Here is a story of someone dieing from high voltage/low amperage.
http://www.cnn.com/2007/WORLD/americas/1......dex.html
Here is another...
http://www.msnbc.msn.com/id/6955223/
and another...
http://www.cbsnews.com/video/watch/?id=701569n
and another...
http://www.upi.com/Top_News/2009/04/21/P......0336981/
and another...
http://www.nypost.com/seven/02252009/new......6896.htm
and another...
http://www.nytimes.com/1994/11/25/us/a-b......ath.html

I think I made my point!

Not to mention...

I held my finger to my Tesla coil to see how long I could stand it and it burnt a hole all the way to the bone.
You put that over your heart, it can easily kill you.

Randi

So, Randi, what, exactly, are you trying to say?

(by the by, I love commas)

I was removing a capacitor from a cheap compact camera that used just 2 aa bateries. Well I got zapped big time as it was holding a charge. I friend said it could have killed me. Is this possible?

From 2 AA bateries? LOL

That's exactly what I thought. Just 2 AA bateries could not hurt you. I am not sure how much of a charge the capacitor held but it definately gave me a jolt! lol
I am trying to build a very small unit similar to Fism Flash but very compact. Any ideas here?

I have Fism and love it, but need something at least half that size for an effect I am working on. Any help or ideas I can get would be great.

Try the IBM convention. It's a lot smaller than FISM.

Or try the SAM convention. It's even smaller.

It's my understanding that what kills you when you get an electric shock is not necessarily the voltage or the amperage per se. It's the power deposition in the tissues that does you in. Whether it depolarizes the heart muscle or cooks the tissue, death is form power deposited. Power= amperage squared X resistance. Sinced the resistance is a relative constant for the human body, the power is proportional to the amperage. But, using a very high amperage and low voltage with low resistance will deposit little power.

Or in other words,

Twinkle Twinkle little star, power equal I squared R

Power also equals volts times amps. But both of these are DC equations.

For AC PF = cos(theta) and (theta)φ = power factor angle
(phase angle) between voltage and amperage.

PF is the power factor.

Voltage does NOT harm you...VOLT-AMPs do. This is amperage multiplied by voltage. High volts will not even tickle you if the amperage is low enough.

Like most electrical apparatuses a tesla coil needs to be properly calibrated/tuned. When done, the current will flow over the surface of your skin, and not penetrate to muscles, or nerves, and so do no harm. Improperly tuned coils can fry you.

The way that Electronics is taught (at least in the U.S.) leaves many students in the dark as to exactly how it works. What we are talking about is the difference in electron “potential” (or in most respects, the quantity of electrons) between two (or more) bodies. When electricity “flows” those electrons are moving from a region of high potential (negative) to a region of lower potential (comparatively positive). If enough of those electrons pass through you, it can cause damage.

The voltage vs current argument really doesn’t apply. Imagine being buried under a ton of BBs, versus being shot by a million tiny flying BBs. Neither scenario sounds particularly attractive right?

But what happens at higher frequencies is the electrons themselves begin to behave differently. The “skin effect” is caused by a hysteresis of the magnetic field associated with alternating current, pushing the electrons outwards so that, at very high frequencies, all the “activity” seems to occur outside the conductor, with very little electron movement within.

If your body is to be part of the circuit, you want VERY high frequency, as this will keep most of your internal organs out of the electron path. It’s still not a toy, and should be attempted only (in my opinion) if you can apprentice with someone who’s been doing it for a while. At the very least, contact the Physics Department of your local University.

A lot of misinformation here. One thing I will address and that is frequency can also prove deadly. If you are bit by 120V at 60Hz regardless of the amperage, and the path of that current crosses the heart it can cause a heart attack with or without a pacemaker. As far as intentionally grounding yourself to receive a jolt for amusement, it is also not a good idea. Electricity cooks you from the inside out, not the other way around.

I like the idea of using the skin effect, but I agree that it's a dangerous hobby. As said before, it's the total power (instantaneous power x time) delivered to the internal organs that will kill you. Not V or A. Randi, in the examples you gave the tasers have high voltage, but also delivered enough amps for enough time to kill.

What a lot of people here don't seem to realize is that the amperage is rarely a constant. So you can't speak of something (a taser, a tesla coil) delivering a certain amount of amps. This depends (in the DC case) on the resistance across which the voltage from the device is applied. Most devices have a fixed voltage and will therefore have a varying current output. With these devices the current is inversely proportional to the resistance (I=V/R), up to the point where the product of voltage and current reaches the maximum power that the device can deliver. If the resistance is lowered even further, the voltage will drop. So:
- The 110V from the wall can kill you because it can generate a moderately strong current, but it can do so for a long time because of the power behind it (which, for all practical purposes, is limited only by fuses and surge protectors).
- A low voltage can never kill, because with the normal resistance of the human body it will not be able to generate a high enough current and therefore deliver enough power.
- A (small) Tesla coil does not kill. It can build up a very high voltage (> 10'000 V), and therefore has the potential to create a large current in the human body. But the total charge built up in the coil is small, so when you touch it, at least for small coils, this voltage will almost immediately drop to zero. The time that the large current flows through the body is so short that nothing happens. When the coil is larger of course, it can contain more charge and the current can flow longer, making it more dangerous.
- Tasers usually do not kill, because the time the (high) voltage is applied is very short. However to do what they're designed to do, they must necessarily work in the danger zone. A taser that people don't feel is useless. That's why in a small number of cases where several risk factors, such as a skinny person with a (undiagnosed) heart condition, thin clothes, manufacturing problems with taser etc. coincide, it can go wrong.

Tell me about it! One thing most posts should change is add "usually" to "can't" and "won't". Electricity is a subject that gets more mysterious the more you know about it. Just a small interrupt in the delicate circuit of the body can have unpredictable results. Electricity does not have to "fry" your body to kill you. Once the heart stops...

Jim
WC8M

Volts devided by resistance gives amps. Volts times amps gives power. High power will kill. volts and amps are related. lower one raises the other since energy can neither be created nor destroyed only changed. for example 110 volts at 10 amps gives 1100 watts of power, raise the volts to 220 and the amps go down to 5 but 22o times 5 is still 1100 watts of power. as energy can not be created or destroyed. and as for wanting high frequency High frequency electricity will give nasty burns, Ask any ham radio operator. The FCC has strict rules about such things. Why does the FCC get involved? because high frequency ac in the 3o to 300 kilohertz range and higher are radio waves.

point being unless you have a thorough understanding of what you are doing I think it is best to proceed with great caution. Just my opinion.


mightydog
David

http://www.youtube.com/watch?v=PdrqdW4Miao

Notice the special suit he wears to protect himself. Including his head.

mightydog
David

http://www.youtube.com/watch?v=wYwFWMxdiSM&feature=related

http://www.youtube.com/watch?v=SRcleKi5kyo&feature=related

http://www.youtube.com/watch?v=vRJnEw5HEbY&NR=1

http://www.youtube.com/watch?v=dCAMX41ZKfE&feature=related

mightydog
David

Agreed that it was impressive to see an older Thin White Duke appearing in full dress stepping out in front of a wall of light, almost exactly the choreography from his 1976 onstage entrance.



Usually these are discharge devices which produce high voltage and very low current. There is a long history of their use in carnivals over the last century or so.

BTW, the electrical breakdown of air is about 33000v/cm or 100,000V/inch. so a foot long spark in air requires a significant voltage buildup - about a million volts.

The Tesla devices are high frequency sources of high voltage - and I strongly suggest you learn enough about such devices in a safe environment before exploring their use at home or in amusements.

Kindly do not confuse what appears on a movie screen, especially in a big budget production with what the full apparatus and technology needed looks like in operation. There are photos of the Tesla devices which inspired that movie in use and some fairly detailed discussion of their construction. Tesla is a sort of cult hero so a few minutes searching via Google should get you from pictures to plans.

Have fun - but with an additional focus on safety,

Jon

Sorry to necro a thread that has been dead for a while.
Yes, the device was called a Tesla coil. Tesla showed that high frequency high voltage could pass along the outside of the body, using the "skin effect."
I've built and played with Tesla coils for years. And yes, they can be VERY dangerous. The primary voltages in some of my Tesla coils are around 15,000 volts (15 kV) and AMPS of current. It is LETHAL. But the secondary can pass through your body. The spark can still BURN you. That's why folks use metal thimbles to potect the fingertips to arc to a key or metal rod.

But recently, just a few years ago, a company came out with an afforable small coil to play with. The cool thing is, the coil is solid state (a little safer) and you can play MUSIC through the arc!

Check these folks out at: http://onetesla.com/