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Tesla Coils
A Tesla coil is an air cored resonanttransformer. It works by matching all the components in the system so that they resonate at the same (or harmonic) frequency. The end result is that thevoltage input is stepped up by a tremendous amount.
Example Tesla Coils
Tesla Coils can come in many forms. These two examples are ones we have made for the DIY Devices section. The image in the right shows a battery powered tesla coil which uses an ignition coil driver to charge the tank capacitor. The leftmost image above shows the 'Plasma Gun' which is a much smaller hand held version of the other Tesla Coil shown on the right.
Also check out our SRSG Tesla coil rated at 1kW!
How a Tesla Coil Works
This image shows a simple schematic diagram of a Tesla Coil. There are numerous configurations to choose from. Using this configuration, the TC is powered from a high voltage DC source, such as a rectified output from a neon sign transformer (NST). The device operates in a cyclic manner. This means that a series of changes occur within the circuit, until it is reset and the next cycle begins.
First of all, the capacitor (C1) is charged by the power source (HVDC). When the voltage across the capacitor is high enough, the air in the spark gap (SG) breaks down and allows a current to flow. This forms an LRC (inductance/resistance/capacitance) resonant circuit until the voltage across the capacitor drops sufficiently to quench the spark gap. This all takes a fraction of a second and completes one cycle. The capacitor will then begin charging again. But what about the rest of the circuit? First of all we must understand more about the LRC circuit described above.
When the air in the spark gap breaks down, it is acting like a switch connecting the charged capacitor in parallel with the inductor or coil (L1). As the initial current flows around the LC circuit, energy from C1 is stored in a magnetic field created by L1. When the capacitor is discharged, the magnetic field will collapse. This collapsing field will cause a current to flow in the opposite direction as before, therefore recharging the capacitor. This process will then repeat, causing the current to oscillate back and forth until the energy is dissipated by losses in the circuit and the spark gap quenches. This cycle happens within the other cycle described before, i.e. every time the spark gap fires (1st cycle) the current will oscillate back and forth between C1 and L1 (2nd cycle). The frequency at which the 2nd cycle oscillates is determined by the physical values of the components. This is known as the resonant frequency. The second part of the circuit (C2 and L2) must be constructed so that its natural resonant frequency is the same as the previous part.
A Brief History of Nikola Tesla and the Tesla Coil
The Tesla Coil (TC) was invented in 1891 by Nikola Tesla. It is one of many ingenious devices he created which have paved the way in which our technology has developed. The AC electrical grid, radio transmitters and car ignition systems we use today are derived directly from Tesla's inventions. So why have most people never heard of him? History seems to record two different versions of Tesla. One is that he was a crackpot inventor and that he made unsubstantiated claims of fantastical inventions, whereas the other version is of an under appreciated, misunderstood genius. It is the former that seems to be the official view, although it now seems as if the true Nikola Tesla was a combination of both these opinions.
Nikola Tesla was born in Smiljan, Croatia in 1856. As a small boy, Tesla had a problem where certain things could trigger visual memories and they would appear to him as if they were real. These images could persist, therefore obscuring his true vision. He learned to control these images before he matured, and could use this 'gift' to his advantage.
He had an extraordinary photographic memory, which allowed him to easily learn six languages. He used his visualization skills like we use a CAD program today. He states in his autobiography that he was able to construct machines, test their performance, and disassemble them to check for ware; All in his mind!
Rotating magnetic fields and resonance fascinated Tesla. He often worked continually on his inventions and theories, only sleeping for two hours per day. Tesla always eat alone and woul feel the need to measure exactly the amout of food he was about to consume. He was also obsessed with germs, and avoided touching utensils directly. It is this obsessive behavior gave people an impression that he was a 'crackpot'. It could also have led to his mental decline in his later years.
In his days of invention, Tesla came up with some astonishing ideas and devices. Often he was misunderstood by the rest of the scientific community, as is ideas were so far out from anything that they understood themselves. Tesla made claims that he could transfer energy around the globe without the use of wires, and that the energy its self could be obtained freely from the environment without the need for fuel. These ideas made him unpopular with the establishment, as such devices would reduce their political power and overall wealth. It is only more recently that some of this work is being taken seriously. There is much conspiracy theory around these subjects, but it will not be discussed here. You can learn more about the science involved by going to the physics section of this site. It is also recommended that you do further reading on Nikola Tesla if you are interested in this subject.
Nikola Tesla's invention of AC electricity is what is used to power homes today yet many people connect the name Edison with electricitys origins. Both Tesla and Edison were competing with eachother for the promotion of their ideas as the best technology. Edison was trying to promote DC electricity as the best way to power homes and went to some extreem lengths in an attempt to discredit Teslas work in order to make his own appear superior. The video shown below was filmed in 1903 when Edison electrcuted to death an elephant as a cruel stunt to try to show the danger of AC electricity.
The fact is that Teslas AC electricity is actually safer in many ways. Edison just made the current very large. Such large currents would kill regardless of AC or DC. Most of us learned about Edison at school but rarley is it mentioned what a cruel and dishonerable man he was. Tesla sought to make the world better for all, Eddison sought wealth and power. Unfortunatley money usually wins more power to change things than good will does.
How to Make a Tesla Coil
The photo on the left shows electrical discharge through a small flame on the top sphere of a homemade, battery powered Tesla Coil. The aim of this design was to get the highest voltage (or longest arcs) possible from a singe self contained unit. This coil operates from 12V or 24V SLA batteries. A pair of car ignition coils are used to provide around 20kV for charging the capacitor bank. The ignition coils are driven by a variable frequency square wave from a 555 timing chip and four large transistors (2N3055).
More Info: DIY Homemade Tesla Coi
The information provided here can not be guaranteed as accurate or correct. Always check with an alternate source before following any suggestions made here.
Are there any safety issues? If so what are they?
Thanks for your help.
It can be 'safer' to run a TC from batteries, but it could still quite easily kill you. Any device that charges capacitors to high voltage can be instantly lethal.
This mini Tesla Coil runs from a small 12V battery. Internally there are still capacitors being charged to thousands of volts so touching the wrong part could be nasty. A bleeder resistor is usually placed across the tank capacitor so that it wont hold charge for very long after being switched off.
You can measure the frequency of an LC circuit by connecting it to the scope and applying an electrical pulse. This pulse should set the circuit ringing and you should be able to see the result on your scope.
The primary circuit is a parallel LC circuit which will give maximum reactance at it resonant frequency. The secondary coil and topload form a series LC circuit which will give minimum reactance at the resonant frequency.
If you apply a signal source across an LC circuit, you can measure the high and low points while adjusting the frequency of your source. At the resonant frequency of your LC circuit the voltage measured on the scope will be either higher or lower than at other frequencies depending upon if it is series or parallel LC.
If you know the frequency of the secondary circuit, you can set a signal generator to match this and apply it to the primary LC circuit. You can then adjust your tapping point on the primary coil until you see the signal on your scope at its maximum level.
What would be a good frequency to run my ignition coil?
Thank you very much.
The frequency depends on your coil and its load so I can't really answer your question. A variable frequency source is often used so it can be tweaked until the best output is found.
and he also imagine thew germs going through his arms NO OFFENSE
The ball is not a Van De Graff generator ball but it serves a similar purpose. It acts as a small reservoir for electrical energy and it also helps control the way the arcs are formed. The ball is referred to as a 'topload' and it can be any shaped piece of metal but smooth round shapes work best.
The coils on this site use DC because the ignition coils used for the HV source will not charge a capacitor in the same way as a mains powered transformer.
A mains powered transformer is driven by a sine wave and with enough current that it can charge a tank capacitor on each half cycle.
can you use a 35kvdc, .o30uF capacitor with a 12kv neon transformer. The previous cap was a 15kvacw with a 15 kv transformer and worked well for a while then blew.
Yes.
The N3RD,
The sound level is roughly proportional to the power you put into it. This Tesla Coil produced a noise level akin to that of a blender (food processor).
direct tel number?
Attached is photo of my large Tesla coil.
D.C. Cox
Look at simple things like the Ionic Breeze from Sharper Image, Cell Phones, RF toys etc.. All were the brainchild of Tesla yet there were too many ideas too quickly to make any sort of profit from. Think of how big pharma operates now, they stockpile patents then release products creating a pipeline of viability for maximum profits. The FDA testing times vs. patent expirations defines their throughput. The "money changers" run the show and will only allow us to have what they think we are able to handle so that society does not buck their authority and control.
The only real protection you can have is not touching it. This gets difficult as when building it you would often run it and then make adjustments. You should make sure your capcitors have bleeder resistors so that they wont stay charged and physically disconnect the TC from mains before you go near it.
Proper grounding of various parts and controls is essential. If somehting fails it is possible for things to float at a very high voltage without you realising. You don't even have to touch and a spark can jump out and kill instantly.
If it is your 1st TC I really think you should not use MOT's. Use an NST as the current limiting helps keep it safer and is less likley to damage your components.
You shouldnt get near enough to need a faraday cage when it is running. THe age would also effect the tuning an operation of the coil.
The structure was shaped like a Christmas tree with a Van de Graaff generator at the top. Electrical arcs would travel up the structure and energize the generator, which launched powerful bolts of electricity for a considerable distance, potentially delivering 3 bolts of electricity with a single charge-up, depending on the number of enemies who were present in the area - obviously, additional charges would not be used on already destroyed enemies. Based on the unit's appearance, it seems as if the unit was acting as a giant staggered capacitor which is released by a maser-activated air ionizer, delivering power in massive surges to the generator ball at the top. Another Maser, more powerful, flash ionizes the air between the top collector and the target, and the simultaneous discharge travels through the air to the target, incinerating it. Tesla troopers who fired upon a Tesla coil would not damage it - instead, they would power it up, supercharging it under regular conditions and keeping it powered under low-power conditions. A supercharged Tesla coil had even greater range and power than a regular Tesla coil.
WILL THIS COMBINATION WORK IN REAL LIFE ?
------------/ HOW DOES THE MORAY GENERATOR WORK ? , IS IT SIMILAR OR BETTERTHAN COLONEL DR TOM BEARDEN'S M.E.G GNERATOR.
can an tesla coil attract lightning bolts ?
Anyone who wants to see a singing TC in action need only head over to Youtube.
People take apart an NST so that they can seperate the center tapping of the windings from the ground. This allows the full AC voltage to be used. Without doing this, you capacitors will only charge when connected between the ground and one of the output therefore giving only half the transformers voltage rating.
It is better to solder a bleeder resistor between the capacitor terminals. This would be a very high ohm resistor that would slowly discharge the capacitor.
Happy Birthday to Dr Tesla
The 2500pF is likely to be making your circuit have the correct resonant frequency. Tuning a small TC is often quite difficult.
It sounds to me like you are not getting enough feedback from your coil. You could have a too short antenna. Also, Check to make sure that your startup oscillator is at least running around 1/2 of the coils resonant frequency. The only other problem I could think of is if your voltage regulator has somehow failed.