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endotherm
May 15th, 2002, 08:04 PM
Anyone in here interested in Van De Graaf Generators?
Anyone built one?
If you have no clue what they are <a href="http://www.howstuffworks.com/vdg.htm" target="_blank">CLICK HERE</a>.
They have virtually no use as a weapon, but for some reason seem very intriguing to me due to their ability to produce 10-12" spark gaps! Their concept is simple, but is it really that easy to build one? I was thinking about building a very small generator about 12" long, to produce small sparks and be portable. Any tips or suggestions?

Cricket
May 15th, 2002, 09:52 PM
I just did a bit of research on this, about a week ago. I searched at google.com and got several very useful pages. My science teacher has one and I started messing with it and I got interested. I shave my head and I wondered what it would feel like if I got shocked on my head and it hurts! The only other thing to say is, go to Jhonbus's sight, it is useful and has many links. <a href="http://www.geocities.com/jhon_bus/" target="_blank">http://www.geocities.com/jhon_bus/</a>

mongo blongo
May 15th, 2002, 09:55 PM
Have a little look at my post in
<a href="http://www.roguesci.org/cgi-bin/ewforum/ultimatebb.cgi?ubb=get_topic;f=4;t=000341" target="_blank">http://www.roguesci.org/cgi-bin/ewforum/ultimatebb.cgi?ubb=get_topic;f=4;t=000341</a>
In my first post I described a way that one could be used as a weapon.
It was just a stoned up idea I had once but I have never tried it.

AcridSmoke
May 15th, 2002, 10:26 PM
Well, I've had a bit of experience with these generators. My science teacher was sitting there shocking the crap out of her arm one day when we came in (she's kind of nuts).
This fairly small one (about 2 feet) made 4-6 inch sparks with a little dome. It ran off of a tiny motor plugged in to a wall socket.

The application of a weapon if modified to a more combat-efficient design should not be ignored, but friendly fire would be quite a problem.

edit:mistype

<small>[ May 15, 2002, 09:29 PM: Message edited by: AcridSmoke ]</small>

PYRO500
May 15th, 2002, 10:58 PM
I have one and can tell you they serve no purpose as improvised weapons, they may make pretty high voltages but their current is virtually nil, the only reasonable use for one is to charge leyden jars or electrostaitic experiments, they are fun to mess with but unless you need to charge something with static electricity then you don't really ned one of these.

A-BOMB
May 16th, 2002, 02:08 PM
Pyro500 its the intimidation factor most sheeple don't know shit so they would be scared shitless buy the sparks just because they see to many movies where people or monsters are fried with some thing like that.

J
May 17th, 2002, 05:52 AM
For intimidation, it would be easier to buy or build a stun gun. You would need an enourmous Van de Graaf generator to produce lethal voltages/currents. By it's very nature, it's voltage output is determined by its height.

Mick
May 17th, 2002, 07:08 AM
if its intimidation factor your after, buy a fucking gun.
its really that simple.

i have been interested in building a van de graaff generator for quite sometime. i know how to build one, i more then likly have the materials for building one - however its just one of those projects that never quite makes it to the top of my list.

if your looking for cool looking arc's and that sort of shit, build a jacobs ladder. i built one a few months ago, its still amazes every time i look at it. only difference with a jacobs ladder is you can't touch it and go "wow! my hair standing on end", usualy when you touch a jacobs ladder you say "wow! my chest cavity just blew open, and i have 3rd degree burns to 40% of my body, and my feet have melted to the floor!"

kingspaz
May 17th, 2002, 05:46 PM
could a tesla coil be improvised into a weapon? i don;t know much about them but i'm sure some one does...

CyclonitePyro
May 17th, 2002, 07:15 PM
You don't really build a Jacobs' ladder, you just take two pieces of wire and attach them to a transfomer so they are angled away from each other. They are neat though and would be nasty to touch.
Tesla coils are awesome, no real use as a weapon though. A friendof mine built one in school that makes 400kv sparks. Not really sparks though, just a whole bunch of high frequency, high voltage archs that go into the air and every which way. He is going to join the forum but I think has to wait for the 2 weeks. His name is McGiuver(sp?)
I thought there was someone by that name here already. Can anyone confirm this, and if he changes his name will he have to wait another 2 weeks?

mrloud
May 18th, 2002, 12:19 AM
There's lots of info at these two sites.

<a href="http://www.powerlabs.org/" target="_blank">http://www.powerlabs.org/</a>
<a href="http://www.electricstuff.co.uk/" target="_blank">http://www.electricstuff.co.uk/</a>

Jhonbus
May 18th, 2002, 02:04 AM
I have some experience building all sorts of high voltge devices, including VDG generators and Tesla coils. VDGs are fairly easy to make (I used some coke cans as the top terminal and a rubber band for my first one) This gave about 2" sparks about every 10 seconds. The thing was about 1 foot high, maybe a bit less. I tried to build a bigger version, but I couldn't get anything suitable for the belt.
Neither Tesla coils or VDGs would make a good weapon. If you somehow managed to attach a TC to your arm or something, I think you'd be more likely to shock yourself than anyone else, and the range would never be more than the distance to the ground. (ignoring laminar argon streams or UV laser-ionised air channels.)

PYRO500
May 18th, 2002, 11:14 AM
As a matter of fact I am a member of the powerlabs message board, they are more diverse than us when it comes to general science and electronics. as for using a VDG I would say definitely not but a tesla coil (I am currently collecting parts for one) can be lethal but again the device will not behave in the manner necesary to do what you want, I have herd of people trying to use argon to draw sparks but their results were that they only managed to get the arcs to travel about a foot or two in that direction. Now, in a reduced atmosphers eg, space for example you could put one of these to use in destroying other space craft but you got to get there first :) .

AcridSmoke
May 19th, 2002, 05:13 PM
Hmm, I just had an idea...

What about something with either a Van De Graff or Tesla above a doorway, facing downwards? It would probably be a suitable theft-deterrent mechanism, but not lethal. Charge it up at night before you sleep (or whenever), and then let it sit until someone steps within the range of influence. Then, they get a painful shock of electricity to the head or face...

Just an idea.

PYRO500
May 19th, 2002, 10:10 PM
That won't work beacuse neither will hold a charge for that long, the van de graff will loose it's static charge very fast after discharging and even if one that was that small was left on continuously it wouldn't hurt that much. a tesla coil is not designed to hold a charge either being a resonant transformer it will not have any charge after turned off

photonic
May 29th, 2002, 02:10 AM
Tesla coils could definately be used to kill something. I suppose they're not too useful in the field because they will "zap" anything that walks by. The arcs from tesla coils are in the megavolt range. Read the safety data at <a href="http://www.pupman.com" target="_blank">www.pupman.com</a> to see why they'll kill you. I too would like to build one and am collecting the parts for one. If anyone knows a good source of large amounts of inexpensive bare copper magnet wire, I would love to know as this is the main component keeping me from building one. After I'm finished I'll videotape the rats in my attic being cooked and that'll give you some idea of what that much energy will do. Anybody know the approximate current through the body from a tc? I suppose a tc
would only be practical as a defensive weapon.

<small>[ May 29, 2002, 01:12 AM: Message edited by: photonic ]</small>

nbk2000
May 29th, 2002, 05:31 AM
It'd seem to me that a simple high voltage neon transfomer would be adequate for a lethal electric barrier.

Imagine a bank a high capacity capacitors charged with several thousand amps of juice. These are connected to a "bead" curtain where the string is actually steel cable with small fishing hooks on it, and the area around the door threshold has a copper ground plate underneath the carpeting.

When some intruder passes through the curtain, it snags on them. The pulling of the cables causes a state of change in a motion sensitive switch on the curtain, triggering the capacitor bank to discharge a hugh amount of lethal amperage through the intruder into the ground plate.

Or the neon transformer hooked to a wall socket would fry them too.

VDG are static electric generators. Painful, but not lethal in realistic sizes. Teslas are complicated and expensive.

Mick
May 29th, 2002, 12:25 PM
it would be much easier to simply install a door with 2 door knobs.
then hook the NST to door knobs. that way when they try to open the door they have to complete the loop.

also, i think people would see the little fish hooks hanging from the beads. in which case it would be easier to omit the presure switch and all that, and just hang some thin steel cable, because as soon as it arcs to them its going to stick to them. or if te steel cable was to obvious you could use some stainless steel fishing line and then put the beads back on, only use chrome plated type ones because i'mm pretty sure they conduct electricity - if they don't, just use little hunks of charcol every few beeds.

PYRO500
May 29th, 2002, 03:27 PM
you don't want a NST to fry someone, they don't put out a whole lot of current, sure they give you a good jolt but will not deter everyone(I know beacuse I have several). you want a microwave oven transformer, most of them give about 2000V at half an amp that is 1,000W at enough voltage to overcome skin resistance, in the reapair industry we consider them one touch lethal in that you NEVER want to touch one beacuse they kill easily due to the high wattage.as for a capacitor bank they sound like a good idea but aren't practical due to the necessity of having to be charged and the real high energy ones aren't designed to hold a charge for a long time. The dielectric in these mammoth caps will quickly tear itselves to peices if they are holding a charge for a long time. also you need a relitively high voltage to have one discharge through the skin rapidly and ensure lethality. In the case that someone were to use a very large pulse cap say 7000J at 10,000V (140uf) a person coming in contact with the capacitor would pretty much be ensured an explosive amputation. I remember when I was 12 I had a 700J capacitor bank and built an action figure electric chair out of popsicle sticks with little bands of Al foil on their heads, I closed the switch and their head got burnt with the vaporized Al foil, how about a full sized version except no foil? think they complain about the chair not being humane enough now...

Mick
May 29th, 2002, 07:03 PM
"will not deter everyone."

wtf? of course its going to deter people. if i get electricuted i'm not about hang around.

also, i reckon it would kill you, because its going to force you to hold onto the door knobs which means your going to be stuck there for a reasonable ammount of time..

either way, i'd hate to be the poor cunt holding onto it.

PYRO500
May 29th, 2002, 08:17 PM
Nah, a neon sign transformer will probably arc to your hands before you can grab on to them, electricity can arc about 1.1 mm per KV so 15,000 would be 16.5 MM and you would get kind of a burning shock but you would pull your hand back very fast and not do much damage, ifd someone suspected that way was boobytrapped the certainly would avoid that way they'd either kick in the door or find a window or something, electricity can cause you to hold onto something but something as low current as the neon sigm transformer will only be a deterant, if you want something high voltage that would work fairly well and kill would be a pole transformer (pole pig) hooked directly to the mains and to the door, now you want to avoid arcing to the door jamb so get rid of the metal lock cover and any wiring near it and also you need to make this thing so it won't canstantly arc at the some 28Kv it may put out so you mod a capacitance door alarm (little things that have wire that loop around metal door knobs and wire it up so that when the door is touched the transformer kicks on with the BIG relay you have and arcs to their hand, that would be like touching a powerline and would likely kill the person due to internal burns not to mention other complications such as fibrilation.

just make sure you don't get near it cause if you do it may likely be your last.

nbk2000
May 30th, 2002, 02:31 AM
The hooks are at the bottom of the strands since they'll catch the legs without being readily visible like at eye level. Once snagged, they're fried.

Whatever you use, it should have sufficient amperage to "lock" them in place so they don't let go/jerk away. Once frozen in place, they deep fry inside till they're dead.

Microwave transformers one touch lethal? Cool. Plenty of those around at junk stores waiting for use.

Good idea about the capatitance switching to prevent arcing before the victim gets locked on by the voltage.

If I'm not mistaken, you can build high voltage capacitors from glass bottles and foil that'll hold lethal high amp/voltage charges for days (dry air). In the AmSci CD somewhere.

If all you have is a NST, that'd still be enough to rock their world. And no reason why it can't kill if you arrange it so that the shock causes an "accident". Like if you had metal handrails on a staircase/ladder with breakbeams/switches to energize the NST when they're near the top. They shock stuns them and causes them to fall down to their death.

I've heard of people getting caught in coils of electrified razortape while trying to sneak over a border. Even when the voltage isn't lethal, the fact that they're getting constantly shocked jerks their body around inside the razor coil, causing them to get shredded and bleed to death from hundreds of lacerations.

"explosive amputation"?! <img border="0" title="" alt="[Eek!]" src="eek.gif" />

Think you could build a baton device that'd be safe to handle that could dump that kind of charge on contact? Now THAT'd be something to have at night in the back alley. <img border="0" title="" alt="[Wink]" src="wink.gif" />

Bum:
"Hey man, can you spare a buck?"

NBK:
"Get a job or get a gun you fucking bum!"

Bum:
"What?!"

NBK:
"Quit begging! Makes people hate you."

Bum:
"Fuck you!"

(Bum attacks NBK. NBK whips out "Kill-O-Watt" baton)

"zzzzZZZZAP!"

Bum:
"AAAAAAHHHHHHH! My arm's gone!"

NBK:
"Punk! :p "

That rip-off scam site called "Amazing Concepts" used to advertise something similar in concept to a "Kill-O-Watt" baton. But it could only blast a pinhole through a soda can. I'd want something that'd explode the can or vaporize a fist sized chunk of flesh on contact. Oh, and rapid recharging(<3 seconds) from batteries.

PYRO500
May 30th, 2002, 03:49 AM
Ha! a baton that has that much energy in it, you'd better get a face shield :) . In reality that much energy could only be stored in a 300 pound mammoth capacitor, but if it was hidden... Those energy storage caps aren't designed to hold their charge for more than a minute or two, unless you find the perfect dielectric that can store an amazing charge in a tiny space then you will have trouble with these devices. I think a relitively powerful transformer attached to a door that is activated on touch is the best although if a person can fall when they are locked onto something there is a possibility that they may break free. I said earlier microwave oven transformers were considered one touch lethal, I ment that they are mostly fatalities when people really get a hold of them they give seriously powerful shocks and will cause internal burns easily. I have personally seen an arc from one melt glass! they can be used in parralell for more current (roasting power) although too many will trip a breaker. Those salt water bottle caps you described are far too low in energy density to be very useful and are kind of lossy and have very high esr's.

<small>[ May 30, 2002, 02:53 AM: Message edited by: PYRO500 ]</small>

Flake2m
June 5th, 2002, 11:03 AM
Couldn't a VDG or a Tesla coil be used an electronic weapon?
I am thinking that the sparks would create electrical interference that may be able to disrupt communications devices.
With some experimentation and research it may be possible to build a VDG that would create electronic interference at a specific frequency.

PYRO500
June 5th, 2002, 01:58 PM
No, you wouldnt be able to disrupt communications with one beacuse they do not resonate at any frequency, I guess a tesla coil with a spark gap and coil could but there are beter and more powerful ways to jam.

photonic
June 5th, 2002, 04:44 PM
Tesla coils are fairly inefficient antennas and therefore don't make good "jammers." I suppose if you made one with a huge top capacitance and ran it just below the break out point, it would probably disrupt some of your neighbor's TVs, portable phones, etc.. but like PYRO said, there's better ways to do it. Also, tesla coils are fairly dangerous and there would be no reason to use something that can kill you so easily just to jam communications.

McGuyver
June 5th, 2002, 08:51 PM
Actually, tesla coils jam AM raio for a radius of about 1/2 mile or depending on the size of the tesla coil, much further. They couldn't really be used as weapons except if you carried around a generator and a good ground. It is also very large and bulky, maybe some kind radio-controlled car thing driving around with an extention cord attached to it, to zap the mailman. I built one that generates 400,000 volts and makes a 12 inch(probably more) arc to a grounded wire. They also generate ozone if your interested in helping the ozone layer. :)

PYREX
June 9th, 2002, 10:16 AM
If you want to build a jammer the most important thing is the right antenna; the most powerful RF-generator is useless if you don't get that power on air. So for a medium sized tesla coil with a resonant frequency of lets say 600kHz your lambda/4 antenna will have a length of 125m (still interested?).
The next thing to consider is the tuning. As you may know the impedance of the feeding coil has to be the same as the impedance of the antenna coupled to it. A coil producing 400kV has an input power of I'd say 800W. The resulting impedance of the secondary is therefore around 200MOhms whereas your antenna has only 50Ohms. Conclusion: forget your secondary! Build a new one with the needed 50Ohms impedance@your frequency instead. This new one may not look much different than your primary.

Tell me when you've finished, I'll turn on my radio :D

PYRO500
June 9th, 2002, 04:43 PM
I think that 800W is just a guess put out there, you cannot really determine a tesla coils power by the voltage you need the current too.
While antenna selection may be important I would say that the amount of inductance and pulse with and spacing. when you build a spark gap jammer you are not simply throwing out junk you have a relitively wide pulse that has a peak at it's most powerful frequency nd covers surrounding frequencys at lower power. I would recomend a pulsed high voltage capacitor as a power source. When you pulse the capacitor through the coil you create a magnetic field and when the magnetic field state returns to zero the collapsing magnetic field creates something called EMF ringback, this is the actual cause of the jamming and is determined mainly by the inductance in the circuit. If you look at an RF tuner circuit you will see that all they are is a capacitor and an inductor. as a matter of fact you can directly determine the frequency by the inductance and capacitance in your circuit.

nbk2000
June 9th, 2002, 09:04 PM
I hold out high hopes for room-temperature super conductors.

According to an article in Science (or similar) years ago, a ring made of SC material would be able to maintain a perpetual charge of high voltage energy. They said you could pack a lightning bolt in a ring the size of a frisbee that'd weigh only a few ounces. <img border="0" title="" alt="[Eek!]" src="eek.gif" />

Now THAT would be impressive firepower to be packing! 'course the problem becomes one of how to avoid become the ground for your own lightning strike. Perhaps UV laser ionization? That'd direct a charge to a target.

PYRO500
June 10th, 2002, 12:36 PM
You just can't wait until you have your patented nbk2000 super tazer, more energy than than the z machine at sandia national labratories in the size of a box of matches. The problam is that with a higher voltage you need a good dielectric to protect you from shock witch would work as a capicitor dielectric to store your energy :rolleyes: .

nbk2000
June 10th, 2002, 10:07 PM
Nobody ever said it'd be easy (or safe...or sane <img border="0" title="" alt="[Wink]" src="wink.gif" /> ) to make. :D

10fingers
June 10th, 2002, 11:30 PM
Tesla coils are good at generating RF across a wide range of frequencies and thus can screw up TV's and radios in the immediate vicinity. The range would depend on the power and oscillating frequency. The FCC would not like these things.
A good capacitor for a Tesla coil can be made out of sheets of glass with a piece of aluminum foil in between. You also need a spark gap in the primary circuit to adjust the frequency to match the resonant frequency of the secondary. Carbon arc rods for welding make good spark gap electrodes.
Usually the primary is just a few turns, maybe 10, of highly insulated wire with the capacitor in parallel. The primary voltage needs to be high to start with to jump your spark gap, a neon sign transformer works good for this. You could use an SCR (silicon controlled rectifier) instead of the spark gap but I think the spark gap is simpler and able to withstand higher voltages. The secondary is usually a couple thousand turns of fine varnished wire. The capacitance for the secondary is formed between the turns of wire so no capacitor needs to be added.
The greatest voltage will be produced when the oscillating frequency of the primary is matched to the secondary.

PYRO500
June 11th, 2002, 05:18 PM
I don't think an scr would work very ell with a tesla coil, mainly due to some limitations they have. High voltage scr's usually have some kind of switching rate or a speed at witch they can switch witch is usually too slow for a tesla coil, they also will be subject to ringing or oscilation in the tesla circuit when the voltage is reversed, also the circuit will continuosly be conducting forward witch means that the scr will never switch off! They work good for pulsed power applications (I can attest to this) I built an em disklauncher and a coilgun out of one I have.

McGuyver
June 17th, 2002, 08:20 PM
My secondary is a little over 1,000 turns. My tesla coil uses a rotary spark gap which is more efficient than a stationary one. It's not as hard on the caps too. Tuning is very important with a TC- it will be very wimpy without it. Instead of changing the turns of wire- add capacitance- it will give you a hotter spark and a better shock :) . Also, it depends what kind of voltage you are working with but, there is a company (not sure,-search) that sells 10KV caps that work perfectly for my TC. I used 2 oil-filled ignition transformers(the kind used in air conditioners) they put out 10KV each.