Tesla coil built from trash

tesla coil

Greg Miller prides himself on his dumpster-diving ability. To encourage others to take up the terrestrial sport he developed this Tesla coil built entirely from trash (Coral cache link). The power supply is from a neon sign he found behind a frat house. The capacitor bank is constructed from high voltage caps found in televisions. The spark gap is a pair of 1/4 inch bolts. The primary coil  is formed on a lamp shade using a cord from a humidifier. The secondary coil is made from the wire of a microwave fan and a cardboard tube. The toroid, pictured above, is constructed from two stove eyes. The chokes are wire wrapped around ballpoint pens. He’s got some nice pictures of it in action plus a guide to what goodies you should salvage from consumer electronics.

[thanks Victor]

21 thoughts on “Tesla coil built from trash

  1. very cool. I had to sudy tesla’s life for a little while back, he was a neat guy.

    quick little tidbit of information on tesla:

    for his first invention, he devised a pin-wheel kind of thing out of some sticks that could spin around. he then would get flying beetles (june beetles, I think) from some kid, and glue them onto the ends of the sticks in a certain way. when they tried to fly away, it would make the wheel spin.

    he stopped using beetles when the kid that gave them to him ate an entire handful.

  2. Don’t forget that at the end of Tesla’s life he was completely alone and died with pigeons as his only friends. He also was the first to attempt developing a death ray. Very interesting man.

  3. Tesla this and tesla that. Really, he was a neat guy that many claim was seriously overlooked. As a former physics student who studied physics history quite a bit, his problem was all in timing. He was around when a lot of people like Einstein, Openheimer, and Edison were hogging all the spot light.

    This is a really cool dumpster dive project. I tried dumpster diving once and incurred the wrath of the local police…

  4. >Don’t forget that at the end of Tesla’s life
    >he was completely alone and died with pigeons
    >as his only friends.

    I think that is the fate of most of us hacker – geek – nerds. I’m already “that cat guy” that people offer stray cats to. Given a chance to do it all over, I’d gladly trade my proficiency with technology for a vacant look, a football, and a cute girlfriend.

  5. “So I’ve opted to find several relatively high voltage capacitors and link them together in series so that the voltage across each capacitor is the total voltage divided by the number of capacitors (that is if the capacitance of each capacitor is the same).”

    um. Don’t capacitors need to be attached in parallel in order to sum the capacitance? In series should yield a capacitance far lower than the lowest individual capacitance value. Right? I’d email the author but this is 3 years old.

  6. @fluxist
    It is the maximum voltage that is critical for a capacitor in this application. If you need a capacitor for ie. 1000V and you have only 500V rated ones, you should link two of them in series (or maybe three just to be sure). So in one word: serial linking for higher voltage, and parallel for higher capacity.

    @miscblogger
    use wikipedia:

    http://en.wikipedia.org/wiki/Tesla_coil

  7. @fluxist
    and if you link two same capacitors in series to double the maximum voltage, the equivalent capacity is not changed compared to one capacitor. (analogy can be applied to parallel connection)

  8. Thats not right, when you connect in series the capacity is actually reduced. 2 identicle units in series produce double the voltage but half the capacitance.

    This is required by conservation of energy. It is true to say the energy stored at peak is double the energy stored of a single capacitor at its peak (true for series and parallel).

  9. This is pretty neat, an alternative to a neon sign transformer is an oil burner ignition (OBIT) which works fairly well. Those chokes are absolutely vital, the transformer will burn out quickly if they are not used.

    Another alternative is to obtain several monochrome TV flybacks and drive them sequentially using a 4017 and driver transistors, connecting the HV outputs in parallel. This is a bit more work but does let you control the input voltage as well as allowing the whole unit to be run off low voltage (i.e. 12V) :)

    -A

  10. tesla coils are great, and everyone should play with them at least once. If you’re looking for a high voltage toy, look for Lifters (built one for high school physics project, blew away the class).

    Other interesting note about tesla- discovered a way to broadcast electricity, only it was too wasteful. We need some cold fusion, then send it all out everywhere!

  11. Ok, I have this neighbor below me who has grown trees right next to the property line. They are beginning to block my view! How could I make one of these things and then “blow” off the tops of the trees?

    Or even better, can you think of a way of making a homebuilt microwave focusing device (like a radar dish on a military plane) that I could focus at the trees and kill them from oh… say 60 feet away?

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