Question

guys watch this quick vids:
http://www.youtube.com/watch?v=CdF3cLbzWUc

The description say tat it is 300kV, but the one who holding spanner didn't get any shock damage how come?

Answer 1

What really matters isn't the voltage but the total charge transfer per second; i.e., the current.

That being said, this is not a smart thing to do.

If you're interested in the physics of this, watch this lecture:
http://ocw.mit.edu/courses/physics/8-02-electricity-and-magnetism-spring-2002/video-lectures/lecture-6-high-voltage-breakdown-and-lightning/

(He does a similar van der Graaf experiment beginning at 40:30.)

Answer 2

This is actually a Tesla coil, and what he shows is the skin effect. It's a bit too technical to explain it properly here, but the main point is that the current only flows on the "skin" of an object. So all the charge is moving on the surface of the spanner, and also on his actual skin. Since it doesn't even touch the nerves under the surface of the skin he doesn't feel anything.

Same effect is exploited for long range transmission of electric power.

Answer 3

also note, this is not a a harmless thing to do, so don't do it :D

Answer 4

Ah, it is a Tesla coil. Thanks.

Glad we agree however that this is not a smart thing to do! ;-)

Answer 5

Yes yes, you can see a lot of people doing stuff like that on youtube, gotta be careful these days :D

Answer 6

gogind, you give very good answers. I'm glad you're around.

Answer 7

Ah, thank you! I'm glad to help, I'm just surprised that not many people are using this site.

Answer 8

We need more, and more knowledgable people to help field answers. The mathematics group has a gravitational pull that makes it harder for this group to get critical mass, but hopefully we'll get there.

Answer 9

hehe i will not try to do sumthing like that, just curious ^^