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Thinking of building Tesla Coil

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adamjon858

Tue Mar 18 2008, 03:22PM

Registered Member #1401 Joined: Tue Mar 18 2008, 03:20PM
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Posts: 12

Hey,
I'm thinking of building a Tesla Coil for a project at my school. How dangerous are these? I was looking at 12kv transformers on eBay and was concerned about the potential health hazards.

flannelhead

Tue Mar 18 2008, 03:37PM

Registered Member #952 Joined: Mon Aug 13 2007, 11:07AM
Location: Finland
Posts: 388

It depends on the output power how dangerous is it. Those 12kV transformers are likely neon sign transformers and it depends on the amperage is it dangerous or not. The transformer itself can shock you kinda badly or possibly kill you.

I don't know how experienced you are with electronics, but I could recommend you building a solid state coil (SSTC). In SSTCs those high voltage transformers aren't needed, and the power can be quite low (I ran mine@7W) Look at Steve Ward's Micro schematic for example:

This can give you some nice results even driven with 12-24V, and it won't be dangerous. The worst thing it can do is give you a nasty RF burn but no more. Look at other people's results:

If (and when) you have more questions feel free to ask!

adamjon858

Tue Mar 18 2008, 06:24PM

Registered Member #1401 Joined: Tue Mar 18 2008, 03:20PM
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Posts: 12

I'm looking to build one with at least an 8inch spark. From what I've seen of Tesla coils, you can pass your hand through them harmessly. What would the RF burn be from (I'm guessing RF refers to radio frequency).

And the amperage on the transformers I was looking at was around 50mA

...

Wed Mar 19 2008, 12:33AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

The streamers from any tesla coil are extremely hot, and will burn you regardless how small the coil is. Lucky you have a nice layer of dead skin that is vaporised before you do too much damage, so you can usually get away with touching the output of a coil for short periods of time without too many ill effects. Unfortunately you are also passing large amounts of current through your body as you do this, which can cause internal problems (there haven't really been a whole lot of studies done on this, so we don't really know how much damage is done).

I would also recommend building a SSTC, as they are in general considerably safer and more controlled than a SGTC. Touching the output of a sstc putting out 8" of streamers is only borderline insane, 8" of STGC streamers is going to hurt quite a bit.

adamjon858

Wed Mar 19 2008, 02:39AM

Registered Member #1401 Joined: Tue Mar 18 2008, 03:20PM
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Posts: 12

Can you guys give me a list of what I need to buy in order to do this(SSTC) ? Along with perhaps a price range...

Arcstarter

Wed Mar 19 2008, 02:47AM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

Well for a solid state tesla coil if you make Steve Wards class e you can probably get away with spending less that 100 bucks.

EDY19

Wed Mar 19 2008, 03:37AM

Registered Member #105 Joined: Thu Feb 09 2006, 08:54PM
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Posts: 408

There are lots of different designs and topologies for solid state coils, I would look around a Steve Wards website, and decide on one that fits your needs. A half bridge coil would be a good starting point, and a self resonant design such as one using a 74HC14 is a pretty easy choice circuitry wise, and is not difficult to get up and running.

teslacoolguy

Wed Mar 19 2008, 04:00AM

Registered Member #1107 Joined: Thu Nov 08 2007, 10:09PM
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Posts: 792

Build Steve Wards class E coil for several reasons. 1st i built it ad had up and running excluding the secondary in under 2 hrs. yours will probably take longer but take your time and be sure to wire things right and everything should work out good. 2nd it is a very low power and i have touched the output multiple times with just a mild pinprick feeling on low duty cycle and pulse rate but if you crank the duty cycle up the discharge will become near silent and is very hot and you will get a nasty rf burn but other than that it is a very safe coil to build for a beginner.

adamjon858

Thu Mar 20 2008, 04:02AM

Registered Member #1401 Joined: Tue Mar 18 2008, 03:20PM
Location:
Posts: 12

How big a spark can you get off a class E coil?

Is this the schematic?

Alright so I'm going to make a parts list:
-bunch of resistors (I've got a lot of 1/4W carbon ones...will those work?)
-555 timer
-LM7812 IC
-UCC37322 (some kind of gate,amp, or transformer?)
-IRFP460A (no frikin clue what this is)
-1N34A diodes
-.1uf, .33uf, 4.7uf, 330uf, 2200uf capacitors
-25V AC power supply (can someone find me a good one on ebay plz?)
-Tank Capacitor (what is this?)
-Antenna (is this just a normal antenna?)
-Primary and secondary coils (whats a good diameter/height?)

flannelhead

Thu Mar 20 2008, 11:51AM

Registered Member #952 Joined: Mon Aug 13 2007, 11:07AM
Location: Finland
Posts: 388

1/4W carbon resistors will work just fine...

The UCC is a MOSFET/IGBT gate driver, so yes, it's an amp.

IRFP460(A) is a MOSFET

Tank capacitor is for tuning the switching circuit in perfect resonance. You will need a bunch of small (220pF) caps. Use polypropylene, as said in the schematic.

Antenna is a piece of wire (10-20cm)

Primary and secondary: to be sure, use just about the same values Steve used. When you are more experienced, you can try different sizes.

Oh, and by the way, Google and HvWiki are both your friends.

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