage, or something.


-- 

John Larkin         Highland Technology, Inc

lunatic fringe electronics 

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#431117

On Thursday, 13 October 2016 16:44:35 UTC+1, John Larkin  wrote:
> On Thu, 13 Oct 2016 07:34:23 -0700 (PDT), tabbypurr wrote:
> >On Thursday, 13 October 2016 15:02:02 UTC+1, John Larkin  wrote:
> >> High-K ceramic caps are awful. They lose 90% of their capacitance at
> >> rated voltage.
> >> 
> >> Are bipolar aluminum caps reliable?
> >> 
> >> I would think that polymer aluminum caps would make good nonpolarized
> >> things, but there don't seem to be any.
> >
> >Tants make good bipolars ;)
> 
> For a while. There's engineering lore that dry tants are OK at -10% of
> rated voltage, or something.

I didn't know that. Long ago I stuffed a regular lytic wrong and it worked fine... at -23v on a 16v cap. I don't think I'd use that in production though :)


NT

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#431121

On Thursday, October 13, 2016 at 12:00:04 PM UTC-4, tabb...@gmail.com wrote:
> On Thursday, 13 October 2016 16:44:35 UTC+1, John Larkin  wrote:
> > On Thu, 13 Oct 2016 07:34:23 -0700 (PDT), tabbypurr wrote:
> > >On Thursday, 13 October 2016 15:02:02 UTC+1, John Larkin  wrote:
> > >> High-K ceramic caps are awful. They lose 90% of their capacitance at
> > >> rated voltage.
> > >> 
> > >> Are bipolar aluminum caps reliable?
> > >> 
> > >> I would think that polymer aluminum caps would make good nonpolarized
> > >> things, but there don't seem to be any.
> > >
> > >Tants make good bipolars ;)
> > 
> > For a while. There's engineering lore that dry tants are OK at -10% of
> > rated voltage, or something.
> 
> I didn't know that. Long ago I stuffed a regular lytic wrong and it worked fine... at -23v on a 16v cap. I don't think I'd use that in production though :)
> 
> 
> NT

I don't know dry from wet tant's, but I had a 35 V (4.7uF) through hole tant last 
for years (intermittent use) when put in backwards in 5V regulator.  

George H. 

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#431186

"George Herold" <gherold@teachspin.com> wrote in message 
news:a790b67d-fce2-42e4-85cf-15d2b6dd1c76@googlegroups.com...
> I don't know dry from wet tant's, but I had a 35 V (4.7uF) through hole 
> tant last
> for years (intermittent use) when put in backwards in 5V regulator.

If you have to ask its price, and you get an answer: it's a dry tant.

Dry tants are usually rated for "5% or 3V, whichever is higher [in 
magnitude]", reverse.  More than that is definitely your own gamble.

Don't know about wet, but I can't say I like the idea of boiling sulfuric 
acid gel splattered in my face!

Aluminum electrolytics tend to put up with quite a lot of abuse (including 
bipolar operation*, gasp!), as long as it's done slowly (so the oxide layer 
can reform).

*Proper bipolar caps are different, yes.  They're about double the size of a 
regular kind (for obvious reasons?).  But a regular cap will last, with a 
modest reversal, given a similar provisio to the above.

Electrolytics,m over limit, tend to fail with a time constant of ~months. 
YMMV.

Tim

-- 
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
Website: http://seventransistorlabs.com 

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#431189

On 14/10/2016 09:40, Tim Williams wrote:

<snip>

> Aluminum electrolytics tend to put up with quite a lot of abuse
> (including bipolar operation*, gasp!), as long as it's done slowly (so
> the oxide layer can reform).

That's interesting. Does it imply that Al electrolytics can withstand 
short bursts of reverse voltage, as long as the average is substantially 
the correct polarity?

If so, I wonder how long they'd withstand a reverse - seconds, minutes - 
I suppose it would be stated as volt seconds per farad?

Cheers
-- 
Syd

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#431192

"Syd Rumpo" <usenet@nononono.co.uk> wrote in message 
news:ntq6bq$9rf$1@dont-email.me...
> If so, I wonder how long they'd withstand a reverse - seconds, minutes - I 
> suppose it would be stated as volt seconds per farad?

Sure!  You might want to put a fuse in series with it though. ;-)

(The intended joke is non-obvious.  Do the unit analysis! :) )

Tim

-- 
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
Website: http://seventransistorlabs.com 

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#431198

On 14/10/2016 09:59, Tim Williams wrote:
> "Syd Rumpo" <usenet@nononono.co.uk> wrote in message
> news:ntq6bq$9rf$1@dont-email.me...
>> If so, I wonder how long they'd withstand a reverse - seconds, minutes
>> - I suppose it would be stated as volt seconds per farad?
>
> Sure!  You might want to put a fuse in series with it though. ;-)
>
> (The intended joke is non-obvious.  Do the unit analysis! :) )
>
> Tim
>
Yes, the capacitance won't come into it if I'm considering a voltage. 
Volt seconds alone is too simplistic.

What units would be appropriate?

Cheers
-- 
Syd

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#431261

"Syd Rumpo" <usenet@nononono.co.uk> wrote in message 
news:ntqadj$mrc$1@dont-email.me...
> What units would be appropriate?

Hmm, probably just charge.  Should be independent of voltage rating, but 
proportional to capacitance, so, you'd have a ratio of charge to 
capacitance....... which is a voltage, but not the rated voltage. :o)

The amount of "voltage" necessary to reform the cap, may depend on the rated 
voltage as well (higher rating = thicker oxide to form / reform / deform). 
In which case, dividing by that gives a dimensionless "electrolytic reform" 
voltage gain!

Tim

-- 
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
Website: http://seventransistorlabs.com 

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#431194

On Friday, 14 October 2016 09:52:32 UTC+1, Syd Rumpo  wrote:
> On 14/10/2016 09:40, Tim Williams wrote:
> 
> <snip>
> 
> > Aluminum electrolytics tend to put up with quite a lot of abuse
> > (including bipolar operation*, gasp!), as long as it's done slowly (so
> > the oxide layer can reform).
> 
> That's interesting. Does it imply that Al electrolytics can withstand 
> short bursts of reverse voltage, as long as the average is substantially 
> the correct polarity?
> 
> If so, I wonder how long they'd withstand a reverse - seconds, minutes - 
> I suppose it would be stated as volt seconds per farad?

keeping time down isn't the issue. Keeping i down while the oxide forms is.
I've not tested it, but guess C reduces when they're reverse formed.


NT

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#431275

John Larkin wrote:
> On Thu, 13 Oct 2016 07:34:23 -0700 (PDT), tabbypurr@gmail.com wrote:
>
>> On Thursday, 13 October 2016 15:02:02 UTC+1, John Larkin  wrote:
>>> High-K ceramic caps are awful. They lose 90% of their capacitance at
>>> rated voltage.
>>>
>>> Are bipolar aluminum caps reliable?
>>>
>>> I would think that polymer aluminum caps would make good nonpolarized
>>> things, but there don't seem to be any.
>>
>> Tants make good bipolars ;)
>>
>>
>> NT
>
> For a while. There's engineering lore that dry tants are OK at -10% of
> rated voltage, or something.
>
>
   Yes; that is the "standard trick" of order-of-magnitude derating.
   But even so, still having the possibility of fireworks.

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#431300

On Sat, 15 Oct 2016 00:45:01 -0800, Robert Baer
<robertbaer@localnet.com> wrote:

>John Larkin wrote:
>> On Thu, 13 Oct 2016 07:34:23 -0700 (PDT), tabbypurr@gmail.com wrote:
>>
>>> On Thursday, 13 October 2016 15:02:02 UTC+1, John Larkin  wrote:
>>>> High-K ceramic caps are awful. They lose 90% of their capacitance at
>>>> rated voltage.
>>>>
>>>> Are bipolar aluminum caps reliable?
>>>>
>>>> I would think that polymer aluminum caps would make good nonpolarized
>>>> things, but there don't seem to be any.
>>>
>>> Tants make good bipolars ;)
>>>
>>>
>>> NT
>>
>> For a while. There's engineering lore that dry tants are OK at -10% of
>> rated voltage, or something.
>>
>>
>   Yes; that is the "standard trick" of order-of-magnitude derating.
>   But even so, still having the possibility of fireworks.

When I was in IBM, we used tantalums by the millions (perhaps a
thousand per system).  The only problems we ran into were reverse
insertion but that could be spectacular and occur years later.  Our
design ground rules called for a voltage de-rating of 2-3 times (no
more), not much different that ceramics (though for different
reasons;-).  We didn't use aluminums.  These were 100K hour
applications.  

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#431302

On Saturday, 15 October 2016 16:08:26 UTC+1, krw  wrote:
> On Sat, 15 Oct 2016 00:45:01 -0800, Robert Baer
> <robertbaer> wrote:
> >John Larkin wrote:
> >> On Thu, 13 Oct 2016 07:34:23 -0700 (PDT), tabbypurr wrote:

> >>> Tants make good bipolars ;)
> >>
> >> For a while. There's engineering lore that dry tants are OK at -10% of
> >> rated voltage, or something.
> >>
> >   Yes; that is the "standard trick" of order-of-magnitude derating.
> >   But even so, still having the possibility of fireworks.
> 
> When I was in IBM, we used tantalums by the millions (perhaps a
> thousand per system).  The only problems we ran into were reverse
> insertion but that could be spectacular and occur years later.  Our
> design ground rules called for a voltage de-rating of 2-3 times (no
> more), not much different that ceramics (though for different
> reasons;-).  We didn't use aluminums.  These were 100K hour
> applications.

if you can control peak current they're fine. The problem is many have thought current was under control and found later due to tant failures that it wasn't.


NT

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#431352

On Sat, 15 Oct 2016 08:23:15 -0700 (PDT), tabbypurr@gmail.com wrote:

>On Saturday, 15 October 2016 16:08:26 UTC+1, krw  wrote:
>> On Sat, 15 Oct 2016 00:45:01 -0800, Robert Baer
>> <robertbaer> wrote:
>> >John Larkin wrote:
>> >> On Thu, 13 Oct 2016 07:34:23 -0700 (PDT), tabbypurr wrote:
>
>> >>> Tants make good bipolars ;)
>> >>
>> >> For a while. There's engineering lore that dry tants are OK at -10% of
>> >> rated voltage, or something.
>> >>
>> >   Yes; that is the "standard trick" of order-of-magnitude derating.
>> >   But even so, still having the possibility of fireworks.
>> 
>> When I was in IBM, we used tantalums by the millions (perhaps a
>> thousand per system).  The only problems we ran into were reverse
>> insertion but that could be spectacular and occur years later.  Our
>> design ground rules called for a voltage de-rating of 2-3 times (no
>> more), not much different that ceramics (though for different
>> reasons;-).  We didn't use aluminums.  These were 100K hour
>> applications.
>
>if you can control peak current they're fine. The problem is many have thought current was under control and found later due to tant failures that it wasn't.

Used as bypasses for 1KA supplies, there wasn't much current control.
They were fine, as long as they were inserted and de-rated properly.

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#431750

On Sat, 15 Oct 2016 00:45:01 -0800, the renowned Robert Baer
<robertbaer@localnet.com> wrote:

>
>>
>   Yes; that is the "standard trick" of order-of-magnitude derating.
>   But even so, still having the possibility of fireworks.

You can just put a resistor in series. At least a few ohms. The more
the better (and the worse the filtering). 

--sp 

-- 
Best regards, 
Spehro Pefhany
Amazon link for AoE 3rd Edition:            http://tinyurl.com/ntrpwu8

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#431274

tabbypurr@gmail.com wrote:
> On Thursday, 13 October 2016 15:02:02 UTC+1, John Larkin  wrote:
>> High-K ceramic caps are awful. They lose 90% of their capacitance at
>> rated voltage.
>>
>> Are bipolar aluminum caps reliable?
>>
>> I would think that polymer aluminum caps would make good nonpolarized
>> things, but there don't seem to be any.
>
> Tants make good bipolars ;)
>
>
> NT
   A monopolar tantalum is shit at inverse voltage, and you take the 
risk of explosion. Even if you do the standard of derating by an order 
of magnitude.

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