IS THERE SUCH A THING AS SUPERCONDUCTIVE CAPACITORS PHEW.
Dliyanka
it's plates became superconductive. Would we discover something new. Has any
one tried this before. I can't bring myself to think that I am the first person
to think of it. If any one knows of research along these lines please drop me a
line.
ThankU
Liyanka :-)
Heh Heh
Dirk Bruere
"Dliyanka" <dliy...@aol.com> wrote in message
news:aklpi8$2gd$1...@lfa221051.richmond.edu...
> What would happen if a charged capacitor was cooled to, say, - 200. So
that
> it's plates became superconductive. Would we discover something new. Has
any
I don't know.
> one tried this before. I can't bring myself to think that I am the first
person
> to think of it. If any one knows of research along these lines please drop
me a
> line.
The problem with things like this is that if someone tried it and nothing
out of the ordinary happened it is very unlikely they are going to write it
up as a paper or get it accepted if they did. Can you imagine a paper
entitled: "Capacitor supercooled for no particular reason - nothing
discovered"?
Yet that is exactly how many major discoveries have been made - by people
'fooling around' and saying 'what do you think would happen if...?'.
However, nobody awards grants for that kind of thing.
Dirk
Uncle Al
Classical BCS supercons don't top 25 K, that's -250 C. You can't get
there without liquid cryogens. Around 40 K you can have mechanical
refrigeration. Layered ceramic HTSC cuprates and such don't like
being wound around small radii of curvature. Refrigeration is
expensive. KISS.
The capacitor wouldn't change (don't try this with electrolytics), but
the current pulse and its magnetic field from the discharge could be
transitionally embarassing. Make the thing out of layers of doped
semiconductor and MgB2. At ambient temp the semiconductor is the
electrodes and the MgB2 is the dielectric. At 4 K the semiconductor
is the dielectric and the MgB2 is the electrodes.
Consider a Moebius band capacitor - you only have to worry about
electric field fringing on one edge.
--
Uncle Al
http://www.mazepath.com/uncleal/eotvos.htm
(Do something naughty to physics)
"Quis custodiet ipsos custodes?" The Net!
Joseph.D.Warner
Dliyanka wrote:
>
> What would happen if a charged capacitor was cooled to, say, - 200. So that
> it's plates became superconductive. Would we discover something new.
No
> Has any one tried this before.
Yes
>If any one knows of research along these lines please drop me a
> line.
Capacitors are made all the time for superconductors. When ever a planar
resonator is made. Look up HTS and microwaves. Also, capacitors are made
for J-Js. Some of them are Superconductor/Insulator/Superconductor
geometry. It just that the insulator is so thin you get tunnelling. But
people people first look at thicker insulators and just do basic
capacitance measurements to find out the quality of the insulator, ie.
dielectric constant (real and imaginary), and pinholes and such. Nothing
extra-ordinary happens. The capacitor just behaves, for thick
insulators, as a capacitor with the metal having either zero resistance
(DC case), or extremely low surface resistance (low frequency AC).
The quality factor of a circuit made from HTS- capacitors and inductors
usually much higher than for conventional circuits.
leoleo
wrote:
A similar but unrelated question:
What is the capacity of a metal?
It is correct to say that its dielectric constant is infinite?
What does it physically means?
Doug Goncz
milliohms, I believe. A more involved measurement is imedance spectroscopy,
merely a data set or graph show the relationship between frequency from zero
(DC) to some arbitrary limit, and E.S.R.
Electrolytics freeze at low temperatures. There are a few other types of
capacitors. A double layer cap might have ESR ratings in the low ohms or less.
They have a low power density, and high energy density. Electrolytics are the
opposite. Ceramics are low in both characteristics. Then there's oil, paper,
and tantalum.
So far from the superconducting regime, we have a multi plot showing the
results of impedance spectroscopy at various temperatures. Now that's likely to
have been published many years ago, and now is internal to capacitor
manufacturers. So you either find a library with very old journals, or write a
maker looking for app notes.
Another angle is to look for measurements of both dielectric constant and
refractive index at DC, various frequencies, and in the visible range, as
functions of temperature. Look for a pole and see what happens at that
frequency as you go to cryogenic temps.
A more practical way to see what happens to capacitance as temperature changes
is to charge two more-or-less identical caps in parallel to the same voltage.
Put one in the freezer. Keep it dry. Take it out later, and put a bidirectional
milliameter in between it and the other. Short the other two terminals. Likely
the meter will deflect.
Can you predict the deflection direction on careful inspection of the
protection selection?
Could there be some energy synergy? Perhaps some dielectric divergence.
Oh, God, I've had too many donuts. I'd better stop here before I emb.....
Yours,
Doug Goncz, Replikon Research, Seven Corners, VA (remove pee dot mil antispam)
http://users.aol.com/DGoncz
http://groups.google.com/groups?as_q=DGoncz
"Function, Funding, Form, Fit, and Finish"