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Topic: High Frequency Electicity
Message: Posted by: Xaethia (Apr 2, 2009 10:44PM)
Hello,

A couple weeks ago I was looking in Ripley's Believe It or Not. There was a little article and a picture of someone using a machine that electicity was coming out and it wasn't harming her/him (can't remember).

I tried to do a little research and as far as I got was I THINK (!!!) it was a machine invented by Telsa - for he experimented with hiqh-frequency electricity. It also said that high-frequency electricity doesn't harm our skin.

In The Prestige (the film) the machine that makes the main character clone him uses high-frequency electricity (my guess, for it does not harm the him).



What is this machine called?
Has anyone got any idea how much a machine like this would cost? (I am guessing quite a bit)
Why doesn't high-frequency electricity harm our skin?

Xaethia
Message: Posted by: Father Photius (Apr 2, 2009 10:57PM)
Frequency is rate of cycle in AC. It isn't voltage or frequency that kills you it is amperage or current. Tesla's coil generated a high frequency, high voltage, very low current AC. Basically his coil is a resonant transformer. They can be obtained from various sources for modest amounts, but until you learn a LOT more about electricity than you show above, I would highly recommend you not use one.
Message: Posted by: randirain (Apr 3, 2009 12:04AM)
Well... actually... High voltage with low amperage can kill you. Just like low voltage and high amperage. They are two sides of the same coin.
But for the most part... father is exactly right.

I own a Tesla coil that I built myself. I use it in an electric chair act that I perform with in our show the Dead Girl Circus. http://www.deadgirlcircus.com

And if you think it doesn't hurt... well you would be very wrong!
I have people touch me with a grounded rod while the voltage passes through me.
It hurts and leaves burn marks on me.
I once had the voltage go through my head.
That didn't feel good at all. My depression went away and I probably lost some memory, but I won't notice that.

Any way...
there is plenty of information on Tesla Coils on the internet.
They are pretty easy to build, but the parts, especially the capacitors, can be hard to find.

Randi
Message: Posted by: Xaethia (Apr 3, 2009 06:56AM)
Cool.
Thanks
Message: Posted by: lin (Apr 3, 2009 04:59PM)
How about a Wimshurst spark generator? The capacitors are leyden jars you make yourself.


http://en.wikipedia.org/wiki/Wimshurst_machine


http://makezine.com/17/wimshurst/

http://www.makershed.com/ProductDetails.asp?ProductCode=9780596155605


http://www.instructables.com/id/Wimshurst-electrostatic-generator/
Message: Posted by: randirain (Apr 3, 2009 10:44PM)
Very interesting... thanks for the post.

Randi
Message: Posted by: lin (Apr 4, 2009 04:01PM)
My pleasure.

cheers
Message: Posted by: John Long (Apr 8, 2009 06:21PM)
[quote]
On 2009-04-03 01:04, randirain wrote:
Well... actually... High voltage with low amperage can kill you. Just like low voltage and high amperage. They are two sides of the same coin.

[/quote]

I'm not sure what you are thinking of - when you get a static shock, you are experiencing a very high voltage/low amperage flow of electricity. Other than the surprise and "snap", it is harmless. I don't remember the break-down voltage for dry air, but I fairly sure it is over 1000 volts. Yet, there is a point where the amperage may not be low enough.

John
Message: Posted by: randirain (Apr 8, 2009 06:53PM)
[quote]
On 2009-04-08 19:21, John Long wrote:

I'm not sure what you are thinking of...... Yet, there is a point where the amperage may not be low enough.

John
[/quote]
You answered your own quetion.
I was just stating that just because the amperage is low doesn't mean that any amount of voltage can't kill you.

If you have a wide river flowing very slowly into a lake...
And you have a narrow river flowing very rapidly into a lake...
They both dump the same amount of water into the lake at any given time.
Two sides of the same coin.

Randi
Message: Posted by: Max Krause (Apr 11, 2009 05:03PM)
Voltage will not kill you amperage will. It's the amount of amperage that can cause your heart to stop not the voltage. That's why people with pacemakers have to be so careful around electric current.

It is rare that anyone dies from a stun gun or taser however, there is enough amperage even there in some instances to kill you.

I don't recommend you test this to find out. There is a HUGE difference between amperage and voltage and one definitely kills. The other does not. It always takes the current (amperage) to do the killing. It's like sticking your tongue on a 9 volt battery. There is so minimal amperage that all it does is cause mild discomfort. However attach your tongue to a 12V car battery and you see a NOTICABLE difference if you are still alive to talk about it.

And that's the electricity lesson for today class.


Amperage = Death

Max
Message: Posted by: randirain (Apr 11, 2009 07:34PM)
[quote]
On 2009-04-11 18:03, sleightofhand1971 wrote:
Voltage will not kill you amperage will. It's the amount of amperage that can cause your heart to stop not the voltage. That's why people with pacemakers have to be so careful around electric current.

Amperage = Death
[/quote]
And you would be wrong.
If voltage can't kill you, there would be no danger signs that say DANGER HIGH VOLTAGE.
It's all about ohm's law.
This article says exactly what I have been saying.
http://www.allaboutcircuits.com/vol_1/chpt_3/4.html

And that's the REAL lesson for today.

Randi
Message: Posted by: Max Krause (Apr 11, 2009 07:41PM)
Randi this is from your article. I studied electronics. DANGER HIGH VOLTAGE comes with high current (amperage) Which is what kills you..THE CURRENT

Harm to the body is a function of the amount of shock current. (AMPERAGE) Higher voltage allows for the production of higher, more dangerous currents. (AMPERAGE) Resistance opposes current, making high resistance a good protective measure against shock.


Helps to understand what you read.

Max
Message: Posted by: electric.ceu (Apr 11, 2009 09:19PM)
Electromotive Force(measured in volts) is the force that causes the electrons to flow through the circuit. The higher the voltage, the more electrons that are flowing. The more electrons flowing, the higher the current. The amount of current flow (measured in amperes) is directly proportional to the amount of voltage. It's like water pressure and gallons per minute in a water system. The higher the water pressure, the more gallons per minute. It takes about 100 to 200 milliamps of current flow to cause your heart to go into fibrillation.

[quote]
On 2009-04-03 01:04, randirain wrote:
I own a Tesla coil that I built myself. I use it in an electric chair act that I perform with in our show the Dead Girl Circus. http://www.deadgirlcircus.com

[/quote]

I'd like to see that. Do you have a video? Did you know that the electric chair came about because of the war of the currents? Edison and his people went to great lengths to discredit Tesla and Alternating Current. They used to publically electricute animals to show the dangers of AC. Of course Edison wanted everybody to use DC electricity.
Message: Posted by: randirain (Apr 11, 2009 09:56PM)
[quote]
On 2009-04-11 20:41, sleightofhand1971 wrote:
Randi this is from your article. I studied electronics. DANGER HIGH VOLTAGE comes with high current (amperage) Which is what kills you..THE CURRENT

Harm to the body is a function of the amount of shock current. (AMPERAGE) Higher voltage allows for the production of higher, more dangerous currents. (AMPERAGE) Resistance opposes current, making high resistance a good protective measure against shock.


Helps to understand what you read.

Max
[/quote]
It also says...
The amount of current through a body is equal to the amount of voltage applied between two points on that body, divided by the electrical resistance offered by the body between those two points.
It helps not to just repeat what you have heard and actually know what you are talking about.
I studied electronics too! And I come from a family of elctronic engineers.
The fact that you say that voltage can't kill you, shows you do not know all the facts.
Voltage can kill you... most definately.
To think that you can raise the voltage as much as you want as long as the amperage is low, and it won't hurt you is.. Wrong!

Like I have been saying... voltage and amperage are two sides of the same coin.


And we did a show last night where I did the elctric chair and it was filmed.
So I will have some footage soon.
Message: Posted by: Enzo (Apr 16, 2009 11:18AM)
To confuse things even more: Actually it's the amount of power delivered (which is the product of voltage and amperage) that does the damage. A very high static voltage, with no current (an 'open'; I=0) does not do any damage (c.f. Van de Graaff generator). Similarly, a high amperage without any voltage (a 'short'; V=0) doesn't "hurt" anything either (c.f. a perfect superconductor, which does not heat).

But in a practical sense Max is right in saying that it's the current flowing that ultimately does the damage to your body, because your body has a high resistance, so a power is generated if a current flows. But the only reason that current is the criterion is because we generally use voltage sources. If you'd use a current source, the voltage it is able to apply would be the criterion. And this depends on the amount of power available from the generator.

Often the voltage source is hooked up on the power net, which, if there is no weak fuse in between, can easily generate enough power to kill you.

Randi, I'd love to see the footage of your show, by the way!

(As we are throwing around credentials: I've a PhD in Electrical Engineering and work in medical research) (But I'm only an amateur magician ;))
Message: Posted by: Viano2 (Apr 20, 2009 03:06PM)
I too have a degree in Electrical Engineering. I have several Tesla Coils and an Electric Chair which I have performed many times. Enzo is correct in that it is power that destroys tissue. However that power is computed by multiplying current times resistance (of the tissue). But the voltage will determine how much current goes through the resistor, that's all. It has no other influence.

In order to be electrocuted, it is generally necessary to get this current in the vicinity of the heart. This generally does not happen with a Tesla coil because of what is commonly known as the skin effect. High frequency energy tends to flow on the surface of the resistor, rather than the core. This effect becomes more pronounced as the frequency increases. This makes Tesla coils less dangerous than they would seem to be. One would not normally "play" with a 60 cycle source of 15,000 volts. I can play with 15,000 volts because it is high frequency. On the other hand, if you have a 3 inch spark jump off your finger, there is a small patch of skin ( ie Surface) that is damaged and hurts like HELL. I wore a conductive glove when I did that bit. That spread the current flow over a less concentrated area and the resulting pain was negligible.

Viano
Message: Posted by: randirain (Apr 20, 2009 04:31PM)
Why do people keep repeating the same thing each one of us has said with just different words?

Father said...[i]
"Frequency is rate of cycle in AC. It isn't voltage or frequency that kills you it is amperage or current."[/i]

The I said...[i]
"Well... actually... High voltage with low amperage can kill you. Just like low voltage and high amperage. They are two sides of the same coin.
But for the most part... [b]father is exactly right.[/b]"[/i]

My whole point was that if have 100 billion volts at 10 milliamps, expect to die!
You can't increase the voltage to the nth level and expect it to stay safe as long as the amperage is low.

I said...[i]
"If you have a wide river flowing very slowly into a lake...
And you have a narrow river flowing very rapidly into a lake...
They both dump the same amount of water into the lake at any given time.
Two sides of the same coin."[/i]

Which is saying the same thing as, with out the talk of being hurt...[i]
"A very high static voltage, with no current (an 'open'; I=0) does not do any damage (c.f. Van de Graaff generator). Similarly, a high amperage without any voltage (a 'short'; V=0) doesn't "hurt" anything either (c.f. a perfect superconductor, which does not heat)."[/i]

Who is argueing with who here?
I never sid that amperage is not the part that damages you.
I just said that just because the amperage is low, doesn't mean electriciy can't kill you.
If you don't believe me, come to my home and I will hook my telsa coil up to either side of your heart and let's see what happens!
Which then goes on to...[i]
"In order to be electrocuted, it is generally necessary to get this current in the vicinity of the heart."[/i]

I have been trying and trying to stop argueing on forums like these, but people read what they want to read and just force you too.
I am so sick of this.
Read people!
We are all pretty much on the same boat here!

Randi
Message: Posted by: Outbreak Monkey (Apr 21, 2009 08:45PM)
Without getting drawn in to the argument I'd like to relate a story from one of the old-timer telephone techs here.

He made the good point that while everyone worries about the amps, you still need enough voltage to 'push' the current through your body

(Or as Randi Rain says)
[quote]
The amount of current through a body is equal to the amount of voltage applied between two points on that body, divided by the electrical resistance offered by the body between those two points.
[/quote]

Apparently there was a nice trick that the telephone technicians used to do with the apprentices..

They had massive battery cells that were quite low voltage, capable of delivering hundreds of amps for long periods (apparently they had warning labels on the sides stating such fact).

For a laugh, they'd chuck a small screwdriver or a spanner across the terminals, they'd glow - super hot, and sometimes even melt.

Then for a bigger laugh, they'd instruct the apprentice to pick up the batteries by the terminals (they always refused), so the old timers would demonstrate their super powers by doing it themselves. :)

The resistance of the metal was low enough that the current flowed quite happily between the terminals.
The resistance of the human body on the other hand was high enough that the current when flowing between the fingers was in the order of a few mA.

I'm sure a good time was had by all..

Cheers,
Monkey.
Message: Posted by: Enzo (Apr 23, 2009 09:33AM)
Good point, Viano. Didn't think about the skin effect.

[quote]If you don't believe me, come to my home and I will hook my telsa coil up to either side of your heart and let's see what happens! [/quote]
What will happen: a current much higher than 10mA, because, again, low currents won't kill you. Much you say is true, but I really must insist on this small point.

Given a person holding electrodes in a specific way and therefore having fixed body resistance, the current will increase with the applied voltage, and therefore higher voltage will mean higher current. The only mistake you keep making is in saying that "100 billion volts at 10 milliamps" will kill someone. This is simply [i]not true[/i]. Let's put aside the fact that the example you give is quite impossible to create (since the breakdown voltage of air is about 3 million volts per meter and therefore in your example the arms of the person holding the electrodes would have to be 33,000 kilometers (3/4 of the circumference of the earth) apart to prevent the current from passing through the air) and take more realistic "high" voltages in the order of MV. In this case it is perfectly possible to prevent harm by decreasing the current. You simply increase your body resistance, for instance by wearing isolating shoes, or standing on a platform with isolating feet (this only works of course if you only touch a single electrode and let the current flow to earth, rather than to a second electrode), or by limiting the total amount of available power, so the current will only flow for a very brief time (as in static shocks, or Van de Graaf demonstrations).

If you still don't believe me, here's a couple of excerpts from the
[url=http://en.wikipedia.org/wiki/High_voltage]WikiPedia page on high voltage[/url]:

"Voltages of greater than 50 V applied across dry unbroken human skin are capable of producing heart fibrillation [i]if they produce electric currents[/i] in body tissues which happen to pass through the chest area"

and

"Low-energy exposure to high voltage may be harmless, such as the spark produced in a dry climate when touching a doorknob after walking across a carpeted floor."

and

"Also, physics demonstration devices such as Van de Graaff generators and Wimshurst machines can produce voltages approaching one million volts, yet at worst they deliver a brief sting. These devices have a limited amount of stored energy, so the current produced is low and usually for a short time"

So, again, it's not the voltage, not the current, but the combination of (relatively) high current for a (relatively) long time that will kill you.

Best,
Enzo
Message: Posted by: randirain (Apr 23, 2009 12:41PM)
Well... You can't use wikipedia as any example. There is inaccurate information all over that place.

Let me tell you this...
I do not have a degree in electricty, but I do in nursing.
The heart works by electricity. In the heart is the AV nodes.
They put out an electric pulse, based on carbon dioxide in the blood, to make the muscle that is the heart pump.
If you put electricty over these nodes you can interupt the charging of the AV nodes.
You put my Tesla coil over your heart it can quite easily send you into A fib, or even worse V fib.
Oddly enough, another charge could start you back up.

So I will leave you with this example.
People have died from being electricuted with a stun gun.
It happened to a person in Dallas not too long ago who was stung by a police officer.
So that means it is possible to die from high voltage and low amperage.
And there is no argueing with that.

Randi
Message: Posted by: randirain (Apr 23, 2009 01:05PM)
Here is a story of someone dieing from high voltage/low amperage.
http://www.cnn.com/2007/WORLD/americas/11/15/taser.death/index.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/Police-sued-in-stun-gun-death/UPI-28681240336981/
and another...
http://www.nypost.com/seven/02252009/news/regionalnews/family_sues_nypd_police_over_stun_gun_de_156896.htm
and another...
http://www.nytimes.com/1994/11/25/us/a-baby-s-stun-gun-death.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
Message: Posted by: val and noid (May 16, 2009 11:43PM)
So, Randi, what, exactly, are you trying to say?
Message: Posted by: val and noid (May 16, 2009 11:44PM)
(by the by, I love commas)
Message: Posted by: ceme20 (May 27, 2009 03:08AM)
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?
Message: Posted by: Al Angello (May 29, 2009 10:37AM)
From 2 AA bateries? LOL
Message: Posted by: ceme20 (May 29, 2009 10:04PM)
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?
Message: Posted by: ceme20 (May 29, 2009 10:09PM)
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.
Message: Posted by: Bill Palmer (Jul 12, 2009 07:33PM)
[quote]
On 2009-05-29 23:09, ceme20 wrote:
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.
[/quote]

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

Or try the SAM convention. It's even smaller.
Message: Posted by: Larry Barnowsky (Jul 12, 2009 08:08PM)
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
Message: Posted by: Bill Palmer (Jul 13, 2009 07:52PM)
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.
Message: Posted by: Ejay (Apr 4, 2010 01:28AM)
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.
Message: Posted by: DWRackley (Apr 21, 2010 10:34PM)
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 [i]frequency[/i], 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.
Message: Posted by: Caspar (Dec 21, 2010 07:02PM)
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.
Message: Posted by: Enzo (Dec 22, 2010 08:17PM)
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.
Message: Posted by: Mr. Mystoffelees (Dec 23, 2010 08:58AM)
[quote]
On 2010-12-21 20:02, Caspar wrote:
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.
[/quote]

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
Message: Posted by: mightydog (Jan 23, 2011 07:40PM)
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
Message: Posted by: mightydog (Jan 23, 2011 08:01PM)
http://www.youtube.com/watch?v=PdrqdW4Miao

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

mightydog
David
Message: Posted by: mightydog (Jan 23, 2011 08:49PM)
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
Message: Posted by: Jonathan Townsend (Jan 23, 2011 10:18PM)
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.

[quote]
On 2009-04-02 23:44, Xaethia wrote:
Hello,

A couple weeks ago I was looking in Ripley's Believe It or Not. There was a little article and a picture of someone using a machine that electicity was coming out and it wasn't harming her/him (can't remember).

I tried to do a little research and as far as I got was I THINK (!!!) it was a machine invented by Telsa - for he experimented with hiqh-frequency electricity. It also said that high-frequency electricity doesn't harm our skin.

In The Prestige (the film) the machine that makes the main character clone him uses high-frequency electricity (my guess, for it does not harm the him).



What is this machine called?
Has anyone got any idea how much a machine like this would cost? (I am guessing quite a bit)
Why doesn't high-frequency electricity harm our skin?

Xaethia
[/quote]

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 [url=http://en.wikipedia.org/wiki/High_voltage#Sparks_in_air]33000v/cm or 100,000V/inch.[/url] 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
Message: Posted by: htmagic (Nov 11, 2016 09:43PM)
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/
Message: Posted by: Pop Haydn (Nov 16, 2016 02:10PM)
A Tesla Coil can be used to bend the force of gravity itself:

[youtube]5bncL4-qnBM[/youtube]
Message: Posted by: htmagic (Nov 17, 2016 06:17AM)
[quote]On Nov 16, 2016, Pop Haydn wrote:
A Tesla Coil can be used to bend the force of gravity itself:

<SNIP> [/quote]
Pop,
Awesome Tesla coil! Did you build it yourself?
I couldn't see any details on it. Is it a solid state coil?
I didn't hear any spark gap firing on it but the hum that came through the PA system.
Cute demonstration with your Tesla girl. Very original act. Wish I saw it in person...
Message: Posted by: Pop Haydn (Nov 17, 2016 09:52AM)
Here's a closer look:

[youtube]A_iy7HxPADA[/youtube]

I built it myself. The original kit was made by Sophie Evans, and then I blew it up. So I had to remake the whole thing all over, using just the box and the original transformer.

The top box is the Tesla Coil, the lower box is just a sound effects and lights machine that can make it seem the coil is on when it isn't.
Message: Posted by: Pop Haydn (Nov 17, 2016 09:57AM)
Sophie Evans as Tesla Girl:

[img]https://s-media-cache-ak0.pinimg.com/564x/27/a7/4a/27a74a96836ccd7ad5e2f6b560f024cc.jpg[/img]

Liberty Larsen:

[img]https://s-media-cache-ak0.pinimg.com/564x/0d/0b/73/0d0b737a775682b53bdef90d6cb5b1d6.jpg[/img]
Message: Posted by: htmagic (Nov 17, 2016 11:36AM)
[quote]On Nov 17, 2016, Pop Haydn wrote:
Here's a closer look:

<SNIP>

I built it myself. The original kit was made by Sophie Evans, and then I blew it up. So I had to remake the whole thing all over, using just the box and the original transformer.

The top box is the Tesla Coil, the lower box is just a sound effects and lights machine that can make it seem the coil is on when it isn't. [/quote]
Pop,
That's awesome! Very cool!

Wish you had that when you visited us at the Winter Carnival of Magic in Pigeon Forge, TN.
So the bottom is a spark gap you turn on with the high voltage transformer?
I don't think a solid state coil could take the abuse you were showing it and the sparks looked like they were biting you even through the Hot Hands gloves.

So is Tesla girl actually connected to the secondary coil through the pad? I couldn't tell. Is that how she lit the matches? I didn't see any sparks out of the fingertips and it's best to use metal thimbles to protect against spark burns.

Again, very cool act.
Message: Posted by: htmagic (Nov 17, 2016 11:45AM)
Pop,
Pretty cool...

[img]https://pophaydn.files.wordpress.com/2012/12/21st_century_225_button.jpg[/img]
Message: Posted by: Pop Haydn (Nov 17, 2016 01:13PM)
[quote]On Nov 17, 2016, htmagic wrote:
[quote]On Nov 17, 2016, Pop Haydn wrote:
Here's a closer look:

<SNIP>

I built it myself. The original kit was made by Sophie Evans, and then I blew it up. So I had to remake the whole thing all over, using just the box and the original transformer.

The top box is the Tesla Coil, the lower box is just a sound effects and lights machine that can make it seem the coil is on when it isn't. [/quote]
Pop,
That's awesome! Very cool!

Wish you had that when you visited us at the Winter Carnival of Magic in Pigeon Forge, TN.
So the bottom is a spark gap you turn on with the high voltage transformer?
I don't think a solid state coil could take the abuse you were showing it and the sparks looked like they were biting you even through the Hot Hands gloves.

So is Tesla girl actually connected to the secondary coil through the pad? I couldn't tell. Is that how she lit the matches? I didn't see any sparks out of the fingertips and it's best to use metal thimbles to protect against spark burns.

Again, very cool act. [/quote]

The copper mat she stands on is not really connected to anything. It is very dangerous to have a direct connection to the output of a Tesla Coil. Sophie and I used to do it in trade shows in Vegas, combining the Electric Lady with the Georgia Magnet. Sophie married an electronics engineer and emergency room physician. Rob told us that there was a good chance of a spark jumping from the primary coil to the secondary coil, releasing a high amperage current directly through the toroid. It could kill a person or do serious internal energy. We decided to put the Tesla Coil in the background and just use tricks to make it look like she had electric current, and let the Georgia Magnet routine be the main deal.

The first time we did this new version without the Electric Lady part at the World Steam Expo in Dearborn, a spark jumped the device and burned a line in the pvc of the secondary coil all the way up to the toroid. If Sophie had been on the device when that happened, she would have been seriously injured or killed. We had to rebuild the device.

The Tesla Coil is not solid-state. It has a spark gap that shows through the glass port on the upper box.

The lower box has sound and strobe light effects to simulate a spark gap.
Message: Posted by: Pop Haydn (Nov 17, 2016 01:21PM)
Here is Sophie Evans as Tesla Girl:

[img]https://pophaydn.files.wordpress.com/2016/08/9744172_orig.jpg[/img]
Message: Posted by: htmagic (Nov 17, 2016 01:54PM)
Pop,

Very cool! If your show ever comes back east near TN or KY, please let us know. We'd love to see this act.
Once a sprak track burns in the PVC form, the secondary coil is ruined. We've had to rewind many a coil (sigh).

So does Sophie pick men up by the ears like the original Georgia Magnet?
Message: Posted by: htmagic (Nov 17, 2016 08:02PM)
Pop,

Did she use the Barton text as a guide for her act?
Seems like a number of the things she does are outlined in the text.
Message: Posted by: Pop Haydn (Nov 17, 2016 09:02PM)
We used a lot of sources. The Barton-Wright book on strong man stunts was not as helpful as the autobiography of Lulu Hurst.

http://www.pophaydn.com/magnetized-water.html
Message: Posted by: htmagic (Nov 17, 2016 09:38PM)
Pop,

Love it!
Your site has a lot of good information on it. It has been a while since I've seen it and you've added to it.

[img]http://www.pophaydn.com/uploads/7/7/6/6/7766194/3737337_orig.jpeg[/img]
This photo reminds me of the Wizard of Oz...
Message: Posted by: htmagic (Nov 17, 2016 10:16PM)
Pop,

I also like your tribute to Tesla on your website.

Here's a little treat. I took this photo of one of the original Tesla motors that he built and this was at Columbia University. They studied his invention.
Over 100 years old and it would still work. The gutta percha insulation is cracked.
This photo was taken at a Tesla Conference in Long Island, NY in 2006.

[img]https://scontent.fbna1-2.fna.fbcdn.net/t31.0-8/15129578_10211708310410264_6155376948265843566_o.jpg[/img]

And then we visited the Wardenclyffe site after the conference. Here's a picture of the building years ago.

[img]https://teslauniverse.com/sites/default/files/styles/full_width/public/images/dsc00670.jpg[/img]

And here's a closeup of the chimney that I took. A spot light was added to the ornate cage.

[img]https://scontent.fbna1-2.fna.fbcdn.net/t31.0-8/15128887_10211708311210284_5958787803744602540_o.jpg[/img]

The Wardenclyffe site was eventually bought by Peerless Photo and was a Superfund site.

[img]https://scontent.fbna1-2.fna.fbcdn.net/t31.0-8/15042066_10211708311610294_8799275204206572368_o.jpg[/img]

A private group was trying to buy the site and building and turn it into a museum.
Message: Posted by: Pop Haydn (Nov 17, 2016 11:06PM)
[img]https://upload.wikimedia.org/wikipedia/commons/3/3a/Wardenclyffe_Tower_-_1904.jpg[/img]
Message: Posted by: htmagic (Nov 22, 2016 10:22AM)
Pop,

So you're performing at the Magic Castle this week?
How's it going?
Message: Posted by: Pop Haydn (Nov 23, 2016 12:39AM)
Not this week. Two weeks ago. It went well. I always have fun in the Palace. I was working with Lindsay Benner and Mark Kalin and Ginger. They are lovely people and kick ass acts.
Message: Posted by: htmagic (Nov 23, 2016 07:35PM)
[quote]On Nov 23, 2016, Pop Haydn wrote:
Not this week. Two weeks ago. It went well. I always have fun in the Palace. I was working with Lindsay Benner and Mark Kalin and Ginger. They are lovely people and kick ass acts. [/quote]
Pop,

That's sounds so cool. I wish I could have seen it.

I wish you all a Happy Thanksgiving!
Pop, with self-basting turkeys, instant potatoes, and microwave cooking, Thanksgiving must be quite different than in the 1800s where you came from.
Bet they never even heard of Black Friday...
Message: Posted by: Pop Haydn (Nov 23, 2016 08:33PM)
[img]http://3.bp.blogspot.com/-z6TGuAflWwg/UpdrSem-X8I/AAAAAAAAgXA/Cplmt9ZGJ1g/s1600/1890s+THANKSGIVING+CARD.jpg[/img]


Here is video of my Palace Show a couple of weeks ago:

[youtube]gdezz_8UQTg[/youtube]

[youtube]vBw7pgBNYA4[/youtube]

[youtube]Vu7x00uKOP4[/youtube]
Message: Posted by: htmagic (Nov 23, 2016 09:21PM)
Pop,

I really like your greeting card! Takes us back to a simpler era, doesn't it?

Those tricks are all classics. I really like the Mongolian Pop Knot.
Tomorrow I will make the turkey disappear! Except I will get help from my family! lol
Message: Posted by: htmagic (Dec 1, 2016 02:28PM)
Pop had this on his page but I would like to share it here since it deals with Tesla coils and high frequency electricity.
Pretty cool Tesla stuff!

[youtube]_fTC_Ud_k3U[/youtube]
Message: Posted by: That1MagicGuy (Dec 6, 2016 09:17PM)
Wow, I want to make a tesla coil as well, it looks incredible.
It's there a instructor manual on how to make this safely out there?
Message: Posted by: Pop Haydn (Dec 7, 2016 12:20AM)
There are places that sell kits to build tesla coils. They tell you how to build them safely, not always how to use them safely. Do as much study as you can.
Message: Posted by: htmagic (Dec 7, 2016 07:06PM)
[quote]On Dec 7, 2016, Pop Haydn wrote:
There are places that sell kits to build tesla coils. They tell you how to build them safely, not always how to use them safely. Do as much study as you can. [/quote]
Pop is exactly correct. The spark gap primary circuit of my coil is 15 kV and the amps are enough to kill you. Plus capacitors can retain a stored charge for a long time.

The http://onetesla.com/ site offers decent kits but previous experience in soldering and building electronic kits are required. They give theory and safety tips as well. It is a solid state coil so a little safer than the ones that use neon sign transformers in the primary circuit.

Here's another site that offers solid state tesla coils.
It uses a 12 volt power supply.

http://www.high-techmagic.com/ez-catalog/X348591/4/MTC-001?layout=system:layout_0100.xsl
Message: Posted by: htmagic (Jan 2, 2017 07:40PM)
Happy New Year!
For New Year's eve, I loaded up Auld Lang Syne on my musical tesla coil and rang in the new year as we watched the ball drop on TV.
Anybody else do anything special for New Year's?
Message: Posted by: Pop Haydn (Jan 2, 2017 07:56PM)
I blew up my liquid capacitor on my Neon transformer based system. This covered the inside of my metal box with dangerous PCBs. It was a dangerous and messy cleanup. We replaced the capacitor with a dry one. That is another safety consideration.
Message: Posted by: htmagic (Jan 12, 2017 08:46PM)
Pop,

The older capacitors did have PCBs in them. The new ones don't.
Yeah, I've stressed coils before and blew the capacitors. Exciting!
Good way for the coil to end in a bang!
I've been having fun playing with my solid state coil lately.
The sparks are not as hot or as long as my older spark gap coil.
But the old one doesn't play music and is not as portable as this one is.
And it's a different type of buzz but still fun to watch, listen, and to play with.
Message: Posted by: htmagic (Jan 12, 2017 09:03PM)
Pop,

Does your Tesla coil use just one neon transformer?
Mine has two 15 kV Franceformers in parallel.
Yeah, the primary is definitely lethal.
And the neon transformers are so heavy, I put them in a wheeled metal cart.
Message: Posted by: Pop Haydn (Jan 13, 2017 12:07AM)
[quote]On Jan 12, 2017, htmagic wrote:
Pop,

Does your Tesla coil use just one neon transformer?
Mine has two 15 kV Franceformers in parallel.
Yeah, the primary is definitely lethal.
And the neon transformers are so heavy, I put them in a wheeled metal cart. [/quote]

Mine is just one transformer. The Secondary coil is only a foot tall. Sparks are 8-10 inches. 160,000 volts.

Just saw this today:

[youtube]VeFNg0Sz10I[/youtube]
Message: Posted by: htmagic (Jan 13, 2017 08:42AM)
Pop,

'The Special Head show goes beyond a traditional magic show.'
THAT's the understatement of the year! lol
The lightning from the fingertips is a cool touch. Actually the spark coming off the fingertips is hot enough to burn the flesh.
It is annoying. That's why you use metal thimbles over the tips so the spark can jump off them and not burn a hole in the flesh.
Although the Hutchinson effect is an actual thing, he is not using it in his levitation.
And the Hutchinson effect may have been discovered by Tesla years ago when he was involved in the Philadelphia effect.
Of course, that went horribly wrong and Tesla warned them not to have the crewman on the ship.
John Hutchinson not only could levitate objects but wood was melded into metal as if it melted together. Even he has had difficulties trying to recreate the effect.

Thanks for sharing a cool video...
Message: Posted by: htmagic (Jan 28, 2017 11:05PM)
My oneTesla coil has a MIDI port on the control box.
I can plug in a MIDI cable from a keyboard and directly control the coil through the keyboard.
If only I knew how to play keyboard! lol

Apparently there is a MIDI to USB cable where you can connect a computer to a keyboard and import or export MIDI files from the keyboard or computer.
So until I get better on the keyboard, I guess I could play chopsticks on the keyboard and ultimately through the Tesla coil...
Message: Posted by: htmagic (Jan 28, 2017 11:21PM)
I stumbled across this video of two people in special suits dueling each other on Tesla coils.
There is some serious power here!
Some ninja moves with high voltage. What's not to love?
Check it out here:

[youtube]WMYyBBym55Q[/youtube]

Enjoy!
Message: Posted by: htmagic (Feb 3, 2017 09:27PM)
Well I didn't know Tesla coil and plasma balls could make a fashion statement but apparently they can.
And such a pretty one too.
Pop, you ought to see if she can fill in for Tesla girl when she gets sick! lol

[youtube]PDp-UtrwjcU[/youtube]
Message: Posted by: htmagic (Apr 9, 2017 08:40PM)
More Tesla coils.
This time from a hand held spark tester. Although it is a type of Tesla coil, it is an induction coil that produces a high voltage spark.
The buzzer type adjuster on the end of the induction coil was the oscillator of sorts and the kickback would cause the voltage multiplication.
They used it in hand held Violet Ray devices as mentioned here:

[youtube]m4n_dkmLWII[/youtube]

Enjoy!
Message: Posted by: htmagic (Apr 25, 2017 11:03AM)
Now this thread is about high frequency electricity and the Tesla coils that produce it.
Now Tesla coils are named for its inventor, Nikola Tesla.

I stumbled across a video that celebrates the incredible genius of this Wizard of Electricity, The Man Who Lit The World.
Come watch this magical adventure where digital technology and illusion will bring to life one of the world's greatest inventors.

[youtube]th8Zo8xCK-g[/youtube]
Message: Posted by: andrew124C41 (Aug 26, 2017 09:10PM)
My grandfather, Hugo Gernsback, was a friend and colleague of Tesla and published his autobiography, My Inventions, in his magazine, the Electrical Experimenter. Many, many years ago I worked on a project trying to develop a version of Zombie that used a globe made of borosilicate glass filled with argon and neon. My plan was to use a variant of a Tesla coil to light it wirelessly. However, my full time avocation as a physician prevented me from finishing it. The difficulty at the time was making it quite. The rotating spark gap was too noisy. I could probably make I today without the rotating gap.
Message: Posted by: htmagic (Aug 27, 2017 05:58PM)
OMG!
I LOVE Hugo Gernsback publications!
My late father used to subscribe to and collect Radio News magazines.
He later bound 1 years' worth of magazines in a bound version, like a hardback book, sewn and glued just a a book with hard covers.
He used gold foil and a stamp to describe the title and year of the publication.
I still have those musty journals in my bookcase.
When he bound them, I think he removed the full pages of ads to trim the size of the books.
But I liked reading the old ads and their claims as well. It is amazing to look back into history during the 40s and 50s.

I also have some reprints of the Electrical Experimenter from August 1917 and it is interesting to read Nikola Telsa describing a high-frequency "electric ray" for locating submarines.

"The Reflected Electric Ray Method Is Illustrated Above; the High- Frequency Invisible Electric Ray, When Reflected by a Submarine Hull, Causes Phosphorescent Screens on Another or Even the Same Ship to Glow, Giving Warning That the U -boats Are Near."

This is NOT sonar, but radar! And Tesla was describing it in WWI, not WWII when it was used!
Amazing!

BTW, I HAVE a hand held plasma ball and was thinking a doing a zombie routine with it. But the plasma ball itself is heavy and fragile and one would need steel fingers to keep that thing aloft! LOL

But a flickering neon lamp that looks like a flame on a candle IS entirely possible and I played around with that. I developed a battery operated power supply that would feed into the neon and it is totally silent and solid state. No rotary spark gaps needed! LOL
Message: Posted by: andrew124C41 (Sep 13, 2017 05:21PM)
[quote]On Apr 2, 2009, Xaethia wrote:
Hello,

A couple weeks ago I was looking in Ripley's Believe It or Not. There was a little article and a picture of someone using a machine that electicity was coming out and it wasn't harming her/him (can't remember).

I tried to do a little research and as far as I got was I THINK (!!!) it was a machine invented by Telsa - for he experimented with hiqh-frequency electricity. It also said that high-frequency electricity doesn't harm our skin.

In The Prestige (the film) the machine that makes the main character clone him uses high-frequency electricity (my guess, for it does not harm the him).



What is this machine called?
Has anyone got any idea how much a machine like this would cost? (I am guessing quite a bit)
Why doesn't high-frequency electricity harm our skin?

Xaethia [/quote]

I don't know exactly what you are describing as far as Rippley's is concerned. What I can say is that the general nature of a type of electrical phenomenon you are describing that is not harmful to humans is high frequency current such as generated from a Tesla Coil. Over the years I have had a number of ideas to use something like this but at the time the noise of the rotating spark gap was prohibitive.

My grandfather, Hugo Gernsback, published Tesla's Autobiography, My Inventions, in his magazine, the Electrical Experimenter. (August 19th was the 50th anniversary of my grandfather's death and I will be launching a website and the magazine will be available there.)
Message: Posted by: htmagic (Sep 13, 2017 06:00PM)
Andrew,

Talk about necro'ing a post! It is indeed a Tesla coil but they CAN be harmful in humans if not constructed properly. The early Tesla coils used series gaps or rotary spark gaps as the oscillators in the primary high voltage circuit. Later Tesla coils used vacuum tubes and newer coils use solid state oscillators which is more quiet except for the spark out at the end of the torroid. Most people say the high frequency high voltage is harmless due to the "skin effect", however, one of the Tesla coils I built using a series spark gap introduced a 60 Hz ripple across the secondary. And that CAN be dangerous.

BTW, the image of Tesla sitting in a chair in the space between the primary and secondary coils of his Colorado Springs magnifying transmitter is actually trick photography. A double exposure was made where Nikola Tesla is shown sitting in a chair inside his coil with the power off. He got out of the chair and then turned on the machine and took another picture with the sparks rolling all around. Although he wore thick cork heels to insulate him from the ground (he was already over 6 ft tall), he never sat inside the coil while it was operating. Tesla's demonstrations with high frequency and high voltage was done in New York (prior to Colorado Springs) using a much smaller transformer (more like a neon sign transformer) in a box filled with mineral oil.

Tesla was smart about using thick cork to insulate him from the ground. One time when I was playing with my Tesla coil that used to throw 4 ft sparks, I took a fluorescent bulb and drew the spark from the top of the coil. It went through my body and out the bottom of the leather sole of the shoes I was wearing. And jumped into the foot switch (which was grounded) that I used to turn the coil on or off. Fun times! But a little painful and you could see where the spark jumped out my sole and left a little burn mark...
Message: Posted by: andrew124C41 (Sep 14, 2017 11:54AM)
Well, excuse me for breathing.
I was aware of all of this.
I picked the picture simply for its dramatic effect.
Building and using Tesla Coils is not something that should be done by someone who is not thoroughly familiar with HV.
There are many potential problems if details are not adhered to.
I have built them with both spark gaps and rotary gaps. The late Bill Wysock built the rotary gap for me and helped me get a toroid.
I was a member of the Tesla Coil Builder's Association and saw quite a few interesting demonstrations of coils and magnifiers.
Message: Posted by: htmagic (Sep 14, 2017 01:55PM)
[quote]On Sep 14, 2017, andrew124C41 wrote:
Well, excuse me for breathing.
I was aware of all of this.
I picked the picture simply for its dramatic effect.
Building and using Tesla Coils is not something that should be done by someone who is not thoroughly familiar with HV.
There are many potential problems if details are not adhered to.
I have built them with both spark gaps and rotary gaps. The late Bill Wysock built the rotary gap for me and helped me get a toroid.
I was a member of the Tesla Coil Builder's Association and saw quite a few interesting demonstrations of coils and magnifiers. [/quote]
Andrew,

I've seen this picture so many times before and being the grandson of Hugo Gernsback I suspected you might already have known the back story. But from the original post you necro'ed that person probably did not and maybe others.

Bill Wysock was quite the builder and I believe his 13M Tesla coil that went up for sale in 2009 was one of the largest coils in the world. When he passed in 2013 he was sadly missed by those in the Tesla community. I used to belong to the TCBA several years ago...
Message: Posted by: andrew124C41 (Sep 14, 2017 02:42PM)
Necro'ed I had to look this up. :-)
I was supposed to go to Ed Wingate's Teslathon a couple of years ago but could not make it.
BTW, I saw your website. I used to be into neon years ago. I still have an orignal James Falk Plasma Sphere. I met him and toured his factor in NJ back in the late 80s. I heard about the 13M being sold. I have no idea what it sold for.
Message: Posted by: htmagic (Sep 14, 2017 02:51PM)
[quote]On Sep 14, 2017, andrew124C41 wrote:
Necro'ed I had to look this up. :-)
I was supposed to go to Ed Wingate's Teslathon a couple of years ago but could not make it.
BTW, I saw your website. I used to be into neon years ago. I still have an orignal James Falk Plasma Sphere. I met him and toured his factor in NJ back in the late 80s. I heard about the 13M being sold. I have no idea what it sold for. [/quote]
Andrew,

I don't know what Wysock's monster coil went for but considering it was reported that the rotary spark gap cost him over $6000 to build in 2009 dollars, I'm sure it went for a pretty penny (and LOTS of them)! I wonder who ended up with his coil and I wonder what his power bill would be? LOL