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Build Your Own Tesla Coil
screenbert writes "Ever wanted to keep stray dogs or neighbors from trampling your backyard, but
just couldn't find the system to really deter them? Well this
site shows how they built
a bi-polar Tesla Coil system. I've always loved the Tesla coils on C&C when
they'd zap the units as they went by.
"
The Tesla Coil in truth wasn't really about electricity being used against humans a la bug-zapper. The Tesla Coil was actually a ginat coil that Tesla devised that could shake an entire building apart. The Tesla coil was actually a harmonics device. But, I like the idea of the zapper better... ;)
My $0.02.
My father found an old Popular Electronics (or something) magazine from his hobby days with some plans. We hand wound the voltage stepup coil, made condensors out of perspex plates and tinfoil, and borrowed a Ruhmkorff Induction Coil from school.
The unit was powered by a car battery and could spark about an inch and a half.
We put two bent copper rods for the spark to jump between. The spark would run up and down between these rods like old mad-scientist movies.
It felt pretty cool to put a finger in the spark and watch it jump straight through, with only a weird tingling sensation.
Aaah the electric shocks, the smell of ozone, the burns and blisters - God I miss science fairs.
Did anyone else notice that if you click on one of the three pictures at the bottom of the pages, it brings up a new page with that image? Try clicking on segments of that image... Interesting way to have an online photo-album. Seriously, has anyone else determined what relevence the colors have to the pictures, and where you click versus what type of image you get?
.noitacidem deen uoy siht daer nac uoy fI
it's a site map. Ingenious!p .html
http://www.edm.net/~jwilliams/Site_Ma
.noitacidem deen uoy siht daer nac uoy fI
and theres a damn good reason its 100ma,
... assuming you DONT want to kill stuff :)
(from Electrical Saftey Engineering 2nd Edition)
Physioligcial Reaction to Current
3-5 mA Barely Perceptible
35-50 mA Extreme Pain
50-70 mA Muscle Paralysis
500mA Heart Stoppage (books word not mine)
Besides, dialectric strength is like voltage*thickness right? So a high current would be a waste of electricity
Religion is a gateway psychosis. -- Dave Foley
I would be polite to point out that you are building a voltage divider. with zero volts at ground. 10,000 volts at the terminal. There are two resisters, the person (R_p) and the air (R_a). So the current I=10,000/(R_p+R_a). If we model R_a as linear with distance, then for some proportionality constant (c), R_a=c*x.
So then, I=10,000/(R_p+c*x).
I->10,000/(c*x) for large x,
and I-> 10,000/R_p for small x.
This is neither an exponential drop off nor a constant current.
I would like a further description of the mobius strip, and an explanation of wtf a electrotemporaltopological disaster is,,, I'm sorry for my ignorance in this area, but I have a need to know.... After all I might want to make one of these .. J/K... But if this is so dangerous and easy to build why hasn't some country produced one and vaporized (or electrotemporaltopologicaly destroyed) some city?
I've wanted to build a Tesla coil for years.
:).
The reason I still haven't is that they're about as good for electronics and magnetically sensitive media as a lightning strike. The intermittent arc gives off *vast* amounts of RF crud, which will induce currents in just about anything electronic and degauss anything magnetic nearby.
Your computer case will not save you if your machine has drive bays. All connected wires (modem, network, power) will also act perfectly well as antennas penetrating the case's shielding.
Credit cards and bank cards generally aren't shielded at all
Set up those Faraday cages before building anything like this.
Finnaly someone showed this to the public. It really is an old idea, but in the world we live now, it has some interesting effects. I was tracing the development of such toys based on Nikola Tesla's ideas for a while now and found a lot of impresive stuff. Just do a quick search on "telsa weapon" and read some of the articles that pop up. One of the most scary is located at http://www.peg.apc.org/~nexus/bskies1[2345].html (yeah thats five parts of it). Hints about causing earthquakes with similiar technology as described in the story above. Other interesting sites are Gravity gate http://www.starwon.com.au/~rayd/index.htm, Kelly BBS www.kellynet.com, Tesla web ring and similiar. If you like to search a lot, you may even find hints about top secret super high tech weapons developed in Russia for knocking out satelites, which are also based on one of the Tesla's ideas and are powered by also originaly Tesla's work, improved by dr. H. Moray, the so called Moray generator. Basicaly you just set up an antenna and some electronic wizardry and you have electricity. Sounds too good to be true, but there's a story on the kellynet about how Tesla made an electric car powered by such a device.
:) And the next thing would be to cover my house entirely in somekind of conductive mesh, to make more or less effective faradey cage. I feel like protecting computers and other electronic equipment will be big bussiness in the next decades.
Back to the EMP stuff...does anyone have some nice information about project HAARP and similiar "experiments" all around the world? I heard somewhere that US military already developed their small EMP "bomb" for knocking out "e-criminals". I would like to take a look at one of those toys
Does it go on forever?
You can easily make a Tesla coil if you have an old busted TV to rip apart. In general, the older and bigger the TV is, the better. And color TVs are better than black and white. This won't be a *great* Tesla coil, but it will throw a spark a few inches long and you can do all the standard Tesla coil tricks with it (St. Elmo's fire, etc.) without investing too much time or money.
Yank the flyback transformer out of the TV, and discard all its primary windings. Keep the big high voltage secondary winding (the one with the zillions of turns). It's usually encased in rubber and may look like a big rubber wheel. Its main lead has really thick insulation and connects to the side of the picture tube (where it looks like a stethoscope). The other lead (the ground) won't be as heavily insulated.
The only other parts you need are two NPN power transistors (2N3055), two 5W power resistors (20 ohm and 200 ohm), some wire, and a good supply of DC current (12-24 V). The circuit is a piece of cake. The first time I did it, I put the whole thing together with alligator clips.
This circuit has two primary windings around the flyback transformer core. The power winding is 8 turns, with a tap in the middle. The feedback winding is smaller (4 turns), also with a tap in the middle. The power winding leads connect to the collector leads on the transistors, with the center tap going to the +24 V DC power source. The feedback winding leads connect to the gate leads, with the center tap there going to +2-3 V DC (connect the resistors in series across the DC power to get the lower voltage in between). The emitter leads are grounded.
As current flows through one transistor, the changing field in the core induces a voltage in the feedback windings that turns that transistor off and the other one on. Then current flows the other way, and the same thing happens in reverse. So the circuit tunes itself to the proper frequency. But it also means that the first time you power it up you run a 50-50 chance of connecting the leads to the wrong transistor gates, in which case you get a stable DC circuit. So if it doesn't work the first time, try exchanging the gate leads.
This circuit is fairly well known, and doing a Google search for "flyback" and "Tesla" I found a schematic for it right away. The guy mentions on that page that the transistors get really hot and he is not kidding- they do. Don't leave it running for more than a minute without a heat sink. The RF noise generated by Tesla coils is incredible so expect to generate some interference. They make lots of smelly ozone. And if you let a spark go through paper, you can start a fire so be careful.
If you're lucky you can get 20-30 kV, which throws a purple spark a couple inches. (I only got about 4 kV out of mine- the spark was about a half inch long.) Pick up a neon bulb when you're at Radio Shack- these light up if they're around. The effect on a candle flame is interesting. Don't stick your bare finger near it because the spark does hurt if it hits unprotected skin. But if you hold a metal object and use that to touch it, you don't feel a thing (it's high frequency AC). Cool tricks include having sparks jump from the coil to a metal object in your hand, having sparks jump from a metal object in your other hand to ground (even a lousy ground), and having fluorescent tubes glow softly if you hold them in your other hand. If you touch one terminal of a fluorescent to ground then it will glow brightly between that end and the place you are holding it, like there are Orcs nearby.
A less extreme way is to dissolve as much salt as you possibly can in a pint of milk - you can't detect it by smell.
If you are interested in the picture on the website, here is an additional photograph of Tesla himself in the same pose, only his coil is giant-sized, and the arcs fill a warehouse. He is sitting reading a book under the giant coil with the million-volt sparks fly overhead.
Note that for this photo to work, it had to be reexposed several times for all the lightning forks to be catptured (and he sat at the end).
Picture of Tesla under his giant active coil
The noise genereated from the coil in the photo could be heard 10 miles away.
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Cast a Cold Eye
On Life, on Death
Horseman, pass by
--W.B. Yeats' gravestone