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Build Your Own Tesla Coil
screenbert writes "Ever wanted to keep stray dogs or neighbors from trampling your backyard, but
just couldn't find the system to really deter them? Well this
site shows how they built
a bi-polar Tesla Coil system. I've always loved the Tesla coils on C&C when
they'd zap the units as they went by.
"
Much as I hate to reply to a troll, there are a few people who might read this and believe it!
While there was a harmonic device which Tesla built which could indeed shake a building apart, this was not his intent with the Tesla coil.
His plan was actually distributing energy on a large scale without wires. Take a look at his Pike's Peak project.
I believe you are incorrect. You're talking about the Telsa "Earthquake machine" oscillator, which was a tunable steam- or electrically-powered weight. There's a book about it, IIRC it's called the "Tesla Earthquake Machine" or something like that, and includes plans to build your very own.
Tesla, upon inventing the oscillator, attached it to a bar of the finest steel he could get, and within a few minutes the oscillator had found (been set to?) the resonating frequency of the bar and shattered it. Tesla then attached it to a pillar that was driven into the earth at his laboratory [keep in mind that his lab, and several other New York buildings, were built on a patch of sand, IIRC] and turned it on. He took a crowbar to it when the buildings across the street started to shake.
Keep in mind this device was no bigger than a 2-liter pop bottle, if I rember correctly.
The Tesla Coil is a high-frequency, high-voltage transformer, and shares few parts or concepts with the "earthquake machine."
This
The tesla coil described in the page is not really of much practical use.
:-(
It operates at a high voltage and low current. This means that, yeah, it looks impressive, but any actual damage it could cause would be extremely limited. If you want something like the tesla coils in C&C, you have some problems to overcome.
The first is something that is directional. The tesla coils in C&C were far beyond today's technology, since electricity naturally flows to the nearest earth.
To really hurt something or burn something, you're looking at throwing at least 100 amps from the coil. This is far away from the 100 milliamps that current tesla coils use. But for the fun of it, let's work out what sort of power you'd need to really cause some serious damage.
So, we have the 100 amps. What about the voltage? 10,000 volts is the right sort of voltage to be able to shoot a beam of tesla lightning about 20 metres. This is calculated by taking the SU air density of 2.5Fd per metre, and multiplying that by (current / air impedence), or (100 / 0.0279)..
So, 2.5 * (100 / 0.0261) = 9,578.54 volts.. close enough to 10,000 volts anyway.
And 10,000 volts at 100 amps? You do the math. You are talking about a serious amount of electricity.
And don't forget.. the thing would have a constant load! When the coil isn't zapping intruders (okay, it's a stupid concept but I'm just pointing out the practicalities).. you're still sucking up several megawatts of power with it just going straight back to earth!
So, this is a great idea, and a cute trial.. but you're never going to get a tesla coil that can really injure people like in C&C. It's all just pretty patterns in the sky for now...
mogorific carpentry experiments
Look here, and at the links within:
http://www.hills2.u-net.com/tesla.htm
The transmission of electricity via tesla coils had absolutely nothing to do with the arcs of electricity that shot off of it. He wanted to transmit power via EM radiation.
Hold a flourescent lightbulb near a tesla coil and it lights. It has nothing to do with "arcing."
Comment removed based on user account deletion
We put two bent copper rods for the spark to jump between. The spark would run up and down between these rods like old mad-scientist movies.
Sounds like a Jacob's ladder to me!
My science fair Jacob's ladder used a neon sign power supply with 50,000 V
SCO (noun.)- A Slimy Corporate Ogre. Often seeks free money.
I would like to politely remind you that resistance causes a voltage drop but no change in current :) You could concievably suck up all 100ma and be in ALOT of pain :)
Religion is a gateway psychosis. -- Dave Foley
As somebody who has built several tesla coils, I though I might be able to provide some information on this topic. A tesla coil is basically a high frequency transformer. They come in two varieties, traditional and solid state. A schematic for a traditional tesla coil can be found here. The main for a traditional tesla coil is usually a neon sign transformer, or NST as we call them. The capacitor is often a milspec jet engine ignition capacitor or a leyden jar made out of beer bottles. Solid state tesla coils are similar, except they use a less powerfull main transformer and use a flyback transformer (found on most tv's, although flyback's from the 50's and 60's work best, as they don't have as many safety devices) as the resonator. Just be forewarned, the information on the site I linked to is about 5 years out of date.
There's no sig like SIGSEG
>10,000 volts is the right sort of voltage to be
>able to shoot a beam of tesla lightning about 20
>metres.
Uh... not quite. It takes about 2,000 volts per centimeter of air that you want the current to flow through. I have a 15,000 volt transformer and it can create arcs around 3 inches or 7 1/2 centimeters. To get 20 meters you'd need about 4 million volts. (20m * 2000 V/cm = 4E6 V)
----- "I'm still sane on three planets and two moons."
One hopes that the above poster is intentionally posting pseudoscientific nonsense... but a few people seem to have taken it seriously... so...
.1 Amp. That will stop someone's heart.
While these Tesla coils are probably harmless, to do damage to a human you need not 100 amps, but less than
Furthermore, let us say that you want to put 100 amps into something from 20 meters. First of all, 10,000 volts isn't anywhere close (you calculations are way off - in fact, they are sheer nonsense!) A few megavolts at a minimum would be required.
But... as far as power delivered to the load... the resistance of the air is uninteresting. Once the arc starts, the resistance drops dramatically in the plasma. Thus one could deliver 100 amps at 20 meters with a lot less power than you calculate.
The statement that electricity naturally flows to the nearest earth is likewise fallacious. Electricity flows (or tries to flow) across potential differences. If you hook one end of a potential difference to the earth, electricity from the other end will certainly try to flow there. But if the Tesla coil is insulated from the earth, the electricity will have no particular interest in flowing to the earth!
All in all... very cleverly stated nonsense.
Naughty of you (or ignorant of you).
The only good weather is bad weather.
The statement that electricity naturally flows to the nearest earth is likewise fallacious.
Yes, as is the assertion that electricity somehow âoechooses a path of least resistance.â This is also an example of the anthropomorphic fallacy â" attributing human-like qualities to something inanimate.
In an electrical circuit, given an electric potental (i.e., a voltage), current will flow through all available paths. The magnitude of the current in each branch is inversely proportional to the resistance (or impedance if we consider more than simple DC) so it can often seem as if somehow those lazy electrons survey their options and decide to take the easiest path.
The problem in understanding usually is emphasized when you deal with paths of conduction through air or other materials that are normally insulators. The issue here is that the breakdown voltage of air and most nonconductors is very large. Unless the electric field strength exceeds this threshold then the material is an insulatore. In these cases there are no alternate paths, except for the unwitting human who happens to come too close, and gets a shock. So it's no so much that his body formed the path of least resistance; more like he formed a path period where before there were none.
Hm.
I'm always wary of these sites. They show all this electricity zapping round, and guys with electrofingers.
Only problem is this: Unless a tesla coil is specifically built for this purpose, the skin effect does not work on telsa coils. You actually cook your organs.
I think it's highly irresponsible to blaze things like tesla coils.
I've built one, I've used one, and had an enjoyable time, but safety must be the first priority, not pretty pictures.
For more information about the dangers of tesla coils, Here[Chip Atkinson's Safety sheets]
modern flybacks use a integrated diode. If you can find a old tube tv you will have more fun. You mentioned burning through paper. I remember burning through a penny.