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HF Tesla coil and it dosn't hurt?

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Alan

Wed Oct 17 2007, 08:05PM

Registered Member #1069 Joined: Wed Oct 17 2007, 06:23PM
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I've done my research over several years and found much conflicting info.

I want to know if it is possible (for one to, not for me to) build a large Tesla coil or similar device that can get a bolt of plasma\lightning to jump a significant gap (maybe 50cm or more), land on a person and for the person not to be hurt. Is there something called the skin effect that allows this to happen with HF AC?

...

Wed Oct 17 2007, 10:18PM

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

Well, you can't 'feel' high frequency, except for the heating it causes. If you were to use a SSTC running at a suitably high frequency and using very short bursts to limit the amount of skin that is vaporised with each spark, it would be possible.

I still wouldn't build it, mainly because all of the power has a tendency to flow through parts of you body that you would rather not have large amounts of power flowing through (veins are supposed to carry the bulk of the current IIRC), not to mention what it would do to people with pacemakers/etc.

Hazmatt_(The Underdog)

Wed Oct 17 2007, 10:45PM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
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Posts: 1735

If anyone attempted to do this they would suffer very large amounts of nerve damage along the parts exposed to the HV. You can't feel pain from the high frequency current because the nerve ending isn't fast enough to respond to the frequency of the potential (someone else will probably state that in a better way then I can at this time).

Anyway, not a good idea in general. A Faraday Cage would be a wise investment.

ragnar

Thu Oct 18 2007, 12:45AM

Registered Member #63 Joined: Thu Feb 09 2006, 06:18AM
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Posts: 1425

Alan wrote ...

I've done my research over several years and found much conflicting info.

You're right that, unfortunately, there is little between material that explicitly states you *must not* expose yourself to arcs, and material that states "it's OK because..." -- hopefully we can clear that up in this thread.

wrote ...
...get a bolt of plasma\lightning to jump a significant gap (maybe 50cm or more), land on a person and for the person not to be hurt.

Contact with plasma/lightning will cause burns. This is plain and simple:

You mighn't feel physical 'pain' result immediately, but the loss of sensitivity will scare you later. Even more scary is the potential for deep tissue burns. Just imagine a blood blister forming some place where you can't extract it through your epidermis. =P

I presume you've seen plenty of videos of people holding their hands up to tesla coils, and noticed the bright yellow flashes seen where the arc contacts skin. You will guess correctly that those yellow flashes are nothing other than burning flesh.

wrote ...
Is there something called the skin effect that allows this to happen with HF AC?

This is an often-quoted (and widely misunderstood) 'excuse' for touching arcs.

Whilst you may be lucky to "spread" currents by conducting arcs to a metal target with a larger contact area on your skin, I don't think anyone here would advise it.

The truth is, you really have no way of knowing where the juice is flowing; but if there are arcs in the first place, it had to go somewhere.

If you want to draw arcs from a coil, it's recommended (see better sites like Steve Ward's) to use an insulator as a stick, with a groundwire running up to a metal target on the end; that way you as the demonstrator are not connected to ground OR high-voltage.

Nik

Thu Oct 18 2007, 01:15AM

Registered Member #53 Joined: Thu Feb 09 2006, 04:31AM
Location: Ontario, Canada
Posts: 638

One thing that hasn't been mentioned here but is mentioned quite a bit at work has to do with your blood. It is possible for electricity flowing though you to cause a little bit of your blood to be burned and clot. In extreme cases the clot grows and you can lose fingers or even limbs. Any electrician who takes a shock of >250v gets put into observation for 24 hours to make sure this doesn't happen.

Moral of the story: Don't touch electricity

Simon

Thu Oct 18 2007, 01:28AM

Registered Member #32 Joined: Sat Feb 04 2006, 08:58AM
Location: Australia
Posts: 549

Matt's said it pretty well.

wrote ...

I want to know if it is possible (for one to, not for me to) build a large Tesla coil or similar device that can get a bolt of plasma\lightning to jump a significant gap (maybe 50cm or more), land on a person and for the person not to be hurt.

The trouble with this question is ambiguity. Do you mean "get hurt" as in "feel pain" or as in "receive bodily damage". Remember that ambiguity when you read pages on the web. Also remember that some authors aren't even aware there is a difference.

A nasty thing about electrical burns is that, while they might look just like a pinprick on the surface, they can penetrate deep through the skin, depending on the flow electricity.

Alan

Thu Oct 18 2007, 04:17PM

Registered Member #1069 Joined: Wed Oct 17 2007, 06:23PM
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Thank you for your useful and wise replays.

Tom540

Thu Oct 18 2007, 04:33PM

Banned on 3/17/2009.
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Wow, a blood clot that is a scary thought especially doing it without pain. Although I'm wondering a TC output doesn't carry much current and your body is kinda like a giant mega Ohm resistor so how much clotting can there actually be. Instead of trying to figure out I just look at it like, It's better to be safe than sorry. I need my fingers and limbs.

Kizmo

Thu Oct 18 2007, 07:32PM

Registered Member #599 Joined: Thu Mar 22 2007, 07:40PM
Location: Northern Finland, Rovaniemi
Posts: 624

Is TC output from toroid really AC? or HF pulsed DC?

..does it make difference?

Zum Beispiel

Thu Oct 18 2007, 07:59PM

Registered Member #514 Joined: Sun Feb 11 2007, 12:27AM
Location: Somewhere in Pirkanmaa, Finland
Posts: 295

Kizmo wrote ...

Is TC output from toroid really AC? or HF pulsed DC?

It is AC. The tank circuit is a HF LC oscillator (or if it's a SSTC the inverter does that) and the secondary coil amplifies those oscillations to a higher voltage.

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