Stupid polarized capacitor tricks

[Jamie]

having read quite a few of his posts, I doubt he could. Like Philthy,
theory is *not* his strong point.

So we have:

Joel, suggesting something that might work

Joerg & John Larkin agreeing it probably will work

Eeyore (such an appropriate nym!) saying it wont.

3 engineers to 1 technician - it'll probably work.




because he doesnt have many (if any) theoretical skills. look at some of
his older posts - he does this sort of thing all the time, then
hurriedly backs away from providing any theoretical arguments.



^^^^^ ^^
as a pedant, it behoves me to point out these should be "unto"

Cheers
Terry

Ok, so you corrected me there , that's fine.

 

[Jamie]

Jamie wrote:




See my answer to Joel.

Graham

No, I refuse to scary around looking for your answer to Joel just to
give you gratification.

You want gratification? you earn it !

 

[Radiosrfun]

He would, if he had any. As others pointed out - he throws his "idiotic"
answers in - then leaves - because he "can't" prove most of the crap he
writes. I plonked him long ago. The only "smart" thing he did - was pick his
name. It matches perfectly.

 

[Eeyore]

No, I refuse to scary around looking for your answer to Joel just to
give you gratification.

You want gratification? you earn it !

When you learn something useful (and correct for once) about electronics, I'll
consider it.

In the meantime the answer can be found in the same damn thread you're reading.

Hint, part of the answer lies with how electrolytic caps are constructed.

Graham

 

[Eeyore]

Feasible perhaps,

Not even feasible as described. The paper separator between the plates prevents
any possibility of a short.


Graham

 

[Jamie]

Jamie wrote:




When you learn something useful (and correct for once) about electronics, I'll
consider it.

In the meantime the answer can be found in the same damn thread you're reading.

Hint, part of the answer lies with how electrolytic caps are constructed.

Graham

Trying to side track me? I don't give a shit about your theories on
electrolyte and basic principles of electrolytic capacitors.

And to through something back at you pecker head! It's CAPACITORS, not
CAPS !remember? Or are you turning a blind eye to something you quoted
your self?

Nothing new from you. Same old arm chair bull shit.

 

[John Larkin]

and temperature sensors

Cheers
Terry

Way back when AC power distribution was new, ca 1920, there was the
problem of how to charge batteries off the AC line. One cheap homebrew
gadget was the electrolytic rectifier, with one aluminum electrode,
one lead electrode, and a water solution, calcium carbonate or borax
or something, in a glass jar. The oxide film on the aluminum would
form at one polarity, insulating the electrode, and be eaten away on
opposite half-cycles. A home-made fruit-jar rectifier was good for an
amp or two.

Which suggests one could make an aluminum-plate nonvolatile ram with
millisecond write times, sub-ms read times, and a fair number of bits
per sheet. Some nonlinear X-Y bit access mechanism would be necessary,
of course. You could certainly do an aluminum-plate rotating hard
drive that used electrolytic storage; optical readout might be nice.

Which reminds me of the electrolytic PCB bare-board tester I might
build some day.

John

 

[Joel Kolstad]

For starters, the 2 foils are separated by a thin piece of paper, so the
foils
can't touch.

Well...

1) According to what I've read ,the standard aluminum electrolytic cap really
is just a spiral-wound piece of aluminum sitting in a bath of "magic goo"
(initially, it says, a water/glycol mix with an ionic compound such as boric
acid so that it conducts... but these days there's all sort of proprietary
formulas and competition is intense -- hence the whole "leaking caps" on PC
motherboards from a handful of years ago after someone stole another company's
formula and didn't get it quite right), and that sometimes the aluminum oxide
dielectric isn't even formed until after the entire capacitor is constructed,
at which point voltage is applied. It does mention *other* types of
capacitors that use a thin separator (paper, poly-materials, etc), though.

2) The antique radio guys who talk about "reforming" capacitors recommend
using a VARIAC to slowly ramp the voltage up on caps that have been sitting
around awhile, the idea being that without the dielectric is place you really
are looking at something close to a short and applying 120/240V directly will
cause catastrophic failure.

3) In my younger years I'd done the cheeseball "trick" of using two
electrolyitcs "back to back" (polarity-wise) to made a crude non-polarized
capacitor, and it did work in the sense that the cap with reverse polarity on
it behaved as a small resistor.

I guess I'll have to try it out -- I suspect John is correct that "write time"
would be measured in seconds, but still, it'd be fun to do just for the sake
of demonstration.

Thanks for everyone's input.

---Joel

 

[Joel Kolstad]

Which suggests one could make an aluminum-plate nonvolatile ram with
millisecond write times, sub-ms read times, and a fair number of bits
per sheet.

Well, core was in the ballpark of 10us, improving to better than 1us by the
time of its demise... heck, I'd be quite pleased to get 10ms speeds for an
electrolytic capacitor storage device.

Which reminds me of the electrolytic PCB bare-board tester I might
build some day.

I have Joerg's spectrum analyzer on my back burner, since he says it'll sell
like hotcakes, and being the typical engineer that's a good enough business
plan for me.

I realize you're on the wrong end of California, but if you have any
suggestions on cool stuff to visit in San Diego let me know -- I'll be there
this weekend.

---Joel

 

[John O'Flaherty]

having read quite a few of his posts, I doubt he could. Like Philthy,
theory is *not* his strong point.

So we have:

Joel, suggesting something that might work

Joerg & John Larkin agreeing it probably will work

Eeyore (such an appropriate nym!) saying it wont.

3 engineers to 1 technician - it'll probably work.




because he doesnt have many (if any) theoretical skills. look at some of
his older posts - he does this sort of thing all the time, then
hurriedly backs away from providing any theoretical arguments.


^^^^^ ^^
as a pedant, it behoves me to point out these should be "unto"

Actually, it works interestingly as it is. Do onto others as they do
onto you. And before, if possible.

 

[[email protected]]

And if you'd filter the idiot out instead of replying to his drivel, the
rest of us would not have to suffer from seeing his drivel, which I only
do when one of you replies to him, having classed him in the "all noise,
no signal" bin some time ago.

|-----||----|
| DO NOT |
| FEED THE |
| TROLLS! |
|-----||----|
||
||
||
/|\\|/||||//|||/\???\\//\\\\/|?\/\\\\/\/\/\||||\

Responding just
encourages them!
\

')

( \
^^`

 

[Eeyore]

Well...

1) According to what I've read ,the standard aluminum electrolytic cap really
is just a spiral-wound piece of aluminum

2 pieces of aluminium. One for the anode, one for the cathode.

sitting in a bath of "magic goo"
(initially, it says, a water/glycol mix with an ionic compound such as boric
acid so that it conducts... but these days there's all sort of proprietary
formulas and competition is intense -- hence the whole "leaking caps" on PC
motherboards from a handful of years ago after someone stole another company's
formula and didn't get it quite right), and that sometimes the aluminum oxide
dielectric isn't even formed until after the entire capacitor is constructed,
at which point voltage is applied. It does mention *other* types of
capacitors that use a thin separator (paper, poly-materials, etc), though.

I suggest you 'blow up' an electrolytic. Many of us have done it either
accidentally or even intentionally. The 'goo' that results will always contains
'fluff'. That's the paper separator.

My understanding is that the oxide layer on the anode is so thin that it's very
fragile and easily damaged. Hence the reason for the separator. Without it, I
believe you'd too easily get internal shorts from breaches of the oxide layer,
simply from the 2 foils making mechanical contact.

Where did you read that a paper separator ISN'T used ?

2) The antique radio guys who talk about "reforming" capacitors recommend
using a VARIAC to slowly ramp the voltage up on caps that have been sitting
around awhile, the idea being that without the dielectric is place you really
are looking at something close to a short and applying 120/240V directly will
cause catastrophic failure.

Not really a SHORT actually. Probably just a very high reforming current that can
cause trouble.

3) In my younger years I'd done the cheeseball "trick" of using two
electrolyitcs "back to back" (polarity-wise) to made a crude non-polarized
capacitor,

This is precisely how real world 'non-polarised' electrolytics are made.

and it did work in the sense that the cap with reverse polarity on
it behaved as a small resistor.

Neither has reverse polarity on it. The electrolytic cap also works as a crude
electrolytic rectifier. The consequence of this is that on an AC signal, BOTH
charge up in the correct polarity.

I guess I'll have to try it out -- I suspect John is correct that "write time"
would be measured in seconds,

Megaseconds.

Graham

 

[John Devereux]

John Larkin wrote:

[...]

and temperature sensors

Strain gauge.

 

[Engineer]

I realize you're on the wrong end of California, but if you have any
suggestions on cool stuff to visit in San Diego let me know -- I'll be there
this weekend.

The happiest place on earth: Tijuana!!

 

[John Fields]

It's a FACT that's not what happens.

There you go.

 

[John Fields]

Design engineer not a technician thanks.



If you can tolerate read/write times in the megasecond range I suppose you could
say it might work.

That doesn't strike me as being practical.

I can imagine the electrolyte would mess things up too.

 

[John Fields]

Nothing of interest.

For starters, the 2 foils are separated by a thin piece of paper, so the foils
can't touch. Therefore, regardless of the state of the dielectric film on the
anode, there will never be a short.

It's as simple as that.

You could perhaps degrade the capacitance by long term application of a reverse
voltage and measure that change but that's about it.

---
Poor stupid donkey, the paper's only in there to carry the
electrolyte, which is conductive. What keeps the plates from
shorting is the oxide layer on the anode.

From:

http://en.wikipedia.org/wiki/Electrolytic_capacitor

"Without the dielectric material the capacitor will short circuit,
and if the short circuit current is excessive, then the electrolyte
will heat up and either leak or cause the capacitor to explode."

 

[Fred Bloggs]

I was reading a circuits book today that spent more time on the
construction and modeling of components than most do. When I came to
the section on regular old polarized electrolytic capacitors it
occurred to me that you just might be able to turn an electrolytic
capacitor into one bit of non-volatile memory by purposely applying
the correct or reverse polarity to form or remove the dielectric
("write"), and then test for this (by checking to see if the cap
behaves more like a cap or a short ) later ("read").

Does anyone know if this is feasible? In my mind it would make
electrolytic caps sort the "dual" to core memory, which of course
leave ferromagnetic materials near one end or the other of their B-H
curves for later recall.

There are too many unknowns, e-caps are not exactly inexpensive or
miniature, reliability lifetime may be questionable, read and write
access will be relatively slow and power consuming.
The idea seems to be similar to phase change memory with the alteration
of a material characteristic.

Prototype devices switch 500 times faster and use less power

Scientists from IBM (Yorktown Heights, NY), Macronix (Hsinchu, Taiwan,
R.O.C.), and Qimonda (San Jose, CA) have announced research results on
phase-change memory (PCM)—which has the potential to be the successor to
flash. The nonvolatile PCM prototype devices switched more than 500
times faster than flash while using less than one-half the power to
write data. The device's cross-section is only 3 x 20 nm, smaller than
flash can be built today.
http://www.electronicproducts.com/ShowPage.asp?FileName=oljh02.feb2007.html

 

[Ancient_Hacker]

it

"Forming" a capacitor, which means turning aluminum to aluminum oxide,
is a rather slow process. Also it's vulnerable to decay with time and
temperature.

Your basic old EPROM does a similar trick, but just by storing charges
in teensy little isolated wells.

 

[John Larkin]

Well, core was in the ballpark of 10us, improving to better than 1us by the
time of its demise... heck, I'd be quite pleased to get 10ms speeds for an
electrolytic capacitor storage device.


I have Joerg's spectrum analyzer on my back burner, since he says it'll sell
like hotcakes, and being the typical engineer that's a good enough business
plan for me.

Seems like a bump on the end of a USB cable is all you need, sort of
like those Ladybug RF power meters, or the new Agilent knockoffs.

I realize you're on the wrong end of California, but if you have any
suggestions on cool stuff to visit in San Diego let me know -- I'll be there
this weekend.

I haven't spent much time in San Diego, but I've heard that the Hotel
del Coronado is worth a look/stay, and that there are some battleships
or carriers or something you can tour.

One of my customers, Cymer, is in San Diego, but when I visit them I
mostly have to work (frownie.) They make something like 70% of the
deep-UV eximer lasers that expose the world's supply of ICs, and we
make the box that fires the MOPA laser chambers.

John