I have a question (mainly of academic interest) about capacitors.
I read in my physics text book that polar substances such as water have a much higher dielectric constant (K) than vacuum because the polar molecules align so as to negate the voltage across the plates.
So, could you get the same effect with a dielectric comprising small bits of conductor (e.g. iron filings or graphite powder) embedded in an insulator (oil, clay, whatever)?
It seems to me that the small pieces of conductor would polarize similarly to the molecular polarization of water, but maybe better.
Water in its *PURE* state is a nearly perfect insulator. SO the IDEA is good. In practice, though...
Water with even a little contamination is anywhere from a medium-poor conductor to better than a copper wire as a conductor, depending on the type and quantity of contaminant.
Water-dielectric capacitors have been tried - and found wanting - by the tesla coil types. They work great - ONCE. Generally, by the time the second shot is ready to happen, the water has already been contaminated enough by the metal plates leaching into it that it's worthless (or at least lousy) as a capacitor, and the coil doesn't fire worth diddly.
On the other hand, there is the so-called "6-pack" capacitor - 6 long-neck bottles from your favorite brand of beer that comes in straight-sided bottles. Wrap each one in tinfoil, as smooth and wrinkle-free as humanly possible. Set them all on another sheet of tinfoil, so that all of them are electrically connected. Now fill them all with a saturated NaCl solution (AKA "Brine"), topped with an inch or two of U.S.P Mineral Oil, then corked (usually with rubber stoppers). Connect wires to 6 large nails, and drive the nails through the rubber stoppers/corks, through the oil, and into contact with the brine. Run the 6 wires together to a terminal. The other terminal is the sheet of tinfoil the bottles are sitting on. Presto - One fairly large value capacitor suitable for the high-voltage work involved with running a Tesla coil - The tinfoil on the outside is one plate, the brine on the inside is the other plate, the glass of the bottle is the dielectric.
--
Don Bruder - dakidd@sonic.net - If your "From:" address isn\'t on my whitelist,
or the subject of the message doesn\'t contain the exact text "PopperAndShadow"
somewhere, any message sent to this address will go in the garbage without my
ever knowing it arrived. Sorry... for more info
Sounds doubtful. Energy is stored in the molecule/atoms of the dielectric - they deform physically under an electrostatic field. - the reason why some dielectrics are good at some frequencies and lossy at others (dissipation factor changes with frequency) A conductor introduced into the dielectric material might work - but because it may serve to bring the plates closer together- effectively speaking - and decrease the insulating ability of the dielectric - so it might have to be thicker. zero gain
----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
formatting link
The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----
I'd wondered about just using an insulated metal plate as the dialectric. But I analyzed it as two capacitors in series, and didn't get the result I'd hoped for.
Pure water is also I think diamagnetic. What about deionized water?
Like a ferrite core? Ferrite is too hard to make.
An auto repair shop with a brake drum/disk grinder is a good place to pick up some free iron filings. They could be embedded in epoxy or fiberglass resion but it would not be anywhere the same as ferrite.
What kind of voltages are you thinking about? Some dilectrics work well only for certain voltage ranges.
What about trying some 'metal' cassette tape?
It's hard to control the property of liquid suspensions when temperature is always moving things around. Try suspending iron filings in gelatine or ...
Faraday wasn't recognized much for his academics. If you want an exciting read, try his Experimental Researches in Electricity. It gave me a great respect and inspiration for actual experimentation. Then read Maxwell. There's an order to the universe.
I think your physics book has over simplified it. I don't belive that it is a simple matter of "negating the voltage across the plates" but a case of the distorion created in polar molecules by the electric field. That distortion is a form of energy storage and has the effect of increasing the capacitance which shows as high dielectric constant. Negating the voltage implies some sort of conductor within the dialectric which is what you are asking. But that's not the phenomenon so I doubt it would be successful. Bob
Do you have ANY idea how difficult it will be for me to build this once I empty those 6 bottles of Tyranena Porter? I probably shouldn't be playing with tesla coils, either.
Glass plate caps with aluminum flashing for plates and 3/32" picture frame glass work just fine - pot in wood boxes with paraffin - a single homemade (layered - low ESR) cap across lots of commercial units will make a Tesla coil get hopping.
Really? drinking beer to make caps? Well, I can't be too critical. I drank two cases of "Carling Black Label" (only beer we had in all steel cans - $2.60 - 24 can cases) to build an antenna. In my Navy days.
----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
formatting link
The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----
I don't have a basement, and live in a warm climate. I brew in October, through June. I do 18 cases a year plus whatever I consume while brewing.
Where do you live? Dig a "root cellar?" I've been toying with that idea - hurricane protection, and a great wine cellar - and what better way to wait out a hurricane (unless the water starts creeping up in the cellar) Life is rough - don't fight it.
----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
formatting link
The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----
Water (very pure de ionized) would seem to be a good dielectric. but DI water has this habit of finding ions from anything (even plastic) so you'd probably end up circulating the water and introducing fresh DI.
I know a lab where they used DI water and the CATION, and ANION resin (beds) tanks were close to the spigots - for months they tried to convince me they were in dire danger from electrocution because of the wiring. I could never measure anything with my meters. I remembered this old Scientific American article on building a static electricity generator from just a big tank spraying water . . . added a grounded brass nozzle to their plastic spigot and they were happy.
----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
formatting link
The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----
Apply an electrostatic field and the molecules and electron orbits distort. That distortion stores more energy than a vacuum would. Discharge the cap, and the stored energy (all those bent up electrons) is given up in the form or electron flow. How fast a particular compound will release the energy is a matter of dissipation factor.
OR, from an AC perspective:
In addition to pure electron attraction manipulating the dielectric compounds - there are mechanical considerations as well - resonance of the molecules in the dielectric. Just like MRI machines - excite a dielectric and it responds at its own pace. A dielectric that will be efficient at 10 MHZ might not at 20 MHz - Most dielectrics that are efficient (less dissipated heat) at low frequencies will be good at high frequencies - BUT NOT ALL - so you look at the specs for the frequency you are using, or check a chart that covers your freq. or check the manufacturer's specs. Same thing with microwave ovens.
Maynard Fergusen died. Damn
----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
formatting link
The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.