This device is nearly as hazardous as a soldering iron. While this thing can't shock you, it can easily burn holes in your skin with its few-watts electric arc. In other words, don't "zap" yourself on the high-voltage section, or you'll end up with a tiny black-charred pin-hole in your finger, a cloud of burning-hair scent, and a small painful burn. It also can damage medical implants, computers, phones, etc. In other words, DUH it's a Tesla Coil. Use it responsibly. Don't let it fall into the wrong hands.

2,000V, 50KHz
W. Beaty 2005

Scroll down to EXPERIMENTS

Several surplus electronics companies sell very small hi-volt power supplies called "fluorescent lamp inverters" or CCFL drivers. In fact, these devices are actually solid-state continuous-wave "CW" Tesla Coils: they produce one or two kilo-volts at high frequency.

I've messed around using the CXA2090 shown above. Although it's designed for 5VDC input (at up to 200mA or so,) actually it runs fine using a 6VDC battery pack. It even keeps working down to ~0.5V input. Most of them can tolerate a 9V battery, though some will be destroyed by this. A few can make it all the way to +15V before burning out. So, if you want to smoothly sweep the high voltage output across many values, just use a variable 1-amp DC power supply.


SOME EXPERIMENTS           W. Beaty 2012

NEEDS A 6-VOLT AA BATTERY PACK. Try 270-409 batt holder from Radio Shack
Red wire goes to red, black to black. That RS holder has a tiny on/off switch, nice.

YOUTUBE VIDEO TO COME! (Working on it right now, Mon 9/24 2012)

In a dimly-lit room, power up your TC. Hold a tiny neon bulb by both wires and place the glass part against the white HV wire. Orange glow! Wireless lighting! Wave the tiny bulb near the square transformer, and near the "hot" end of the circuit board. You can sense the invisible voltage in the space around the device. [If you donated $200 to LET'S BUILD A GODDAMN TESLA MUSEUM, look for the small clear NE-2 neon bulb in the baggie with your device.]

In a dimly-lit room, grip a standard fluorescent tube[*] in your hand and hold it a half-inch away from the white HV wire. It lights up dimly. Now touch the metal pins of the tube to the HV wire and the tube lights up quite brightly. But where is the complete circuit? Connect the HV wire to one of the tube's pins and lay the lamp tube on a non-metal table. You've made a gas discharge lamp run in "Single-electrode Tesla mode." Touch the glass and watch the plasma respond.
[*]WARNING, don't use a good compact fluorescent spiral bulb, the HV can burn out the electronics. Try it with a dead one.

Run your TC, grip a coin or metal key firmly in your fingers, and touch it gently to the end of the white HV wire. Pull slowly away, and you can draw a little purple arc between the coin and the wire ...yet you feel nothing. The frequency is far too high to trigger pain nerves (but it's too low to produce much "skin effect.") Notice that the path for electric current goes RIGHT THROUGH YOUR HAND.

Find one of those neon "Flicker-Flame(tm)" or a Pink Flamingo Bulb with the green phosphor palm tree. Also buy a white ceramic light bulb socket to fit the bulb. Screw in the bulb, then touch the white HV wire to either of the socket connections. It glows, and also will repond to your fingers. KEEP FINGERS FAR FROM THE METAL BULB BASE, or perhaps wind many layers of vinyl insulation tape along the edge of the bulb base to prevent direct contact by fingers.

Bend the HV wire and the bare ground wire so the tips are about 1/8-in apart. Turn on the device, then push the wires together briefly. PLASMA ARC FORMS!!! Little violet spark. It's terrifically hot, and heats the wires to dangerous temp. (Runs the batt. down quickly too!) Carefully use the arc to cut things. You can slice through plastic bag, or thin solder, or through very fine magnet wire. Melt tines off a plastic fork. It sets paper on fire! Perform "Electric Discharge Machining" on a pickel or various fruits. Electrosurgery on lunch meat. Try sculpting some beer foam.

Sandwich a piece of alum. foil (or copper PCB) between two 1/16" sheets of plexiglas or styrene. Wire the foil to the HV terminal, and for safety, cover all the edge-slots with RTV silicone caulk or epoxy. (Optional: connect the ground wire to actual ground, or to a few feet of scrap wire.) Power it up. Any neon or fluroescent tubes placed on the insulated plate will respond to the high-volt e-field and light up. The plastic keeps you from getting zapped-burned accidentally. Actually this is identical to the power supply for a "Plasma Mug"

For this one you need a variable DC power supply and a fluorescent tube. (Perhaps try using a cheap 6V wall transformer hooked to a lamp dimmer?) First connect the Tesla Coil HV terminal to one pin on one end of the fluorescent tube. Tape a thin (1/8") strip of metal foil along the length of the fluorescent tube, and attach the foil to the TC ground wire. Now vary the power supply between zero and +6V. A glowing "plasma finger" advances and retreats within the fluorescent tube. Vaguely resembles a Star Wars lightsabre. Uses actual plasma. (Note: a hundred of these can be computer-driven as a large electronic sculpture. See more hardware details.)

No! Bad! If you want to misuse Tesla technology, first go watch a small TC installation blowing up all the major cities in Europe. It's enough to make you go sit in a hotel room for the rest of your life, and stock up on pigeon feed.

  • High Voltage Hobbyists
    huge Teslacoils
  • Remember, it's not how large your Teslacoils are, it's what you do with them
  • Insecure high-volt experimenters always building larger Teslacoils.
  • Avoid Teslacoil envy, instead start small
  • It's NOT OK to touch your own teslacoils. You could get hurt that way. Even worse is to touch somebody else's, when you don't know exactly how dangerous they are.
  • Umm... ummm... nope, can't come up with any others. Quickmeme? Stupid bumper-stickers for TC fanatics?

Bumbershoot Seattle, 2005

EVEN HIGHER VOLTS: mod the CXA2090 for higher power

On these 5-volt devices, if you crank the input higher than around 6Vdc, the coil will become warm. If you go much above 8V, an internal arc will usually destroy it.

However, on the CXA2090 this problem can be cured. Inside the little white transformer, the ground-wire for the HV secondary coil runs across that coil. Perhaps this is an intentionally bad design to keep the HV below a certain voltage (where any accidental overload will trigger an arc and shut down the output.) To fix it, carefully slice the white tape along the sides of the xformer and remove the tape from the bottom side (circuit side, no components.) Go slowly, since the hair-thin ground wire runs across this tape. With the ground wire exposed, very carefully slather it with RTV silicone caulk or with epoxy. Don't break the wire!

Or, perhaps disconnect that wire so it no longer extends across the coil, then sandpaper the varnish from the end of the tiny wire and solder it to a different ground location. Put a bit of silicone goo on the thin wire to keep it from breaking accidentally. This will let your coil put out far more volts without destruction. (Still the coil gets quite hot though, so don't run it too long.)

This device is about as hazardous as a soldering iron. While this thing can't shock you, it can easily burn holes in your skin with its few-watts electric arc. In other words, don't "zap" yourself on the high-voltage section, or you'll end up with a tiny black-charred pin-hole in your finger, a cloud of burning-hair scent, and a small painful burn. Also it can damage medical implants, computers, phones, etc. See: "electrocautery"


Above, 100 tesla coils driving fluorescent tubes in Plasma Finger mode

"Plasma fingers" art device at Bumbershoot


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