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Lightning On Demand 165

Effugas writes "The technology isn't new--Tesla coils have been around for a century. However, I doubt very many of us have seen much like the pictures located at Lightning On Demand--consider that, for most of these displays of extreme electrical discharge, there's a guy sitting *inside* the main electrode. I'm trying to imagine sitting in a metal ball while thirty foot electrical streamers erupt around me. Got Drool? "
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Lightning On Demand

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  • Thor was the god of lightning, not Zeus

    matisse:~$ cat .sig
  • Actually, a Tesla coil produces longwaves (below 500Khz). Interestingly, it tends to not harm a person, other than removing hair. It makes for really great demos where you hold a neon tube in one hand, and a tesla coil output in the other.

  • by javac ( 21689 ) on Sunday November 07, 1999 @06:56AM (#1554651) Homepage

    After reading the excellent book Tesla last year I feel that Nicola Tesla was the Linus Torvald of the 19th Century.

    Direct Current power was king. Thomas Edison's company was lighting much of the country with his D.C. lightbulbs. A young eastern european came to work with him. Nikola Tesla. Tesla was an EE genious. Tesla told edison about his Alternating Current power and how it would change the world, edison brushed him off and cheated him out of money.

    Tesla had a renewed vigor to use his AC current so he went around looking for someone to support him. Finnally he found someone in Mr. Westinghouse. Tesla worked night and day for years perfecting his A.C. power, until it was ready for primetime.

    He had an exibit at the World Fair in about 1892 I think. His amazing projects were the highlight of the world's fair. People wanted his A.C. power. However, this is when the smear campaign began. Edison knew that A.C. was better than his D.C. for general use, but he was ready to anything to stop it.

    Edison, and people from his company would go to cities that were thinking about adopting A.C. power and electrocute a couple of animals with high voltages, to show them how dangerous this, A.C. power was. They were probably the first FUD masters.

    In the end the better technology won out. But it was long and hard. People don't know about Nikola Tesla, even though he is responsible for almost every thing related to electricity in our lives. Everyone knows about Thomas Edison. But look who won


  • At this point, be sure to wear some good safety glasses as parts will fly at high velocities. Drop an old integrated circuit between the two plates and watch it explode. Great fun to show off as it makes the loudest bangs while pelting everyone with the flying pieces.

    I've heard that similar (maybe less powerful) pyrotechnics can be seen by incorrectly connecting an ordinary AT power supply.

    It was either connecting the pair of power connecter to the motherboard the wrong way (black wires on the outside, rather than together on the inside) or by connecting the power supply to the power switch in the wrong way. I can't remember which.

    I've never seen it myself so take this with a grain of salt.

  • However, it is Zeus who is/was commonly portrayed throwing "thunderbolts".
  • Except that one of the tennants of alchemy, lead into gold, is subatomic, not atomic. I doubt that nanites can be made to operate on a subatomic level.

    (If they COULD be however that would be very very cool....)
  • Even if the EHT doesn't get you, there's always the UV and the ozone.

  • watch them jump all over you.

    Sorry to disappoint, but that's just electrostatic attraction 8-)

  • AC is more efficient for carrying over powerlines but it cycles at 60hertz which is perfect if you want to stop someone's heart.


    Your comment about power transmission is correct, but AC is MUCH safer than DC, the main point being that since AC alternates and gives you some (limited) ability to pull away. Grab on to a 120VAC (RMS) line, and then grab on to 120VDC. Which one can you break free from? AC.

    AC also travels over the surface of a conductor (known as the skin effect), while DC utilizes the entire conductor cross-sectional area. The depth to which AC penetrates is dependent on the frequency. All this makes AC burns less harmful than DC burns, but a burn is still not a good thing to be going about and getting for yourself. :-)

    To rebutt another poster's comment about being able to "feel" 5VAC more than 5VDC... If I take an instrument and apply 'x'N of force to your arm, then take the same instrument but apply the same force, alternating between 0.707xN(1) 'in' and 0.707xN 'out', which will you feel more? Right, the latter. The body senses change much better than a precise amount.

    (1) - why 0.707xN? because that's the equivalent 'static' pressure, known as RMS. i.e your 120VAC power lines are actually somewhere in the area of 178VAC peak-to-peak, but the actual electric 'force' is equivalent to 120VDC. It's the same reason why speakers and amplifiers are usually measured in peak watts, because the number sounds higher and you think you're getting a more powerful product.
  • > I've heard that similar (maybe less powerful)
    > pyrotechnics can be seen by incorrectly
    > connecting an ordinary AT power supply.

    It could be the electrolytic capacitors blowing
    up. If you connect one to wrong polarity, it WILL
    blow up. And produce toxic gases so I don't
    recommend experimenting indoors.
  • ...by all means go for it! Almost all parts can be had at Home Cheapo - except for secondary magnet wire and a neon sign transformer. Lots of people use PVC pipe (altho lossy), some al duct bent in a circle for the top toroid corona discharge terminal, 1/4" copper pipe for the primary - a good capacitor can be made from a roll of al flashing ($12 for 50' x 12" or so) and sheets of poly (thickest they have, 6mil, use about 6 sheets between plates for 18Kv dielectric) - plus TONS of info on the net to design by - that really helps in tuning, which is key to getting max spark. Mine currently only gets a lousy 7" spark but working on it - still fun for zapping AOL disks etc and general night time light show.

  • >Promoting better living through mass exections of Stupid People(tm).

    last one out, please turn off the lights :)
  • regardless of what he does/did, i don't see the point of having him die... maybe i'm just turning soft
  • Tesla coils kick a$$. That guy should sell tickets. I bet I'm not the only one who'd pay to sit in that cage. :)

    I've often wondered what things would be like if Tesla had been taken more seriously in his time. Anybody know of any good Alternate History type SF based on his stuff? I've read some bios and a biographical novel about him, (by Tad Wise? IIRC.) which was pretty good, but havent really seen any SF.
  • No, the guy in the cage is shielded by the metal; however, I am wondering about the ozone? The thing must produce a lot of ozone -- Mightn't he need a respirator?
  • Sorry, it is absolutely not a dummy. Greg Leyh is a friend of mine, and runs LOD. He's been in the terminal during public runs that I've attended, at places like the Phoenix Ironworks several years back and at Hunters Point Naval Shipyard.

    He isn't the only one, but I haven't been up myself.

    I have been musing for years on how to help him build "the Big Coil", which he refers to on the web pages as the Advanced Lightning Facility. At 3-5 million dollars, it seems like something within the range of a charitable organization. Heh heh.

  • I'm wondering if that refers to the SRL Shock Box that was shown at an Artspace installation several years back. Basically a huge capacitor with exposed plates, you could throw metal objects (cans, etc.) at it and it throw them back. (Actually, the can would short out the capacitor, some of the metal would vaporize and propel the can back, more or less.)

    Moderately cool, but the Electrum (Tesla Coil) was way better.

  • It was the coolest thing I have EVER seen.

  • If you ever get a hold of a 2uF capacitor or greater that can take about 8KV, try it. Just charge up the capacitor with the two charged plates parallel and just close enough...

    At this point, be sure to wear some good safety glasses as parts will fly at high velocities. Drop an old integrated circuit between the two plates and watch it explode. Great fun to show off as it makes the loudest bangs while pelting everyone with the flying pieces.
  • Actually, removing hair like burning it off (only the hair, the process is painless). It's effect is very localized to the area where the corona touches your skin. I'm surprised that women don't use the effect instead of hot wax and such. It will grow back the same way hair that is pulled out will. I tested that on a small spot on my arm.

  • Electrolytic capacitors, even the real small ones, start to draw current when polarized the wrong way. They will start to heat and the pressure of the oil electrolyte will compromise the aluminum can in a sudden release that most people call a loud bang.

    Toxic? The oil isn't that bad, but any aluminum oxides, if any is liberated from the plates, can cause nerve damage. It would take some serious pyrotechnic temperatures to get that bad.

    Bias a small 1uF capacitor with 50 volts and wait a few minutes while it builds pressure from the heat. The little ones make great bangs too!
  • Imagine, if you will, Bill G and the boys sitting around a Redmond conferance table for an emergeny 'sunday brunch' to discuss the DOJ FOF. Bill is over in a corner littleraly throwing a temper tantrum, whailing around on the floor, asking for his mommy, saying "the DOJ is a big ol' bully, make it stop mommy"

    Meanwhile, over at a the Lightning On Demand [lod.org] web site, a very pissed off Marc Andreesen enters the address of the Redmond conferance room into the Electrum 130kW LOD web site and ZAP! Bill G. is struck by lightning.

    I can dream, can't I? :)

  • An instructor explained that 120VRMS AC is effectively equal to 120VDC in terms of TBP (Tongue Burning Power.) His explaination was that a 9V battery placed on your tongue would have the same effective tongue burning power as 9VRMS off a transformer. They would feel the same.

    About which is safer to grab on to, I'd rather be zapped by a cattle fence that had AC than DC. The AC may be a lot less likely to force my hands to squeeze a grip and not let go.
  • where are the pictures of edison with the dog(s)?
  • Exactly. I think you and I are on the same side here. :-)

    speaking of fences... my last gf lived beside a farm and her and her sister were in the backyard with me... I whispered to her sister, "Wanna see something cool?" Being 10, she nodded vigorously.

    I grabbed Heather's leg with one arm, and the fence with the other... She was in bare feet and I never saw someone jump like that before in my life...

    ... I don't think she spoke to me for the rest of the day, either... I, on the other hand, had earned her sister's total and unconditional respect. :-)
  • I can't believe I forgot to link in this psychotic [lod.org] little page on their site. These guys have actually hacked together a Taser Gatling [lod.org] gun using their prodigious electrical skills.


    For people like me, who grew up in Northern California and walked outside a few months back in slack jawed amazement for his first exposure to a lightning storm, mass electrical generators of any kind are damn cool, simply because we don't get much of that around here.

    The equivalent, of course, is when you take someone from the east coast, or the midwest, and toss a 5.0 quake at them. No big deal to Californians...Armageddon to everyone else ;-)

    Actually, there are some very, very cool tricks that can be done with static generators. When I was very young, we picked up a "negative ion generator"--essentially a device that used some technology to create a standing static charge. Connect the leads to a big metal bowl, fill the bowl with flour or salt, and as you move your positively charged hand into the bowl, negatively charged particles literally fly onto your hand, (I assume) electrostatically coating it. Fun for the entire family.

    Nothing, of course, like being in that metal cage. My god! That thing was built in my hometown! How could I have never seen it :-)

    Yours Truly,

    Dan Kaminsky
    DoxPara Research
  • Goto Home Depot near Boston...
    Thats where I met the guy who MADE the Tesla coils
    at the MOS (one of them)...got to go to his
    basement and see some of his cool stuff.
    (Half wave coil, tube coils he was working on,
    an Electical pole transformer....)
  • Redmond, here we come... (just kidding, kinda...)

    Seriously tho, the Statement of Intent [lod.org] impressed the heck out of me... Seems like it would have been something simpler, like "WE WANTED TO BLOW SH!T UP! yeah baby..."

    What I really love is the "all natural" Electrum Project [lod.org] in which 'The viewer is bathed in the raw force of nature.' Yeah... be bathed in a pile of their own sh!t if they're not careful.

    The big question? Can Uncle Billy run 300 feet in the time it takes that thing to arm?

  • I love Tesla Coils...however...

    They do not produce "Lightning", they can NOT be
    used for "Lightning suceptability tests".

    Lightning is STATIC electricity Discharge from clouds. Lightning CAN be simulated by a Van De
    Graff Generator.

    Tesla coils put out discharges of High Frequency
    Alternating Current. There are some MAJOR differences.

    Alternating current exhibits a skin effect.
    You can put your hand in the discharge of a tesla
    coil (assuming its built right). The energy is of
    such a high frequency that it goes AROUND your
    skin, and does not penetrate the body deeply
    enough to activate pain receptors, much less
    stop your heart.

    If the power output of the Tesla coil is high
    enough, it still wont stop your heart...instead
    it will cause RF burns (kind of equivalent to
    sticking your hand in a microwave).

    Static electricity on the other hand will never
    give you and RF burn. It will however also not
    exhibit a skin effect, and will happliy travel
    through your pain receptors, heart, and wherever
    else it damned well pleases.

    This is not to say that their facility will be useless. It certainly could be used to test
    aircrafts suceptability to high energey, high
    frequency energy discharges.

    Afterall, these things CAN transmit real power.
    (There is a story of a person who was working on
    a tesla coil in his basement...and a coat hanger
    upstairs turned out to make a nice antena, and a
    weater ont he hanger started to smolder, luckily
    someone upsteairs smelled it and caught it in

    hmm... I have to wonder...
    With a Tesla coil, capable of creating husge plasma discharges...an laser... I wonder if a
    small laser could ionize the air enough to get
    the tesla coil to do the rest of the work of
    turning it into a conducting path....and then
    a van de graf or taser to send a disabling
  • ...but fun too!

    Ranks high in my book of fun-things-to-do along with RC5 =)

  • It's been quite awhile since physics class, so my recall may be a little fuzzy here...

    But wouldn't the sphere of that tesla coil function as a Farraday cage for anything/one inside? I'm not 100% sure, but I think I'm right here.

    If so, why is it shocking (no pun intended) at all? The guy would've been 100% perfectly safe.

    Not that it doesn't still make quit a spectacular picture tho...

  • "Consider that, for most of these displays of extreme electrical discharge, there's a guy sitting *inside* the main electrode."

    Okay, how many people really trust Faraday that much ? :-)

  • LOL... I did check out the lightening show at the Boston Museum of science a few years ago, but I suspect that my experience was a bit different the yours!
    Do you remember the part of the show where the 10 foot tall muppet-thing rises up out of the box? It was supposed to demonstrate some principle of electricty or other, probably grounding but I'll never know for sure because something went horrible wrong. What did happen was that a huge bolt of electricity shot out and damn near blew the puppet's head off, and the puppet collapsed to the ground. This was of course followed by the cacaphony of a couple of hundred six year olds screaming in mortal terror.

    I don't think this reflects well on my ethical development, but I have to admit I was laughing so hard I was crying...

  • "Consider that, for most of these displays of extreme electrical discharge, there's a guy sitting *inside* the main electrode."
    Okay, how many people really trust Faraday that much ? :-)


    Yours Truly,

    Dan Kaminsky
    DoxPara Research

  • From the site:

    "Real lightning , which is very rarely seen up close, has the ability to focus and clear the mind."

    Uh, yeah. Last time I experienced extreme electrical discharge in close proximity to my person I had the following sensations:

    • Panic
    • Numbing of the affected body part
      (it was my hand, ok? keep your mind out of the gutter ;)
    • Singed hair
      • I did not experience any pronounced clarity of though (though I did see stars...maybe that counts).

  • Probably a railgun - which uses high voltage, large capacitors, and something called the Lorentz Force, to fire the projectile (generally a disk of some conductive material) down the rails (has to do with two conductive rails, supplying the current, and the magnetic field that is generated by the projectile that sits between them - the magnetic field is repulsed by the fields being generated by the rails, and as the projectile travels faster, the field increases - also, the projectile has to be moving before any of this happens, so generally there is some kind of launcher behind the projectile to get it moving before it hits the rails).

    Yeah, I know this sounds like bull, but it is the truth - only works at extremely high voltages, and only with the right materials for the rails and projectile (as the projectile moves down the rails, it leaves a bit of itself behind due to arcing - if it isn't moving fast enough, it will weld itself to the rails - forming a short, and probably blowing the capacitor bank in the process).

    There was a guy at DefCon 5 (went by the name of Ming - never got an email address or anything) a while back that was building a handheld railgun, used PVC pipe and aluminium (sp?) railing, and shot these special slugs he had made up - he was supposed to fire it at DC5, but he wasn't finished with it - at the time, I didn't believe the thing would even work (he kept going on about making caps using beer bottles and tinfoil - only later did I realize that people really do this for Tesla coils and other HV stuff). After doing some research, it seemed like this guy actually had something - however, I never heard what happened with his device or anything...

    Anyone know?
  • When they built the World's Largest Tesla Coil [lod.org] for some sheep farmer in New Zealand last March, they tested it at an old Naval yard at Hunter's Point in San Francisco, and sent out an invitation to the public to watch. It was incredible! Seeing the lightning come out of the thing, shoot out forty feet, and then just... hang there, seething... The central shaft of each lightning bolt looked solid, it looked like a physical thing you could reach out and touch.

    When the mad scientist running the show got inside the cage at the top, he first said, ``and now we're going to have a highly graphical demonstration of Faraday's law.'' He said that he didn't think anyone had ever been inside a running Tesla coil before, because nobody had ever built one large enough to get inside of before. Afterward, he said, ``I feel odd, but it's not entirely unpleasant.''

    (This is why I like San Francisco. ``Hey, let's go check out the World's Largest Tesla Coil tonight'' just isn't the kind of thing you're going to hear in other parts of the world.)

    Another interesting site is www.austinrichards.com [austinrichards.com]. I think this was the guy at Burning Man [burningman.com] this year who had a tesla coil mounted on top of a delivery van: he was standing on top of the truck wearing a Faraday suit and waving a metal rod around, letting the lightning hit him directly, the whole time shouting through a loudspeaker, ``I am Doctor Megavolt'' or something like that. It was sublime.

  • by MrP- ( 45616 )
    but this is better:

    http://www.netcomuk.co.uk/~wwl/electri c.html [netcomuk.co.uk]

    $mrp=~s/mrp/elite god/g;
  • This reminds me of the Boston Museum of Science [mos.org]'s Theater of Electricity [mos.org]... very neat.

  • YES!

    This thing is amazing! I saw it once when I was but a mere lad and it left quite an impression on me. The great thing is that when they do the demostration and explain about their van de Graaf, they mention that it is running at only half-power (they removed one of the belts or something). I'd love to see that sucker running at full-force!
  • I'm not abdicating Mr. Gates death, just a few millions watts of power in a directed lightning strike ;)

  • On a slightly less dramatic scale, I built a working Tesla Coil for my seventh-grade science fair project. It's easy. It had a neon transformer (from neon signs), a huge homemade capacitor built from a sheet of glass (about 2'x2') covered with aluminum foil on both sides, a homemade step-up air-core transformer (don't remember the exact winding ratio), and a spark gap made from two nails hammered into a piece of wood (with adjustable spacing). It kicked Ass! It made the loudest sound I've ever heard and the light show of electrical discharge was fantastic. I've never had such an emotional attachment to any piece of hardware since (until I got my first computer of course).

    I loved scaring my mom half to death by holding a screwriver in my hand and placing it near the transformer. Brilliant sparks would shoot over to my screwdriver and I would laugh hysterically with glee (head tilted back revealing all my baby teeth) as the surge of electrical power coarsed over my skin (the reason it doesn't hurt you is because at high frequencies, electricity travels over the surface of the conductor, which was ME!). I can't believe my mom never actually fainted.

    When science fair time came around, I can't quite express the jubilation of being in a room with all these other lame projects like "How music affects plants" and "Why recycling will save the world" and then flipping that switch, causing a sweet symphony of girlish shrieks to echo loud and far. The power to make people shit their pants. Now that's REAL power!

    If anyone wants, I can post a few pictures and directions on how to make one. However, please be careful. I don't want to be responsible for anyone electricuting him/herself. On second thought, maybe I shouldn't.
  • Did you see the one with styrofoam peanuts? They stick to the walls for up to 16 minutes. Sounds like a fun prank, to me.... :P
  • There's a book called "The Prestige" by Brit writer Cristopher Priest. It deals with two feuding magicians at the time Tesla was around and in one section the one goes to Tesla to get help with an illusion he's designing (which uses electricity obviously). Anyway the parts with Tesla in his lab are really cool. Check it out!
    "To create an apple pie from scratch, you first must create the universe." -Carl Sagan flifson@csdotuctdotacdotza
  • I'd post under an AC if I posted something like that.

    Why's that? Are you suggesting he was trolling? That account occurs in at least two of Tesla's biographies.

  • I am preparing a web page showing my homebuilt tesla coil. You will be able to find it at http://cml.grc.nasa.gov/~chuck/tesla.html [nasa.gov], but it's not finished just yet. I hate to do this, but I have to boot into Win95 in order to use my Snappy video capture (I already complained to http://www.play.com [play.com] about not having a Linux driver, but it did no good and I'm too cheap to run out and buy a real video capture board). I'll put up some pictures showing my setup along with a quick and dirty explanation. By today's tesla coil standards, this is about the simplest and crudest design possible, but it does work. I know there are much better designs out there, so if you want more sophisticated stuff, do a google search.
  • Thank you! :)
    "I already have all the latest software."
  • Although the peak operating power level of a Tesla Coil is high, the coil is not on all the time. Total energy consumption, and not peak power, is what consumes prime energy resources such as coal. Integrated over a month, Electrum uses far less energy than your computer monitor.
  • The answer to this is twofold. "Sparky", our faithful mascot, is often included in some of the tests in order to provide a sense of scale for the photo. Although he dresses nicely, he does not consist of any appreciable biomass, but rather some marginally flammable plastic. The fellow in the sphere however _is_ made of biomass, and performed several useful measurements of the streamer base current with no apparent physical harm. Whether he's a dummy or not is another issue...
  • The Legion of Doom folks are actually our next-door neighbors in web-space, at www.lod.com. Check them out.
  • Although the initial voltage source for lightning is generated by static electrical action, the lightning discharge itself is _far_ from a static process. The strike advances towards the ground in small, distinct steps called 'stepped leaders', which have oscillation time constants of tens to hundreds of microseconds. The return strike is closer to direct current in nature, and typically peaks around 2o,ooo Amperes. [See 'Lightning' by Uman, Dover books, circa 1969] The ALF (www.lod.org/alf.html) will attempt to simulate both the advancing stepped leaders [tower oscillating period ~90uS] as well as the return strike [bootstrapped DC capacitor bank in secondary ~2oo,oooV, 5,ooo,ooo Joules] to re-create long power arcs, similiar to a small multi-hundred foot section of their natural counterparts. It's not a perfect re-enactment, but it is repeatable, and should be vaguely controllable.
  • you cant electrocute yourself unless you have significant power in there -- and you probably didnt...those amps need to be in there somewhere to do any real damage. post up the details -- its fairly interesting stuff.
  • AC is more efficient for carrying over powerlines but it cycles at 60hertz which is perfect if you want to stop someone's heart. Old Tommy was frying those animals for a point, though I'm sure he cared more about royalties than anything else.

    Thanksgiving tip : 1kV for every pound of Turkey.

  • oh, in that case, nevermind. sorry
  • I'm glad to know someone can do a web search for the word 'Tesla' and they might not get a story about time travel or big-haired rock bands.

    "The sign on the wall says 'Danger 100Kv.'"

  • It's not really alternate history, but Tesla makes appearances in Spider Robinson's "Lady Slings The Booze" and "Calahan's Legacy". Mostly in "Lady Slings The Booze".
  • Man, when I was a kid, I cringed at the Tesla coil thingy they have at Boston's museum of science.

    You mean their gigantic Van DeGraff generator [mos.org]? That thing's awesome =) I remember trips to the museum when I was about 8 years old, younger even, and getting freaked out by that thing. A couple years older, and it was a great adrenaline rush. Even today (I'm 17, btw) it's great entertainment. There's nothing like the raw power of electricity to get your juices flowing. *grin*

    By the way, that link above has some great pics along the same lines as the ones in this article, plus goes into a lot of the mechanics behind it all... check it out.

  • You shoulda seen TEsla Guy at Burning Man this year ( http://www.burningman.com ). He had a big UPS style truck with a large tesla coil mounted on top. He was wearing a cage suit and the truck would drive around with him on top playing with the tesla coil. Your hair would stand up from 15-20 yards away.

    It was awesome to see this monstrosity driving around the desert in the middle of the night with the crackling of lightening as the guy sticks his head forward and gets the coil to drop a bolt directly to his head.

  • Ok, so we have Tesla and Edison being compared to Torvalds and Gates, but what about good ol' Steinmetz? He must be along the lines of Ken Thompson in this comparison. It seems no one here can remember the guy who made Tesla's AC power possible.

    He actually did make a lighting machine in 1921. Apparently, he could aim it, and admittedly, I'm no electrical engineer, but from what I've read, I think it can take about the same levels of electricity that are being spoken about here. It was designed to emulate natural lighting.

    Just some food for thought, I didn't see anything on lod.org about Steinmetz' device, and I'm wondering if anyone knows any more about the specifics, and how well it would hold up on these kinds of scales?


  • I have heard that tesla was really wrong on a lot of things. He was really against Eistein's theories and believed in the aether wind and other theories that have pretty much been disputed. I know there are some poeple out there that still believe that einstein's theories are wrong and that tesla was and is right. He beleived the universe was filled with KE in the air waiting to be tapped and other things that people just no longer accept, well, there are still a few out there. What was so great about this man if so many of his theories were reasonably disproved. Yes, he was a leader in developing AC current but like newton, he sort of went off the edge after a while (newton believed in alchemy and other strange things near the end of his life). I guess my question is why is he so revered by people. Anyone else have some insight into this...
  • OK, I'll dig through my stuff and post the details. It might not be up till tomorrow because I've got some real work (what's that?) to finish up before then.

    However, I must still emphasize caution. The electricity coming out of the tesla coil is not harmful because it is very high frequency current, but if you accidentally touch the neon transformer that powers it, you're dead. I think the neon transformer I used puts out about 9,000 V, and since (for DC and low frequency AC) Power(P)=Current(I)*Voltage(V) and Current(I)=Voltage(V)/Resistance(R), this means

    P = V^2/R

    Which means that the power goes up with the square of the voltage since the resistance of your body is fixed. The current is thus determined by the resistance of your body, and at low frequencies, the current can be extremely high and very dangerous. If you short the neon transformer leads, the current approaches infinity, but it will eventually be limited by the small resistance of the wires themselves (but it will still be large current).

    After it comes out of the tesla coil, the voltage is very high, but so is the frequency (the high frequency is generated by the oscillation of the L-C circuit: the capacitor(C) and inductor(L)). For very high frequencies, a magnetic field is created by the rapidly varying current but it lags behind the current so that it tends to push the charge onto the surface of the conductor. This leads to what is known as the "skin effect". The instantaneous current can be quite large, but because it travels over the surface of the conductor, the dissipation of electrical power into other forms of energy (burning flesh) is minimized.
  • What was so great about this man if so many of his theories were reasonably disproved.

    I do hope you know that >99% of all the theories in history have been disproved. That doesn't mean the people who created them don't deserve some credit; discovering what's wrong is as important as discovering what's right, esp. since what former tends to lead to the latter. (In this case, theories of an aether are useful as tests of modern theories, which should have superior explanatory value. They do, so they have succeeded.)

    Aristotle was wrong about almost everything he investigated, but few people seriously ask why he is respected. So was Newton (the bulk of Newton's writing wasn't on his successful physical theories). The same could turn out to be true for Einstein (and likely will, if history is any indication).

    For the benefit of the readers, I'm skip the explanation of why no theory is true... ;-)
  • I remember in 1993 at the International Tesla Convention in Colorado Springs, they took the world's largest Tesla Coil and put into this huge stadium. Everyone brought fluorescent light bulbs to light up when the thing discharged. Now that thing made this coil look like kid stuff. :)

    Incidentally, the ITC is a great place to go if you want to meet some of the most bizzare people in scientific fields. That was the place I first met Masahiro Kahata, who went on to found IBVA [ibva.com], which is worth a look if you're interested in brain/computer interfacing.

  • Couldn't agree more. Fun though it is, you have to wonder what the point is. Once of the pictures mentions that the mains power sags up to 20%. How many tons of coal (or whatever is used to power the local power station) must be burnt to power this thing. I'm not a great lover of art, and I'm certainly not impressed with art that helps to ruin the environment...
  • You'd like Vermont, ayup. In the summer we had some storms during which the emergency broadcast services told everybody in town to unplug everything in the house and stand away from windows and walls :) that was a pretty good storm. Some of the lightning strikes were going on _right_ at ground level. If you think J. Random Storm is impressive, you ought to see what it's like when the bolt _doesn't_ originate 8 miles up in the air ;) smash! wham! explode! ;)
  • Whether or not some of his theories were proven wrong, Tesla did much more than he is given credit for. AC power is not his only claim to fame. Here is a partial listing:

    AC, high-voltage, radio communication, wireless power transmission, logic circuits, robotics, radio-controlled robotics, data encryption, satellite orbits, fluorescent lighting..... The list is actually MUCH longer than this, this is just all I remember.

    And if you don't believe me, go check up on it yourself. His prototype radio-controlled submarine droid, built roundabout the turn of the century, was really really cool.

    Oh, and Marconi was in violation of 17 (give or take) of Tesla's patents when he made his famous transmission.

  • You know what, you're right! I bet a prostitute like you does make a lot of money; and gets lots of ass too! God, why didn't I think about that. It's a shame I've been wasting my life away when I could have made something of myself like you did. Thanks for straightening me out. I'll certainly aspire to be more like you in the future, or at least I'll think about your wisdom everytime I'm constipated and pushing out that really stubborn one.
  • I absolutely MUST post on this one...

    I've played with Tesla coils for most of my life. In fact, I built a nice "little" coil that output somewhere upwards of 2 million volts. Real easy to do... pole pig transformer (those circular transformers on telephone poles, hooked up essentially backwards), a big glass plate/aluminum foil/peanut oil bath capacitor, and a beautiful 10 foot hand-wound secondary coil... what fun.

    Seriously though, some people have mentioned Nikola Tesla here. This man was far beyond his time... he was responsible for the modern electrical infrastructure we take for granted every day.

    Despite all of his inventions (he preferred the term "discoveries"), Tesla's most amazing feature was his ability to comprehend complex mechanical and electrical theories without the use of any tools.

    I'm not going to bore anyone by proclaiming how great and wonderful Tesla was. The simple fact is that he was responsible for many things we take for granted today. For the most part, Slashdot readers seem to be an intelligent bunch of people... please, for the sake of justice, find out more about Tesla and help Tesla to become a household name, as it rightly should be.
  • That is just stupid. Anybody who knows the first thing about electricity knows NOT to connect a battery to AC, ESPECIALLY 220VAC. It's kids like you who made it hard for people like me to do cool stuff with high-voltage when I was a kid (and I was ALWAYS careful, and RESEARCHED what I was doing... What a concept...).

    And, at the risk of getting this post moderated into oblivion, anybody who would smash an SGI monitor just to see the sparks deserves what he gets from such blatant stupidity. (Hell, anybody who would smash an SGI monitor for ANY reason...)

  • by plopez ( 54068 ) on Sunday November 07, 1999 @10:36AM (#1554738) Journal
    I wonder how long it would take that thing to
    cook a frozen convienence store burrito.

    Just a thought.

  • (newton believed in alchemy and other strange things near the end of his life).

    Newton had always believed in alchemy, and not just towards the end of his life. I don't think this is counts against him (like many people do), but rather, is a sign of his greatness - he was willing to explore areas that other people thought were absurd.
  • I read a book called "The man who tamed lightning". I believe this is the same person you are referring to, but it's almost a decade since I read it...

    Anyways, the one thing I _DO_ remember is how it worked (what does that say about me? I don't think I even want to think about that one...). Anyways, basically it was a huge conventional transformer and a mess of incredibly big capacitors.

    When switched on, the transformers would charge the capacitors. When the capacitors reached full charge, the spark gap path would ionize, and the entire charge would flow through the air (a space of a foot or two if I recall correctly). The model town that he put in there for show was instantly vaporized.

    I think that's what you meant. On those types of powers, the capacitor banks would take something like a 200-story building... Possible, but definately not practical.

  • "aether wind and..."

    Not really my field (i'm not a complete believer) but the Michelson-Morley experiments have shown data unaccounted for by accepted science. The uses of Aether Wind for producing rain/storms have been put to practical uses also. Can't quite recall which, but I believe it was Vietnamese government that paid to fill their water reseviour using this technique.

  • It's great to see what kind of interference coils like this can produce. If i'm not mistaken (which i probably am... :-) ) They can cause fantastic television and radio reception chaos. Just think, we could force the world to live without tv... ahhh... Or, now that we've jammed the signal, we can broadcast with our immense power and spread propaganda, leading to our conquest of earth. "BOW TO KING PENGUIN."

    on another note, i remember a time when one would associate "LOD" with Bloodaxe :)

  • Science means coming up with theories to explain observations and testing these theories against each other through experiments. Being able to discuss the history of science in terms of conflicting theories, and understanding the thought processes behind each of the theories, gives us a better understanding of the theories that are currently "most correct," and allows us to continue conducting science. If we had only learned about the correct theories, how would we have been able to continue conducting science?

  • This place has some cool looking tesla coils and other electronic goodies for sale (anyone say Laser/plasma/etc...)They sell the plans or the kits or even the fully assembled stuff. Have a look... http://www.amazing1.com/tesla.htm
  • Why not aim it at deathrow in a prison on accident Wouldnt that be a site for the guard on duty. I mean imagine his report: "Today around 10:23pm (gotta be at night so we get a cool light show) all of my prisoners on death row were mysteriously killed by a large lightning bolt. Oh well." Might be a mess to clean up, but thats what we have the other inmates for. "Clean this up or you're next"
    Hell the cathlic church could claim responsibility saying "God struck down those sinners" or something and everyone could get a good laugh.

    Promoting better living through mass exections of Stupid People(tm).
  • How cool! I want one!

    Does any aussie slashdoter know if this is what they use on Good News Week? I mean, I want one...

    My neighbours get pissed off with just the stereo pumping out too much bass and I think this will piss them off even more mmwwwaaaaahhhaaahahhahaha

    Just a little one will do. I might check out what some other guy in here did as a school project

  • But now it's accepted that alchemy is possible... just not by using magic or chemistry. Nanotechnology will give us the ability to rearrange matter on the molecular level. This will almost definately NOT happen anytime soon, but it IS possible.
    Chris Dunham
  • Pictures; we want pictures!

    ...and are ya'll hiring?
  • I've thought about just what to do about the annoying Too Much Bass guy. I think that in cases where he's using a radio (for example, in a car) a focused, directed transmitter would suffice to deliver the LOUDEST possible audio pulse to his equipment. It's what I'D do, at least. :-)

    (Now, if it's a neighbour, in a house or apartment, you just kill them. It's simplicity itself!)
    Chris Dunham

  • by mcc ( 14761 )

    But while it's nice to see these people expanding so well on tesla's work with AC electricity, it would be nice to see these people looking at some of his other work. Why, for instance, have these people done nothing involving free energy, antigravity, FM radio, or warping of the space/time continuum?

    Just because the government doesn't want you to know about these important advancements doesn't mean we should totally ignore their worth while using tesla coils to blow things up. For example i'll bet a pure-space free-energy reaction would look pretty cool wth Hemos sitting inside of it.

    Just a thought.

    7H3 7RUTH 15 0U7 7H3R3!!
  • From Merriam-Webster online: [m-w.com]

    Main Entry: giga-
    Pronunciation: 'ji-g&, 'gi-

    So either pronounciation is correct. But yeah, you're right that it's 1.21 gigawatts, just pronounced the original way. Although the pronounciation as 'ji-ga' is outdated by my Webster's Unabridged Dictionary...

  • Exactly. That guy is so wired that all the electricity would be directed to ground anyway.
    "I already have all the latest software."
  • Yes, but you need a lot more of it.

    Touch your fingers between +/- 5VDC, then touch your fingers bwtween 5VAC. You definitely feel the latter. (I speak from experience. Ouch!)
    "I already have all the latest software."
  • I can't remember what it was, but I think they were trying to prove that sitting in your car during a lightning storm was the safest thing to do.

    They basically got a power cable and dangled it above a road, and got a stunt man to drive the car into it. As he touched 40,000V went through the car, but he got out fine. It was pretty cool.

    The car might have had to be moving to be safe, I can't remember.

    (Disclaimer: Just because I said he got out safe, I don't want anyone cutting power cables and driving into them, and then sueing me because I said it was okay)
  • I wonder if the guy in the cage feels OK after the fact. It's like using thousands of mobile phones at the same time, in terms of electromagnetic radiation hammering your brain.

    Humans come pretty well shielded, apparently.
  • Massive electrical charge has a well known history of clearing the mind.

    Just ask Hemingway, who suffered through quite a bit of electroshock assisted mind-clearing(he lost almost all of his memory...supposedly one of the reasons he shot himself.)

    Yours Truly,

    Dan Kaminsky
    DoxPara Research
  • 1.4 Gigawatts!

    (hehe, i wonder how doc brown would like this thing!)

  • Not me! It'd just be my luck to be sitting in that thing when the universe underwent some sort of physical law change. ZAP!

    Man, when I was a kid, I cringed at the Tesla coil thingy they have at Boston's museum of science. I still get sorta freaked when touching those plasma ball things that were such the fad in the early 90's.

    And... oddly enough... I *love* watching thunderstorms. Go figure. Controlled displays of eletricity? Frightening. Uncontrolled chaos? Cool.
  • I helped out during the 97 SRL show in Austin TX, they brought one of Greg's big Tesla coils.
    The machine was a work of art if you ever got to see it closeup. He fed it with a bank of transformers that took 440 3Phase from a 300KW generator that we rented and stepped it up to about 10KV DC . The base of the Tesla coil has a motor driving a 1 inch thick aluminum disc with large copper electrodes bolted to the rim. The 10kV was fed to a stationary electrode on the bottom, jumped the gap when the rotating electrodes aligned with the top electrode which was connected to the primary coil. The operator pedastal controlled the speed of the motor, it was really interesting to hear the pitch of sound change as he tuned up the coil to get the highest voltage for the day's humidity and other variables. The primary was about 6 turns of copper busbar about 1/2 inch thick and about 2 inches wide. Really beefy looking since it carried about 100KW. The secondary coil had what looked like 0 gauge battery cable wrapped around a spool about 15 feet high tooped with an aluminum toroid. I think Greg said he got 2 million Volts at 50mA at the top electrode. He brought that same coil out to Burning Man in 1998, it was very popular, you could hear it across the whole Black Rock City.
    The one thing that was pretty neat was that one guy at the SRL97 show built a Faraday cage suit out of heating ducts and wire with a birdcage as the helmet and he walked up to the big coil while it was running. I was filming him on his first try of the suit, you gotta trust your physics at that point... The next night they tried it again and really freaked out some state trooper who was watching from across the street. They said he came rushing over with the car lights flashing and got out of the car and started yelling at them 'What the hell do you all think you are doing!!'
    It looked like the same suit that DR MegaVolt was wearing this year at Burning Man. He was standing ontop of a Ryder truck with a 5foot hight Telsa coil and was doing a lot of stunts with the electricity as one of his minions was exhorting the gathered crowd with a bullhorn 'All hail Dr MegaVolt... Bow to the power of Dr. MegaVolt.. Give us your offerings of love and food and alcohol and other things....' The crowd would give him some offerings to be held up to the coil where the arc would make them burst into flames. Quite cool...
  • If you live in the northeast, or ever travel there, be sure to check out the lightning show [mos.org] at the boston museum of science [mos.org]. they have the worlds largest van de graaff generators [mos.org], with a guy in a cage that gets hit by bolts [mos.org]. Also, the museum is just great in general.
  • Heh, you thought just putting them in the microwave was cool, Now show what you think of those inferior OS's/ISP's Tesla Coil CD Zapping [netcomuk.co.uk]
  • I wonder if the guy in the cage feels OK after the fact. It's like using thousands of mobile phones at the same time, in terms of electromagnetic radiation hammering your brain.

    No, it's not. The cage is made of metal, and hence it is a Faraday cage. There is *NO* electromagnetic force inside the cage. Very simplified explaination: Metal is a conductor; electricity is carried by electrons; the sign of the charge of all electrons is the same, hence, all electrons repel each other. Because they repel, they want to be as far as possible from each other. Being as far away from each other as possible means that electricity flows on the outside of conductors.

    -- Abigail

  • Patience... Mr. Gates does not need to be struck by lightning. It would be too quick. The wheels of justice are turning.

    They may turn slow, but while Mr. Gates was playing with the law, he seemed to have slipped in the cracks of a large set of rotating gears...
  • Actually, whether "sparky" is a real person (which I doubt judging by the lightning through his hand) or not doesn't really seem to matter. He can't be inside the Faraday cage. The fluorescent lightbulb around his head is lit, and as we all learned in Physics 101, there will be a net zero electromagnetic field inside the cage.

    The reason that the fluorescent lightbulb is lit is because of the stupidly huge electromagnetic field created OUTSIDE of the Tesla coil. That field will light fluorescent lightbulbs in the vicinity (an area proportional to the square root of the coil power...)

    This actually brings up a good point... Tesla himself was a big advocate for using Tesla coils to power people's lights. He even at one point built a tesla coil large enough to light an entire town (I don't remember exactly where it was.) However Tesla coils, while convenient because nobody needs silly things like cords or sockets for their lightbulbs, use up stupid amounts of electricity and are REALLY noisy. The story continues that Tesla finally finished the project, flipped the "big switch" and drew so much power that he shut down the power grids in several states.

    Just some nice, Sunday morning, anecdotal remarks.
  • Now this is the kind of stuff chicks want. Want to impress a woman? Press a button and summon a 130kW bolt of lightning, and watch them jump all over you. (After you've discharged, of course.)

    "That's right babe. Just call me Zeus."

    -- Give him Head? Be a Beacon?

  • FWIW, Greg Leyh knows what he is doing. He is a pro and isn't going to get anyone killed or blow stuff up. The demonstration with someone inside a sphere isn't as dangerous as it appears. Electricity follows the shortest path to ground. The sphere is grounded so the electricity hits it. Same things with power lines etc.. Electrum is the biggest coil I'm aware of next to the master himself, Nikola Tesla. He built a rather, uh, large facility in Colorado Springs near the turn of the century.

    I build coils as well, though not nearly as well as Greg does, so I am aware of the danger and saftey issues. I'm surprised more /. members haven't heard of Tesla Coils before. There is a mailing list w/ searchable archives at www.pupman.com. There are more pics there as well. Go see one in person if you get the chance. The pictures don't do them justice. :)
  • It's like using thousands of mobile phones at the same time

    Yes, he did feel an effect, after the exposure to the lightning he was no longer able to swim to the island in the middle of a milk pond.

    matisse:~$ cat .sig
  • Actually, its 1.21 gigawatts... the conversion is that you've probably been pronouncing words starting with "giga" wrong ever since you got a computer with a harddrive bigger than 1000 megs.

    The correct pronounciation of the "giga" prefix is "jigga". So that's a 1.21 "jiggabyte" drive you've got too...

Marvelous! The super-user's going to boot me! What a finely tuned response to the situation!