Stupid polarized capacitor tricks

[Eeyore]

I didnt study his analysis in any detail - because I really dont care;

Likewise. I'm way too familiar with the 'right answer' to need to have to examine
something in detail that he's only bringing up as a stupid troll.

I seldom if ever use mains transformers, and never for any power level
above a few watts, making anything but the crudest analyses unnecessary

when operating a cap/bridge from mains, resistance doesnt really enter
into it, but inductance sure does.

Why do you say (winding) resistance doesn't enter into it ? It's very significant with
typical line frequency transfomers !

Barton has a seriously detailed exposition of the humble
rectifier-capacitor filter (one chapter worth), if you do it properly
its surprisingly complex.

In detail, I have absolutely no doubt.

I just find it frustrating that you often answer posts a-la this thread,
and seldom (if ever) provide any detail whatsoever - I dont recall
seeing any detailed analysis from you, on any topic. IMNSHO those who
can, do; those who cant, generalise.

Some ppl love to 'show off' with their calculations. I don't see the point where the
answer's so obvious. I suggested simulation btw. That'll show anyone the answer without
them even needing to understand the maths.

Graham

 

[John Fields]

Precisely.

---
Hmm...

Once you've been shown the trick you can pretend you knew it all
along.
---

Polarity reversal won't cause a SHORT. It'll be some lowish value resistance
determined by the properties of the electrolyte.

---
What do you think a short _is_ , zero ohms???

Figure a good cap looks like, say, 12 megohms if it's got 12V across
it and 1µA of leakage current, and all of a sudden it starts looking
like its ESR because the oxide is being dissolved into the
electrolyte.

12 megohms in parallel with a few ohms looks like a short to me.

 

[John Fields]

I spent several megamillkilonanomicrogigaseconds trying to
figure that out, but then realized that my time was far better
spent going for a beer....

---
A kilo?

The measure of time, at least, has fucked the metric Nazis.

Even at the macro scale.

60 seconds equals one minute.

60 minutes equals one hour.

24 hours equals one day.

365 days (mas o menos) equals one year.

How inconvenient...

 

[Jamie]

---
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."

Hello John,
I did some consulting work for a capacitor manufacturer company
(Semco), I worked with them to design a robotics assembler to make
mica chip capacitors. I did the electronics and Software interface to
the camera's and servos. Any ways, I just wanted to say, while I was
there on many occasions, I saw many capacitors blow up while in the
environmental test chamber under full stress test.

The 150,000+ uf units really do make some exciting noise!

 

[Jamie]

John Larkin wrote:

[...]

I think that high-K ceramic caps may have enough c-v hysteresis to be
able to store data... maybe even multiple bits per cap, like some
Flash memories.

Ceramic caps are certainly nonlinear enough to make parametric power
amplifiers, and high-voltage nonlinear shock lines.

John

and temperature sensors

Strain gauge.

Ha, I remember making one of those when I was a kid using a
leaded pencil on flat material and then, laminated it with wires
connected on the ends to the rest of the circuit.

 

[Jamie]

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

 

[Terry Given]

Terry Given wrote:




Likewise. I'm way too familiar with the 'right answer' to need to have to examine
something in detail that he's only bringing up as a stupid troll.





Why do you say (winding) resistance doesn't enter into it ? It's very significant with
typical line frequency transfomers !

I'll give you a clue: "when operating a cap/bridge from mains"

In detail, I have absolutely no doubt.





Some ppl love to 'show off' with their calculations. I don't see the point where the
answer's so obvious.

a highly nonlinear circuit like a rectifier/cap filter is "obvious" ?!

I suggested simulation btw. That'll show anyone the answer without
them even needing to understand the maths.

LOL! I make a living out of fixing messes created by people with
simulation software and little or no understanding.

Graham

but you consistently waffle, and essentially never back it up with
theory - ascii schematics, maths etc. Hence my (perhaps erroneous)
conclusion that you are lacking in those skills.

Cheers
Terry

 

[YD]

Late at night, by candle light, Eeyore

Polarity reversal won't cause a SHORT. It'll be some lowish value resistance
determined by the properties of the electrolyte.

Graham

<nit>pick, pick, pick</nit>

So what's the difference if instead of the expected cap you see a low
resistance path? To be a short does it have to be exactly zero ohms or
would an ohm or two be enough?

- YD.

 

[Eeyore]

Late at night, by candle light, Eeyore penned this immortal opus:
<nit>pick, pick, pick</nit>

So what's the difference if instead of the expected cap you see a low
resistance path? To be a short does it have to be exactly zero ohms or
would an ohm or two be enough?

Why don't you try measuring it ?

Graham

 

[YD]

Late at night, by candle light, Eeyore

Why don't you try measuring it ?

Graham

OK, I'll do it if you tell us the set-up and expected outcome.

- YD.

 

[ehsjr]

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").

[...]


And with enough reverse polarity ... phssst ... FOOMP ... you've got the
OTP version with integrated audible and smellable feedback

You gotta love it! WORM. But he wanted non-volatile, and that
WORM would also be VOM (Volatile Once Memory)
Ed

 

[Joerg]

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").

[...]


And with enough reverse polarity ... phssst ... FOOMP ... you've got
the OTP version with integrated audible and smellable feedback

You gotta love it! WORM. But he wanted non-volatile, and that
WORM would also be VOM (Volatile Once Memory)
Ed

Some of them even do a wipe-file operation. Only two pins left after the
plume has wafted off, so hackers cannot figure what was in the memory.

 

[Jamie]

I'll give you a clue: "when operating a cap/bridge from mains"



a highly nonlinear circuit like a rectifier/cap filter is "obvious" ?!


LOL! I make a living out of fixing messes created by people with
simulation software and little or no understanding.



but you consistently waffle, and essentially never back it up with
theory - ascii schematics, maths etc. Hence my (perhaps erroneous)
conclusion that you are lacking in those skills.

Cheers
Terry

Hey, did Mr Ham get a simulator for xmas?

Ha, my kid had one of those when he was in the trade schools.

I would rather find a mistake of my own that I made and not pound
my head for hours to find one that the simulator made.

 

[Guy Macon]

I would rather find a mistake of my own that I
made and not pound my head for hours to find
one that the simulator made.

I feel the same way when the circuit consists
of a few transistors or opamps, but when part
of the circuit is a custom order 90 lb 12-pulse
transformer, simulation reduces the chance of
buying a really expensive iron/copper boat anchor.

The real tragedy is someone who never simulates
or never breadboards, not understanding the basic
concept of different tools for different jobs.

 

[Jamie]

Jamie wrote:




I feel the same way when the circuit consists
of a few transistors or opamps, but when part
of the circuit is a custom order 90 lb 12-pulse
transformer, simulation reduces the chance of
buying a really expensive iron/copper boat anchor.

The real tragedy is someone who never simulates
or never breadboards, not understanding the basic
concept of different tools for different jobs.

You must be referring to those "Arm Chair" you know
what!.
I have always bread boarded when things were question able.

 

[Eeyore]

You must be referring to those "Arm Chair" you know
what!.
I have always bread boarded when things were question able.

'Breadboard' can be very misleading, notably due to large stray capacitances and
questionable interconnection resistance.

The best prototype is constructed on a proper pcb. Anything else is likely to
result in misleading behaviour.

Graham

 

[Jamie]

Jamie wrote:




'Breadboard' can be very misleading, notably due to large stray capacitances and
questionable interconnection resistance.

The best prototype is constructed on a proper pcb. Anything else is likely to
result in misleading behaviour.

Graham

I must say, even though I already knew that. You actually posted
something of some use to those learning. And that is with none of the
normal alienating remarks.

You keep that up and you may make it on my some what ok list.

BTW,
I often use pre drilled etched uni-boards for testing small basic
circuits.

 

[Eeyore]

I must say, even though I already knew that. You actually posted
something of some use to those learning. And that is with none of the
normal alienating remarks.

You keep that up and you may make it on my some what ok list.

If you paid more attention, you might see I do that quite often actually.

Graham

 

[Michael A. Terrell]

Joel Kolstad wrote:

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").


[...]


And with enough reverse polarity ... phssst ... FOOMP ... you've got
the OTP version with integrated audible and smellable feedback

You gotta love it! WORM. But he wanted non-volatile, and that
WORM would also be VOM (Volatile Once Memory)
Ed

Some of them even do a wipe-file operation. Only two pins left after the
plume has wafted off, so hackers cannot figure what was in the memory.

The only semiconductors made on a C-4 substrate? ;-)


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[John Larkin]

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.

Of course it can be made to work. Write a '1' by applying a decent
forward voltage to 'form' the AlO2 layer to some working thickness.
Write a '0' by reverse biasing the cap for a while to erode away the
oxide. Readout is by measuring capacitance.

You could probably store two bits per cap. Three would probably be
pushing it. I think most multilevel Flash chips store two. As noted
elsewhere, electrolytic rectifiers form/destroy 160 volt AlO2 layers
nicely at 60 Hz.

It's easy to say "can't be done" and shut off your brain.

John