Picture of How to build a Tesla Coil
This Instructable will walk you through building a medium sized Tesla coil.
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Step 1: DANGER

Picture of DANGER
Unlike some other high voltage experiments, a Tesla coil's streamers can be very harmful. If you are shocked by the streamers, you will not feel pain, but your circulatory and nervous system can sustain severe damage. DO NOT TOUCH IT WHILE ON UNDER ANY CIRCUMSTANCES.

Also, I don't take any responsibility for you hurting yourself.

This isn't to say that you shouldn't get into high voltage though, its just that if you are planning for this to be your first HV project, its a little to involved. Instead, try out a nice microwave oven transformer, and be safe!

Step 2: Gather the Materials

Picture of Gather the Materials
The total cost came to around $25, being that I already had the wood, Snapple bottles, PVC, and glue.

Secondary Coil:
  • A length of 1.5" PVC (the longer the better)
  • About 300 feet of 24 AWG copper enameled wire
  • 1.5" PVC screw-thing (see picture)
  • 1.5" metal floor flange with threads
  • Spray on enamel
  • Circular, smooth metallic object for the discharge terminal
Base and Supra-base
  • Various pieces of wood
  • Long bolts, nuts, and washers
Primary Coil:
  • About 10 feet of thin copper tubing
  • 6 Glass bottles (Snapple bottles work really well)
  • Table Salt
  • Oil (I used canola. Mineral oil (horse laxative) it preferable as it doesn't mold, but I didn't have any.)
  • Lots of aluminum foil
And a HV power source such as a NST, OBIT, or other transformer that gives off at least 9 kV at around 30 mA.
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Glenn7815 years ago
 for the love of god do not use 6 snapple  jars with a 15kv 30ma nst you will get about 10 min of run time out b4 1 or more blow!!! all 6 were leaking badly. i think ill try a serise/parallel with 12 of them
HaykD Glenn7812 days ago

Why do they leak? Isn't there any way to prevent leakage. Or how you know that caps are leaking?

how many volts will one of the snapple bottles produce?
lol!!! good thing you did cause I have 4 litle girls in my house, is it ok if i use 9 small mouth pint jars instead?

(i only would have done 3)

thanks alot for makeing these instructions.

ps i couldn' comment on the right one so this is for DevCoder
DevCoder (author)  electridanger4 years ago
DevCoder (author)  Glenn7815 years ago

I just fixed the Instructable!
EdS36 days ago

Finished my secondary winding, does the bottom of the secondary winding wire connect to anything or should I just cut it off flush to my pvc?

EdS31 month ago

Does the winding direction matter?

Cuanto tiene que medir el tubo de pvc y el de cobre

Also, what wire is used for connecting the NST, capacitors, spark gap, ect...

Also, how can I ground the primary and the secondary coil if they can't be grounded in the same area?

what is the "1.5" PVC screw-thing" used for?

ZariusI1 month ago

You should try to update your directions cause they are hard to understand and how long should are bolts, washers, nuts, wood and PVC pipe should be. Also what is a circular, smooth metallic object for the discharge terminal is what did you use ..maybe a metal bowl. But anyway thanks for making this and tell us were to go for the next Tesla Coil.

EdS33 months ago

Is there an alternative to using Snapple for the capacitor.

EdS33 months ago

Will this work for the secondary coil?

science mad3 months ago
i want to made this i dont have 9kv trans for mer
Luis963 months ago

Can someone please clarify me on this aspect of Tesla Coils: when building one, do we have to calculate anything, like how many windings, or the capacitor's capacitance, or can we just move on without doing any math?

Thank you!

you shouldn't have to calculate the windings, but you might want to find the capacitors capacitance.

How much oil did you use and what kind of wire is that?

I'm doing this for my science fair so I would very much appreciate a quick response please.

CCube557 months ago
how many for a 3 kv nst? (snaple LEYDEN Jars) And what would happen if I did not have 6 jars...?
azvampyre7 months ago

Do we need a live cat, or can I scrape one off the road. The instructions werent clear on that point.

ChadC18 months ago

What does that cat have to do with a Tesla Coil?

Jknapp252 years ago
It looks like your capacitors are in series, why aren't they in parallel? Also deep should the wire go into the bottle? Does it even matter because the salt water mix is considered the inner plate, the salt is all at the bottom though. Lastly, if the foil is the outer plate, how do you connect a wire to it?

they prevent the coil from short circuiting... :)

current limiting capacitors, not smoothing
stevo-d4 years ago
Ummm, harmful amounts of UV light appears to be visible at your spark gap... I'm no expert here, but from what I've read, you really should have that enclosed for the safety of your eyes... Has been described elsewhere as like watching an arc welder, and use arc welding eye protection if you DO NEED to look at it for any reason.

I would care more about the radiation ;) but youre right, the UV light isnt very healthy for your eyes :P

LaserByte stevo-d10 months ago

does this just mean to wear sunglasses during use? If so, I am fine with that.

the current is only ~20mA, essentially the amount of power to drive an led
Your probabally going to get hurt anyway, so it doesent matter. I highly doubt that it is as bright as an arc welder, and will harm your eyes that much
Well you're right that it would not be as bad as an arc welder because if it was, it would probably melt the terminals!
My point is however that high voltage arcs do indeed produce harmful ultra violet light and just letting anyone intending to do this know to take caution.
As for "getting hurt anyway", I will disagree... Again, we should take caution... Make some pretty sparks, but DON'T make yourself part of the circuit!!!
Yeh i agree, dont be a conducter of that circuit, it will mess u up. Now that i look at the bottom, where the spark gap is, it looks kinda bright, take caution
so what would happen if i used a semi-silvered mirror to protect the spark gap, but still let u see the spark?
Semi-silvered mirror might work, but a few filters to filter out most of the light would work just as well. Rosco has UV filters you can buy, as well as good filters you could use to filter out most of the visible spectrum. That way you'd be able to see the spark but wouldn't have to worry about the intense light.
I wouldent bother...
I'm not an expert in light radiation, but I would bet you would still get UV reflecting off such a mirror.
I used to work with high intensity UV light equipment for curing acrylics and we needed to be able to watch it... We worked with the work-piece and light source behind a thick (5-8mm) piece of orange transparent perspex - you could still see the light shining, but it no longer appeared blue and no UV would get through.

I would also like to mention that the equipment I worked with was an arc lamp that sent the UV through an optic-fibre cable - the light coming from the end of the cable would easily set tissue paper on fire, and a few careless co-workers got some nasty burns.

adamnsmith3 years ago
i wonder if you could make a mini hand held tesla coil with a few 9 volt batterys

I would use some 18650 cells, 1x 9V-Block has about 300mAh and 9V, 2x 18650 have 9V and 3Ah (at the same size, maybe a little bit bigger), ten time more use time ;)

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