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A DIY Tesla Coil
DC Powered with Plasma Output
The aim of this design was to get the highest voltage (or longest arcs) possible from a single self contained unit.
Check out the new 1kW Tesla Coil!
WARNING: High Voltage Device!
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).
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Input Voltage | 12 - 24V DC |
| Power Consumption | 250W Max | |
| Max Arc Length | 25cm | |
| Output Voltage (approx) | 250kV | |
| Primary Transformer | 2 x Car ignition coils in parallel - 20kV | |
| Capacitor | MMC 20kV | |
| Spark Gap | 5x 6mm pipes, Variable | |
| Primary Turns | 4.5 (Tuned) | |
| Secondary Turns | 850 | |
| Secondary Height | 40cm | |
| Secondary Width | 5cm | |
| Topload | 10cm Sphere | |
| Special Features |
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A pipe from a hole in the top of the sphere and down the inside of the secondary coil is used to supply gas to form a type of plasma electrode.
Using Butane gas and air, a blue flame can be used as an interesting discharge terminal. The heated CO2 emissions provide a low pressure channel to conduct the electricity more easily than air. This produces a large plasma column above the flame. At certain spark gap discharge rates the plasma column can be made to resemble a stable double helix formation. Small quantities of other gasses such as neon or helium can be mixed with the butane to produce slightly different colours and effects. The table below should help you find some of the components needed for this project.
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Component
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Max Voltage
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Source
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Ignition Coils
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~20kV
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Capacitor Bank
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20kV
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HV Diode
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30kV
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Power Transistor
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400V
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Neon / Helium
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n/a
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ST Gas
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Control Circuit
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n/a
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Capacitor Bank - The capacitor used in this project was made by combining a large number of lower valued capacitors. By connecting smaller capacitors in series the overall voltage they will tolerate is increased. To obtain a higher storage capacity (capacitance) the capacitors can be connected in parallel. This type of capacitor bank is known as an MMC (Multi Mini Capacitors). The next version of this project will use specially designed large pulse discharge capacitors. These capacitors can be more efficient than an MMC, but they can be expensive and hard to find. |
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Primary Transformer - Ignition coils (Induction coils) obtained from a scrap yard are used for this design. The old ignition coils provide a very cheap way of generating a high voltage for charging the capacitor. The voltage increase in an ignition coil is not determined by the turns ratio like in normal transformers. The secondary voltage depends upon the rate of change of the current in the primary coil. Older ignition coils such as ones from a scrap yard may not work as well as new ones. Over time the insulating oil inside the casing becomes less effective and can lead to internal arcing. This can damage the transistors and the control circuit, rendering them useless |
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Control Circuit - The control circuit is based on a simple oscillator provided by an NE555 timer chip. The square wave pulses are sent to a set of four 2N3055 power transistors mounted on a large heat sink. These transistors can switch a good amount of power quite quickly, but they can be sensitive to voltage spikes caused by feedback in the circuit, or faulty ignition coils. The Ignition coil driver circuit shown below shows how the signal from the 555 chip is pre-amplified, so that the large transistor array can be driven effectively. Using 2N3055 transistors in this way is not ideal, but it is what we had available at the time for the project. Modern IGBT transistors are much more effective and less prone to failure from voltage spikes. |
The output from the ignition coils is rectified (converted to DC using diodes) so that can charge the capacitor bank C1 shown b elow.
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Coils - The primary coil is simply made from 2mm enameled copper wire, wound around a plastic stand. There are six turns in total, but the connection is made at about 4.5 turns when tuned. The secondary coil is wound from 0.4mm enameled copper wire around a plastic drainage pipe. Safety - Attached to the capacitor is a short circuit switch that is activated by a long plastic handle. This is used to make sure the capacitor is fully discharged, and cannot recharge whilst making any manual adjustments. There is also a switch to isolate power from the ignition coils that is activated using a insulating pull cord. |
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Special Features - This project has several extra features compared to a common Tesla Coil. The topload sphere has a small hole to allow gas to be emitted. A 5mm plastic pipe runs down the inside of the secondary coil, and out of the plastic base. This allows the gas to be piped in, without interfering with the normal operation of the Tesla Coil. |
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Future Developments - This project is currently being upgraded. The new design aims to achieve a higher power throughput. By using more ignition coils in parallel it should be possible to increase the size of the spark gap, or to fire it more rapidly. New ignition coils will used instead of the second hand ones for improved stability. The new design also incorporates voltage and power monitoring features. It also has a neat metal finish and multiple outputs so that it can be used as a multi purpose portable high voltage power supply |
The information provided here can not be guaranteed as accurate or correct. Always check with an alternate source before following any suggestions made here.
Thank you for reply and sorry here is an other question: what is a maxim. length of sparks ?
Arc welders use a low voltage output so that you only get high current when it strikes low resistance materials like metal. Using ohms law you can see that there is not enough voltage to cause a large current to flow in a person.
A MOT is a super dangerous transformer. It puts out around 2kV and is able to deliver a lot of current. Don't use them.
Thanks again,
Stephen
On the Tesla Coil Page you can find a diagram of how the coils and capcitors are connected, and a description of how the system works.
The primary coil is usualy a flat or conical coil with widley spaced windings like the one shown on this page. The centre of this coil is where the secondary coil is placed.
The secondary coil is wound around a plastic tube. It uses thin enamel coated wire (aka magnet wire) wound tightly for hundreds of turns down the length of the tube.
The 555 timer is used in the circuit for making a high voltage DC supply to power the tesla coil from batteries. You can see schemaitcs for the 555 circuits on the PWM Signal Generator page. This 555 circuit is used to drive transformers for stepping up the battery voltage to one high enough for the spark gap to work. You can see circuits for that on the Pulse Controler page, the Power pulse genrator page, and the ignition coil driver page.
The tank capacitor in this coil was 15nF @ 20kV which was made by linking smaller capactors together. You can see the electonics section to learn about connecting capacitors together.
The length of wire needed depends upon all the other components used to make the tesla coil. It is usually several hundred turns.
The inductance of the coils simply determines the frequncy at which they will resonate.
e.g. A large inductance in parallel with a small capacitor (secondary coil and top sphere) will have the same resonant frequency as a small inductance in parallel with a large capacitor (primary coil and MMC or pulse capacitor)
I had put this project on hold Several weeks ago due to a fairly heavy cold, an email asking for advice with another coil awoke my interest in a 12 volt system again.
I have mounted 7x2n3055`s onto a heatsink that was given to me ( overkill but, it was free ).. Now i need to connect to a signal generator.
I made the Power pulser from this website which works very well.
Is there a simple way to drive the 2N3055`s with that circuit.
Using my 3inch coil powered from the pulser I am able to draw a spark of about 25mm, in low light the corona is visible at the top of the coil.
1. How can you calculate/measure the output characteristics of an ignition coil esp. it's current and voltage. I have estimated my single ignition coil puts out about 15kv using spark length as a rough guide. And, using the transformer equation calculated the current was a tiny 0.5mA. Do you know a better way to ascertain the current output?
Is the high voltage output of the coils rectified using a string of high voltage diodes, if so how should they be connected to the circuit, which way round the cathode/anode etc?
Is it necessary for the output to be rectified before applying to the tank capacitor (MMC)I dont really know.
The current can be calculated in a similar way. If the HV output is shorted with a low ohm, high power resistor, the small voltage measured between its terminals can be used with ohms law to calculate the current flow.
The HV output from the ignition coils in this example was rectified with a full bridge rectifier arangement of HV diodes. You can see how they were connected on the Power Pulse Generator page.
When using ignition coils it is most effective to fully rectify the output. This is because the output is pulsed and more +ve than -ve. Mains powered Tesla Coils use proper AC which has enough current to charge the tank capacitor on each half cycle (e.g. UK Mais frequency = 50Hz, Cap gets charged 100 times per second but with alternating polarity.)
This uses a spark gap made from a few sections of brass tube.
The breakdown voltage of air is often stated as around 10kV/cm. This is a rough value because the density, humidity, etc vary and can effect the outcome. The value given refers to the elctric field in a reigion of space rather than the voltage between two terminals.
1) Is there any reason why you chose Butane for the gas? Are there any other gases that would also create effects?
2) How long would one of these as built on this site run on 1 battery?
2)Depends upon the battery size!:) It can draw aroun 5A @ 12V so if the SLA battery was like this one (7Ah) it would last about 40 mins non stop.
would the primary coil have to have the same electrical resistance as the secondary ? by this i mean secondary windings = more resistance . is this why there is lesser primary widings?
the copper i have is 'secondary windings'= 0.5mm 2000 windings and the primary = 1 mm 5 windings
and would the frequency of ossilations matter
You could try diferent numbers of turns, or different sized capacitors in the primary circuit. Try starting with a larger number of primary turns (maybe 20), then reduce by 1 turn at a time untill you see some results.
This still may not work if your frequencys are really far off. You could try using the Tesla Coil Tuner to match your circuits.
1 would a tv fly back circuit be suitable for the power source or enven a ignition coil?
2for tuning frequency of ossilations would a series of capcitors be better or different size compacitors?
3 can the compacitor be dialetric or a laten jar design?
and last but the least is your circuit diagram at the top for protecting spikes in ossilations rather than the frequency circuit its self?
The simplest way for adjusting the capacitance is to just buy/make several capacitors that are rated for the correct voltage, then connect them in parralel. You can then add or remove a capacitor to adjust the capacitance. You will probably still need to move the clip on the primary coil to get fine tuning. The caps can be any type as long as they can withstand the voltage they will be exposed to. Use thick wire between the capacitor, spark gap, and primary coil for better efficiency.
The circuit diagram on this page is just a simple ignition coil driver with no spike protection. The ignition coil driver is used to charge the primary tank capacitor.
This thread in our forum may be useful. Unfortunatley the forum is closed for new members now because of constant spam. It may get removed alltogether.
thanks for helping when i get it working ill post on my web page
I'm not too sure about microwave oven caps. If they can handle the voltage then I assume they will be ok. It may be easier to use several smaller ones so you can make smaller adjustments.
Yes you can twist wires together to increase the current handling capacity.
and i came up with a cleva idea for a spark gap i have two screws mounted over a cooling fan but the screws are tied on copper which was wraped around a pen to get a coil.
I'm not quite sure how you have made your secondary, but I think thousands of turns may be too many. There was around 850 in this coil, and I have also been able to to drive coils about half that size without changing any other components.
All circuits will have some resistance, capacitance and inductance, deliberate or not. It is often labled as 'parasitic' if it is not deliberate. For a Tesla Coil most consideration is given to the inductance and capacitance values. In the primary circuit, thick wires are used so that the resistance of these does not reduce the current flow. In the secondary coil a long thin wire is used, so the resistance is much higher, but this resistance is not very significant in comparison to the reactance.
The resonant frequency of a TC is determined by the product or inductance, resistance, and capacitance (LRC). Both the inductance (L) and the capcitance (C) are 'storage vessels' for energy. The capacitance stores energy in an electric field, while the inductance stores energy in a magnetic field.
When the spark gap first fires, the energy in the primary capacitor is dumped into the primary coil which stores the energy in a magnetic field. When the capacitor is empty, the current will stop flowing, causing the magnetic field to collapse. As it collapses a current is induced back into the coil (in the other direction) which then charges the capacitor again.
The time taken for this cycle is calculated from the LRC values, but we can ignore R because it is very small. Bigger values for L and C mean it takes longer for the energy to move around, therfore resonating at a lower frequency.
The secondary coil also takes some of the energy from the magnetic field collapsing around the primary coil. This larger coil has a much higher inductance (L) and it also has a small amount of parasitic / self capacitance (C). Again the resonant frequency of this coil is a product of LRC. In the secondary, L is large and C is small, but in the primary, L is small and C is large.
If the frequencies of the two LRC circuits match, then energy can be effectivley transfered between the two. The initial store of energy is in the large primary capacitor, but we are transfering this energy into the tiny self capcitance of the secondary coil and its sphere. For the laws of conservation of energy to hold true, the voltge in this smaller capacitance has to be proportionaly higher.
This probably all sounds complex, but you can get a TC to work without calculating all these factors as long as you are able to tune part of it. The LRC and frequency of the secondary coil are pretty much fixed, so it is common to tune the primary circuit to match this. Increasing L, R or C will decrease the frequency of that circuit.
I haven't a very good understanding of capacitors so I'll ask. Is there any way that you could provide me with a diagram or schematic of how you built your MMC. If not, could you tell me what capacitors you used
If you want your MMC to be rated for 5kV for example, you would need to connect 10 of your 500V caps in series.
The two remaining teminals at the end of this string of capacitors make the new terminals for A 5Kv capacitor.
When the caps are places in series, it reduces the overall capacitance. To get around this you make lots of strings of capacitors then connect these in parralel.
The diagram shows strings of 10 caps in series, and 3 of these in parralel.
In addition to possible damage to mains from high voltage discharge, Tesla coils radiate over much of the radio spectrum and may play hob with low power systems.
EMI filters are a good idea, but may be sacrificed to a direct hit.
the space of spark gap become shorter and make the arc become smaller.if i can make a longer space of spark gap,does it give bigger output(arc)? also what is it possible to touch the arc with our finger?
cause i have seen this on the Guinnes world record it's so amazing can generate arc from the tongue.
I can't really understand what you are describing, but I'll make a guess.
If the voltage rating of you capacitor is larger than the voltage you are charging it with, then it is not likley to explode. It would only overheat if you over powered it significantly.
The energy stored in a capacitor is proportional to the voltage squared (E = 1/2 C V2)
Increasing the size of your spark gap will means it will fire at a higher voltage and therfore dump much more energy into your coil on each pulse.
You will need to find a compromise between spark gap voltage and firing rate. This is because a faster firing rate allows the sparks (on the output of the tesla coil) to re-use the channel of ionized air left behind by the previous spark and therefore grow longer over a series of cycles.
Daniel:
Even battery powered Tesla coils are very dangerous and can kill instantly. All tesla coil construction and operation should be supervised by a responsible adult. There is more information about powering a TC from ignition coils on the power pulse generator page, or visit the page with the tesla coil theory.
A single HV diode would be enough to alllow the cap to hold its charge. A full rectifier arrangement will only give a small boost in voltage compared to the single diode.
I couldn't possibly suggest that it is safe to touch any high voltage device (except maybe a small VDG). There is wide belief that the skin effect will prevent the dangerous currents entering the body, but this not exactly true. The conductivity of the body is quite varied and there are often low frequency components in the Tesla coil output.
I have had the occasional accidental zap from the top of this TC, but it does not feel healthy :). I certainly wouldn't do it deliberatley. About halfway down this page is a table showing the levels of current needed to cause fibrilation and other effects.
It basically involves charging up a capacitor then dumping the energy into a high ratio transformer to get a pulse of high voltage with low current. A page called explore a stun gun shows you the basics.
With my battery powered tesla coil, just a few turns out on the primary coil would make the difference between 1cm and 20cm sparks. Here are a few tips that may help you in the process.
Reducing Losses
Connecting wires in the primary circuit (between spark gap, capacitor, and primary coil) should be as short as possible and using thick wire. This helps reduce lost energy due to current heating in the wires.
All HV interconnecting wires should be well insulated and kept away from eachother. Avoid trailing wires accross surfaces such as a wooden base too. This helps reduce losses from capacitave coupling and eddy currents.
Using a transistor to switch the ignition coil, could also be adding resistance to the circuit. You could add more identical transistors in parralel so that more current can be pulsed through the coil.
Use a seperate ground connection for the base of your secondary coil. Using thick wire connect it to a good ground source such as a long copper pipe hammered into the ground
Tuning
It is important that all the parts in a tesla coil are resonating at the same frequency, otherwise power is not effectivley transfered.
The secondary coil is pretty much set in its resonant frequency, but small adjustments can be made by altering the size of the topload (torroid or sphere). Increasing the size of the topload will reduce the resonant frequency of the secondary coil (think about a bigger sphere means it takes more time to 'fill' with charge). It will also mean that sparks will not jump out on their own as easily, but they will be bigger when they do.
Tuning the primary curcuit is achived by altering the capacitance of the tank cap, or adjusting the number of turns in the primary circuit. The easiest way is usualy to adjust the number of turns, but this can also be tricky if your wire is insulated.
The simplest way (without any extra equipment) to make sure your primary and secondary circuits are resonating is to operate your TC using different primary coils, then look how long your output arcs are. Start off with one turn, then increase by one full turn each time you try it out. If you see a rise in the output, make a note of the turn number, but keep going as there are often multiple points of harmonic resonance.
When you are satisfied you have found the best turn number, you should fine tune it bu making smaller adjustments. A quater to an eighth of a turn is about a small as will be noticable on the output. This method involves repeatedly firing up the coil and then adjusting the the HV circuit. It is very imprtant that you isolate all power, and discharge the capacitor before making any adjustments.
A safer method is to tune the circuits with a low voltage. This can be done by using a simple device known as a Tesla Coil Tuner. This device will find the resonant frequencies of your components and allow you to adjust them so that they match, but without using any dangerous high voltage.
If using a variable frequncy HV supply, then this can also be adjusted when you adjust your spark gap size. This is to make the incoming HV pulses match up with the charging and discharging of your capacitor bank.
Also a full bridge rectifier like shown on the power pulse generator circuit diagram, will mean you get twice the number of DC pulses, therfore increasing the overall power throughput.
Placing a snubber (such as a capacitor and resistor in series) in parralel with the coils input terminals will help. You will need to experiment with the values of capacitance you need. The snubber will absorb some of the energy so that the circuit is protected but there will be a small reduction in the output voltage.
how to increase the output voltage for this tesla coil?
to RMCybernetics: also,question about MMC cap size) what is it? )
artemon: See post 832 and replies for some more MMC info
mad scientist: The flyback transformers in a CRT have a built in rectifier so that the output is already DC. This should be able to handle about the same sort of power as a single ignition coil.
800 or so turns is pretty typical for a TC secondary coil. 2-3k would be too many for a couple of reasons. The inductance and self capacitance will be very large and therefore give the coil a very low resonant frequency. Your MMC or primary coil would need to be very large to match the frequency. The other reason is that the long thin wire will have a large resistance therefore lowering the Q factor of the coil.
You will need to rectify the output of the ignition coils to charge the MMC. A single high voltage diode between the coil output and the MMC would do it. The anode of the diode (the end with a stripe) would be connected to the MMC. I would recommend placing a choke (an inductor) between the diode and MMC to help protect the diode from surges.
The base of the secondary coil should be connected to the ground for it to resonate properly. The ground connection used sould not be the same as the rest of the circuit. You need a dedicated RF ground such as a metal rod in the earth.
Secondary Coil:- 950 turns on 2 inch cardboard tube.About 5 coats of Varnish.
Spark Gap:- Static, 2*10mm bolts.
Capacitor:- 1 wine bottle filled with salt solution and covered with foil ( value unkown ).
Power:- 2 ignition coils ( not matched pair ).
oops nearly forgot :-4k7 Capacitor across the load.
A solid state tesla coil (SSTC) uses a solid state device such as a transistor instead of a spark gap. Unfortunatley it is not as simple as just replacing the spark gap as there are alls sorts of things needed to make it all work well. They are expensive and difficult to make. They are also easy to break if they are not made well enough.
You can't connect them in series.
2nd: 10M resistor across each diode will conduct pulse back,so diode will be useless...or i'm wrong?
The only alternative is to use proper high voltage diodes. There's usually plenty on eBay.
1. Over voltage. It's quite possible that you are getting more than 21 kV from you coil. If your spark gap is smaller then the cap will discharge before it reaches a higher voltage. As I mentioned before, the cap should be rated for about 2x the voltage you intend to charge it to.
2. Over current. The capacitors you used may not be able to handle the large current pulse caused when rapidly discharged.
3. Internal mechanical failiure. When a cap is charged, the internal plates are strongly attacted to eachother. When they are suddenly discharged the force is released which causes a shockwave in the caps. This can cause some caps to fail but it is usually after many cycles.
Question: what's the difference between ~8nF mmc or ~18nF? (i know that changes resonant frequency,but what else changes? performace changes?longer time to recharge?) thanks. and sorry for that amount of questions(
The capacitance of a capacitor is a measure of how much energy it can store for a given voltage. 18nF is 2.25x the 8nF capcitor so it will hold 2.25x the energy when charge to the same voltage. Imagine it as a container with a size measured in farads. A bigger container will hold more but it will take longer to fill and longer to empty.
The number you use just depends on how much current you want to switch. Each 2n3055 will handle a maximum of 15A.
The wire you need depends on eveything else you use (size of topload, primary inductance, primary capacitance). You must calculate this yourself.
Flyback transformers are usually designed to work at high frequencies.
Was it your diode string or did you find some other problem that you fixed to get it working?
The most common primary coil is a flat spiral for spark gap Tesla coils because it concentrates the magnetic flux at the base of the secondary coil and allows for loose coupling to prevent flashover. Some people use a conical one to increasec coupling slightly but it makes only a little difference in practice.
For very small tesla coils such as single or dual ignition coil driven types it is sometimes possible to use much tighter coupling. Wrapping the base of the secondary with several layers of insulation and then wrapping a primary coil onto that can provide a large amount of coupling for situations where the output power is not too great.
mad scientist:
Transformers, motors, or the ballasts from inside flourescent light fittings are typical sources of enamled wire.
Your transformer should be earthed, but Tesla coils are just not safe and should never be touched when active.
A very rough estimate for output voltage is for each mm of spark there is 1kV. This applies for a spark between two smooth round electrodes. The spark will jump further between wire tips because of the higher concentration of electic field.
Small ones can often be found on ebay for about £30 + shipping.
It's difficult to say if this would improve your power output. Making the coil shorter and wider may improve the coupling but it could increase the losses in the system due to corona discharge or capacitive coupling to ground.
If you have the time and materials it may be worth trying a few different versions of your secondary coil to help you learn how changing different parameters will effect the system.
There is a version of this driver circuit which uses a MOSFET. It is avalable as a power pulse modulator or the DIY pulse controller
I am a high schooler who has had a long time fascination with electronics, esp. high voltage.In one of my attempts to amuse myself with metal etching, I constructed an arc welder USING A MW TRANSFORMER! Please, Please don't risk injuring yourself. My blog is caringbridge.com/visit/iandaniher
I wound up in Shriner's Burn Hospital for THREE MONTHS! Please email me at explodingmind@gmail.com with any questions.
Although the can picture is pretty sweet...
The current depends on the size of the transformer. It could be anything. A higher firing rate for a spark gap Tesla coil will give longer output arcs.
Thanks for sharing your story DyD. For those who don't know, an MW transformer is the transformer from a microwave oven. These things will deliver lethal electric current in an instant. Don't mess with them.
MOT's are dangerous because they have a low impedance which allows them to put out a large amount of power. The impedance is what limits the current drawn from the power supply (the mains in most cases)
If you run your MOT from your power pack, the current will already be limited to 3A because of the impedance (or overload protection) of the power pack its self. The low input voltage (4V) will also prevent any large currents from flowing. The MOT is designed for a mains input of 240V (UK) and gives an output of a few kV. This is only a small step up ratio of about 10x the input voltage. So if you use an input of 4V you are only likely to get about 40V out.
Personally I would just completely avoid using an MOT and stick to high ratio coils like ignition coils. They are safer, but you should still be very careful as no DIY high voltage device should ever be considered safe. Also if you are charging capacitors, the danger is hugely magnified because they can store a lethal energy jolt that can be delivered in an instant.
Dan:
The current you get depends on a lot of things like input power, frequency and pulse width. It also varies between the different coil types or models.
You can measure the current using a standard voltmeter and a low resistance (1 ohm or less) power resistor.
If you place the resistor between the output and ground it will be almost shorting your coil and therefore drawing lots of current. If you measure the voltage across the resistor you can then use ohms law to calculate the current flowing through it. (I = V / R)
I want to know that the simple coil prepared is hazardous for a person? what if someone got in contact to discharge from the coil? n can some one use a 12/ 24 adapter instead of a battery?
There is still a lethal level of current flowing in the primary circuit though. Touching this would likely result in serious injury or death.
A mains adapter is not likely to be able to provide enough power (unless it's a real expensive one) and it may be susceptible to damage from RF as well as allowing RF to get on your mains line and damage your household electrical items.
how have u created the capacitor bank provided logical diagram n reality has lot differences
how to connect the coil
seems like i m going to need a complete diagram
n the cheaper, smaller n safer version of the TC will have same beautiful arcs
What gap do you have? About 5mm should do it. If your cpacitor is only small (< 10nF) then it should charge quickly, so if it's not, your HV supply may not be delivering enough current.
Our Power Pulse Modulator makes a great flyback driver. It is similar to this circuit, but with added features such as inductive spike protection, back EMF and power monitoring, and built in cooling.
Generally the frequency of a TC output is too high and the current is too low for use as a power supply like this.
Some people consider the car ignition coil and flyback transformers as Tesla coils with solid ferromagnetic cores. Either of these will work like shown on this page.
Another version is the Tesla magnifier which is a standard (air cored) TC with an extra coil simply connected to the output.
A MOSFET would work as long as its rated for enough current. You will also need to use a higher gate (base for NPN) voltage and make sure there is a resistor from gate to ground. This is important for switching the transistor off as quickly as possible.
I've never used a magneto, so I couldn't say.
will:
Check the lower end of the coil is connected to a good ground (like a metal rod in the earth.
Check the coupling is not so close that plasma is forming between the primary and secondary coils at the closest point.
If they are ok then I would guess that it is not in tune. The primary circuit must be adjusted so that its resonant frequency exactly matches that of the secondary coil with topload. The most common way to do this is to adjust the number of primary turns by tapping off at different points. More turns = lower frequency
Bigger capacitor = lower frequency
Bigger Topload = lower frequency
I've read that neon sign xfmrs are often used for tesla coils that size, but i just can't get my hands on ANY!!! any other suggestions?
Thanx a lot!!!
--nino-de-voltaje
I would love to be able to buy stuff on ebay, but i'm "underage". i'm not 18.
a couple of days ago i tried ebay, but they wouldn't allow me to register because i am under 18.
Another question: What ignition coil/tesla coil circuit should i use for a tesla coil only 4 inches high?
here is a picture of it.
If you are replacing a transistor in the same position in your array than there must be something wrong with either the wiring of the circuit or the other transistors.
If it's heating up and eventually blowing, this is due to it switching power beyond its ratings. This would lead me to believe that the other transistors are either faulty not switching on for some reason.
You can test a 2n3055 by replacing your ignition coil with a load that will give you an idea of current flow such as a motor or light bulb. The faster/brighter it is the more current is flowing.
Remove the signal source from the base pins of the transistors and make sure all transistors are separated from each other. Now connect the signal or a DC voltage to the base pin of the 2n3055 under test and take note of the power level shown my your load. Test each 2n3055 like this to see if there are any major differences. Compare results to a new transistor so you can tell if they are performing correctly.
der Strom,
The rectified output of a single ignition coil driven by a 12V pulse modulation circuit is likley to be enough power for charging the tank capacitor of such a small TC. You should refer to the DIY Plasma gun page for details of building a tiny Tesla coil.
by the way, i built a simple driver circuit for the ignition coil. it plugs into 120v AC from the wall, and it has a dimmer switch so the coil does'n get fried. is it possible, or safe, to use power that is directly plugged into the wall for my mini tesla coil? or will the "backflow" ruin the power supply?
Again, thanx a lot!
120V @ 50Hz would cause too much current to flow in the ignition coil. This would cause it to burn out.
Mains powered Tesla coils often use a neon sign transformer as it can be powered from mains voltage.
It's probably best to make some sort of MMC or have a selection of different sized caps to try. With an MMC you can add/remove a cap to increase/decrease the frequency as needed. The cap used in the plasma gun was just 2nF made from two 1nF ceramic disc caps in parallel. The optimum value was found by using an MMC of much smaller valued caps and adjusting it as described above.
Also, I have never seen a cap rated for nF. I have only seen them in uF and F. could u send a pic or something?
Thanks very much for all of your answers!!!
If the caps you have are of similar physical size, the HV ones are likely to have a much lower capacitance. Most capacitors rated in the kV range will be much smaller than F or uF unless they are physically quite large. This image show some typical HV ceramic capacitors and some HV diodes) The left most caps are rated for 1kV and 4.7nF.
I'm not sure about Radio Shack stores as we don't have those in the UK. If it is the same as RS, then you may be able to find some there.
Look up information about a 'Faraday Cage' works for info on shielding EM interference.
Claydough,
There is not much info because they are simply a single piece of metal (or several joined to make one).
Imagine the metal as a reservoir for 'electrical water'. You connect this to one end of a hose (your secondary coil) to allow it to be filled and emptied while the current flows back and forth in the coil. The opposite end of the coil is connected to the ground (literally) which supply's all the 'water'. The 'water' is pumped up and down the secondary coil with the magnetic fields produced by the primary circuit.
I would now assume that the diode you do have is damaged and will probably allow current to flow in both directions.
You might be able to get away with connecting lots of lower voltage diodes in series, but this method can cause diode failiure.
You are charging your low voltage caps because the small gap you leave breaks the connection to your coil just in time for some of the charge to remain.
Also, any chance of you turning up at the Cambrige Teslathon with your mini tesla and latest tesla project...It's at the Cambridge Museum of industrial technology on w/e of 27-28th of October...I'm sure your gas plasma tesla coil would generate alot of interest! hope you and your team can make it.
The magnetic field is pretty well conntained within the case but you certainly should see some deflection of the compass if it close enough.
Making sparks broadcasts a wide spectrum of RF noise which will intefere with many appliences. Most modern exipment has some sort of filter to tr to reduce interference problems.
crisH,
You can get a rough idea of the pinout by measuring the resistance between the pins and drawing a diagram as you go. The one in our surplus store was tested with our PWM-OC10A by just trying combinations of pins and measuring the corresponding output voltage. Two of the pins (I can't remember which) had a low impedance and gave a steady 20kV output.
Yes a few of us should be visiting the Teslathon. I'll bring the plasma gun too. See you there.
You can also connect the MOSFETs in parallel.
Common mains driven TCs use sine wave driven transformers with a low frequency (50 - 60 Hz). This allows the tank capacitor to charge in 1/4 of a cycle and therefore fire many times per second. The voltage change in these types of transformers is proportional to the difference in turns on the primary and secondary sides.
The voltage rise in an ignition coil is a proportional to dI/dt (the rate of change of current). The square wave driver gives a HV output made from high frequency pulses which are too quick to charge the tank capacitor fully on each cycle. The diode serves to keep the pulses unidirectional and to stop the capacitor discharging back into the ignition coil.
sincerly machine of pure excellance.
Some more items have been added today.
Here's the circuit I had tried (just the coils):
In parallel sparks will look the same, but you will be able to draw out arcs further than you would with a single coil. The will still only jump the same distance.
In anti-parallel the sparks will jump further due to increased voltage. Arcs should also be larger than a single coil.
For this circuit, would it be possible to use a 12v wall adapter to run this coil instead of a 12-24 volt battery, as long as I don't use it to run a Tesla Coil?
I'm sorry for all of the questions, but I am still trying to learn more about high voltage electronics.
I don't mind the questions, I just want you to learn the science involved and not just try to copy diagrams.
I built the PWM and am using it with 3 ign coils. It charges a .19uF HV cap. This cap is discharges to ground via a spark gap.
If we look at the 'scope and analyse the actual arc discharge it oscillates. How can I prevent this "ringing" ie. I want to control the length of the arc dicharge sothat each discharge is unidirectional. Tesla stresses this in much of his writing on radiant energy.
Any ideas to help? Thanks
Devn
The 358 should work ok. Check the pinout on the datasheets so you can make sure you use the correct pins.
Devn,
The ringing effects is caused by a combination of capacitance and inductance. Even a small amount of stray/parasitic inductance will cause this. When the cap discharges, the flow of current stores some of the capacitors energy in a magnetic field. As the cap discharges, the magnetic field collapses and induces a current back into the circuit in the opposite direction. This process can repeat many times over during just a single spark which is what gives you the AC type waveform you see.
A diode placed in series with your spark gap would stop most of the ringing, but finding a diode that can withstand the large current pulse and high reverse voltage could be expensive.
Another option is to try to extinguish the spark before the voltage has time to reverse. This may be difficult in practice as the timing would need to be quite precise. Improved quenching can be achieved through the use of a rotary spark gap, air pressure, permanent magnets, or some other mechanical means. A large magnet placed either side of the spark at 90 degrees to the flow of current will cause the arc to immediately deflect when it forms. If the deflection is enough, it will stretch the arc to the point where it is extinguished.
To get a truly unidirectional pulse will be very difficult indeed because all the components will have some stray inductance and capacitance. Improved spark gap quenching will certainly help though.
More 2n3055s are used when driving more coils together to handle the power.
Awsome High Voltage,
Are you using a HV diode between HV output and capacitor?
http://www.uoguelph.ca/~antoon/circ/hv/ss-tesla/ss-tesla.html
I have nearly finished it but am thinking ahead to getting it to "sing" via some sort of MIDI control. Would this involve a MIDI to CV converter to change the frequency of the pulse generator coming from the 555 chip or is it not that simple?
Also what is the best style of HV capacitor to start with (as you can see i need a 1500pF rated at 10KV) I was thinking of a simple glass plate with Aluminium foil but some of the beer/wine bottle versions you have look slightly easier.
Thanks in advance
Simon
A singing arc is usualy produced by amplitude modulation (AM) of the output. This will be tricky with a spark gap coil because the firing rate is not well defined. You could AM the signal from the 555 so that the ignition coil output varies with the input sound. This would alter the firing rate of the spark gap when the sound alters, but I doubt it would be sufficient to make any sort of quality sound, if even recognisable at all.
Proper HV caps or an MMC are best, but as you can see from Santas TC, the foil and bottle method works well.
thanks again in advance
Simon
The second figure on that site IS a sstc--and run using a 555 timer and no spark gap (as far as I can see). I think you may have seen Fig. 1 istead of Fig. 2.
If i'm wrong, I apoligize for the inconvenience.
Making the arc from the your ignition coil sing would not be to difficult. See the comments on the ignition coil driver page.
Theoretically you just need to replace the spark gap with a solid state device and have another signal (or feedback) to switch this on and off. Unfortunatley the practical application of high voltage, high current, high frequency switching is not so simple. For a true SSTC you will need a lot more cash to spend and a totally different design. Google SSTC for some shematics and examples.
der strom,
Nope, there is definatley a spark gap shown on figure 1 and figure 2.
Thanks again for all your help you guys run one of the best websites I have found just because of the comments section on everything and you quick and informed responses. thanks
Simon
The sine gen would need to an AC source of power and not just a signal source. Multiplier circuits are also not very efficient, so stepping up from 3.5V will waste a lot of energy. Your MOV would need to be big and very fast acting. They are not really meant for use like that so I think it would stop working after a while. Its a good idea and shows you are understanding the principles but I think the practical application of it would be difficult.
der strom,
The last paragraph on that diagram says "This SSTC diagram is over simplified. The design in the SSTC-1 uses an H-bridge and an antenna feedback system."
The diagram is just used to explain the difference between an SSTC and an SGTC. It is not a functional circuit. It does also represent quite well the ignition coil driver, but without the signal generator.
Simon Dodd,
Yes, the transistors that would replace the spark gap would be activated by your audio signal. Changing an SGTC into an SSTC is not as simple as it might sound. The transistors in an SSCT typically only switch hundreds of volts. Switching kilovolts with a solid state device will be expensive and difficult. If you build an SSTC you will need a totally different circuit.
not confusing with "3 phase powered" types, where 3 phase is used to power a single coil.
Im talking about setting up a master 3 phase oscilator, then a power switching stage, (igbt or mosfet) and create 3 identical secondaires and primary coils and feed them with 3 phase power....
I can emagine the arcs would rotate and probaly form some kind of vortex.. the voltage feild would probaly be quite interesting too.
maybe the basis for some type of lightning sheild maybe lol
i can emagine the only complication could be creating 3 identical secondaries at the same resonant frequency.
I have a bit of a noob question:
music with one of these, will it work if I can get the hookup right? (I plan on working with a fiber-optic system for the musical piece so it doesn't fry/it doesn't fry me. of course, if anyone has a better and easier suggestion for that, I'm all ears :D)
The rate at which it fires must be greater than or equal to the nyquist frequency of your audio for it to be reproduced with any accuracy.
The simplest way to modulate an arc would be to just use an arc from an ignition coil.
can that be used with a tesla magnifier???
so the toroid is the only thing i need
and i got an ignition coil from a junkyard yesterday, but i dont have the resistors because OHMS is closed an i cant find any place to buy some
could you send me the full diagram of the ignition coil driver with the 555 timer and 2n3055 that doesnt use resistors
this is my diagram
:http://www.geocities.com/CapeCanaveral/Lab/5322/coildrv.htm
WOULD THIS PRODUCE MORE THAN 2 MILLION VOLTS about 1 billion volts and above??
enought for powering the flouruscent bulb of a whole town then i will go to the guinest world record
WARNING::: I AM JUST 11 YeARS OLD!!!!!!!
XD
http://www.geocities.com/capecanaveral/lab/5322/coildrv.htm
i think its the same as yours
only the BFY51 is changed
I just reposted this (being sure that you will answer this) by the way i love your website thinking of building a wbsite like this XD
I WORSHIP YOU
MY HIGHNESS
XD
PLEASE!!!
You could use leyden jars, but you must construct them well if they are to withstand 10kW.
The noncanister types have the terminals further away from the HV out terminal reducung arcing when running the coils at High Voltages.
Yes you can use these types. Our surplus coils are resin filled and have the inputs at the opposite end of the coil.
The advantage of oil filled types is that the dielectric essentially self healing in the event of a brief internal arc. Internal arcing in a solid coil will probably result in permanent damage.
Sars,
We don't generally make Tesla coils for sale because the insurance costs for such devices make it very expensive for small order quantities.
1. In the attached circuit which works very well with two ignition coils connected in antiparallel fashon, should I put a resistor from the gate of the Mosfet to ground?
2. Which works better for joining ignition coils, parallel or antiparallel configuration. In your circuit they appear to be parallel and in the attached circuit they are antiparallel.
Thanks for the help
1. You say it works well so I would say If it aint broke, don't fix it.
2. It just depends if you want more voltage or more current. In parallel you get more current so the tank capacitor will charge faster therefore giving a higher spark rate (bps). In antiparallel you get more voltage. The energy stored in a capacitor is proportional to CV2 so you will get significantly more power in each firing of the spark gap but it will fire less often.
I chose parallel because my MMC was only rated for 20kV and I wanted the bps to be high so the TC output was smoother arcs as opposed to jagged sparks.
We don't generally make Tesla coils for sale because the insurance costs for such devices make it very expensive for small order quantities. "
all you need is a disclaimer like this site that sells tesla's
http://www.amazing1.com/
http://www.amazing1.com/tesla.htm
Also, you guys at rm cybernetics should join the Tesla Coil ring web "club", it will reference people to your site the link to join http://www.webring.org/cgi-bin/webring?home;ring=TeslaRing
(it gives you a cool little applet for the bottom of your page!)
We were in the Tesla coil ring but we got kicked after we updated the site and forgot to tell them! Oops :)
The output of a flyback is not necessarily DC. The flyback you described has a built in diode rectifier as DC is needed for a CRT screen.
You would need to protect the internal diodes from over current and voltage spikes. The diodes are probably not rated for much current so you would need a resistor on the output. This should then be used to charge a large capacitor. Then from this capacitor you would charge your TC capacitor via an inductor. The inductor allows DC to flow through easily but prevents the high frequency of the TC getting back to your flyback. This method is used in the DIY Plasma Gun.
You could try connecting like you suggest, but this might destroy the diodes in your flyback.
Daniel Kuriloff,
Anti-parallel is where there are two outputs of opposite phase and therefore opposite polarity ant any one time. If you wanted to use four coils you would need to use two pairs of coils in anti-parallel. A pair being two coils in parallel. This would give you about 2x the voltage and 2x the current relative to a single coil.
For a Jacobs ladder it will work better with more current because this is what increases the plasma temperature and allows it to draw out further. The voltage of your power supply will just determine the size of the gap where the arc restarts.
from that diy tesla coil.
Oh and im sorry if my english aren`t wery good because i speak Finland.
Both. Use an EMI filter between the mains supply and the NST to protect your mains ring from radio frequency interference. You can also place RF chokes on the output of the NST if you want to stop RF getting to the NST. Use a saftey gap to prevent overvoltage where needed.
Markku,
40mm diameter
Space between turns: <10mm. Maybe 8mm
Angle from ground plane: <45°. Maybe 35-40°
The angle is actually not very important. It has only a minor effect on coupling vs. just a flat coil.
2) Can I connect 10W audio amplifier output to emitter and base of 2n3055 to make my TC play music?
3) Can you post how to use mosfet
instead 2n3055 (circuit)?
Many thanks and Happy New Year!
2) No, Not directly.
3) This circuit
Happy New Year
Please choose a name and stick to it for your posts on this site. I makes it much easier for me to answer your questions.
Should I use 1W resistors?
Thank you very much, you really helped me.
Now I can get working.
If you put 100kV across a resistance of 100k ohms the current would be 1 amp. There is no way your coil will output 1 amp at 100kV. This low resistance will effectively short the output of the coil causing its output voltage to drop considerably. To get an accurate measure of its voltage you would need have as little current as possible going through the resistors. A typical value would be in the 100's of mega ohms.
A resistor, capacitor or both will actually cause a voltage drop therfore reducing the voltage. I'm not sure where your misunderstanding came from.
Thank you for your info!
thanks again.
For those want to build one, you should visit Steve Ward's and Richie Burnet's site for both theory and practice.
http://www.stevehv.4hv.org/
http://www.richieburnett.co.uk/sstate2.html
SSTC is NOT that hard to build if one have some experiences with SMPS, it's basically the same theory. However it did cost a lot if you want it to build a reliable one.
Anyway, RMC, I like your idea about Plasma Gun, it looks so neat.
cheers,
Bluemotion
If you can get a rough value from the formula you can then tune your coil by adjusting its tapping point on the primary coil, or changing the size of the topload.
Bigger topload reduces the frequency of the secondary circuit. Bigger capacitor or bigger inductance (more turns) reduced frequency of the primary circuit. The frequency of the primary and secondary circuits must match or be as close as possible.
Now it seems that for the optimal use of the ignition coil I will need lower driver frequencies, witch I achieved by inserting larger value potmeter (100K, replacing the one connected to +12vdc).
The problem now is that the one 2n3055 can't take the current and fails after a few seconds of operating at the new lower frequencies. Can I use two or more 2n3055's in parrallel like the driver on this site WITHOUT the bfy51 in front of them or are there other types of transistors that work also (bc548,bc338,bc328,bc547,bf422,..)
thanks!
Is there a way that I could protect my timer from voltage spikes?
thanks!
All the info I can give you on voltage spikes is on the ignition coil driver page.
In a traditional tesla coil, there is a static spark gap and a capacitor. Is the point of the capacitor just to make the gap fire at just the right rate, or is there another purpose for the capacitor?
If I had a rotary spark gap with the contacts spaced just the right distance around the wheel (making the gap fire at just the right times), would I be able to run a tesla coil off of that, without the capacitor?
thanks very much for your help and info!
Thanks!!!
do you think i would gain any benefits from this setup, perhaps increaced power due to the better coupling, or maybe this could be the basis for a larger magnifier.
Lots of insulation would also introduce losses. A Tesla Coil works at a much higher frequency than other transformers so even dielectric materials will effect things.
Using a loosely coupled, air cored transformer allows a relatively high Q factor to be achieved.
secondary:
Diameter=75mm
turns=920
wire diameter=0.45mm
Primary:
Flat Spiral Coil
wire diameter 1.5mm
coil inner diameter=100mm
turns about 13
I was just looking through your shop and i found the line filter to protect the mains from tesla coil frequencies. I was just wondering: would it work to put the filter between the already-existing breaker box in my home and a new breaker box in my workshop to keep the high frequencies from my workshop from getting to the house power?
thank you very much, and again, i'm sorry for posting this in the wrong category.
http://deepfriedneon.com/tesla_frame6.html
I found out that for my tesla coil, I will need a capacitor that has a capacitance of .0068uF. My problem, though, is that I can't find a capacitor rated for a high enough voltage and that has that capacitance. Would it be possible to use one of my own homemade high voltage capacitors (probably not .0068uF) and change the primary circuit's frequency by doing something else, like tapping the primary coil in a different place?
6.8nF or 6800pF. Seven of these caps placed in parralel would give around 7nF. For the same frequency with a larger capacitor you would need to tap your primary so it has slightly fewer turns (or a fraction of a turn).
http://www.altair.org/tesla.html
here's my question: can i use a large set of AA batterys instead of a SLA?
Theoretically yes, but you would need loads of them which makes it very impractical.
Frank,
If it is allready smooth, then there is no need. Some varnish after may help though.
Do you have any suggestions on how to wind the secondary coil? I just want to know before i start.
Attached is a photo of my priary circuit. The Ice-cream container on the right is the HV filter, the PVC tube in the middle is the secondary coil(unwound) at the front is the Spark gap (with quencher and it's power supply), to the mid-left is the Cap bank (in oil) and to the back are my Ignition Coils. It is almost ready to run (after tuning). BTW-great website!!
Start by taping the end of the wire to your secondary former. Put the reel of wire on a roller like a pen in a clamp.
Try to keep the wire tight at all times to prevent it unraveling. Turn the former with one hand while using a finger or thumb of the other hand to press the wire onto it. Push the wire against each previous turn so that he whole thing stays tight.
Every so often put a tiny spot of glue so that it wont unwind too far if you slip or drop it.
Thanx
I am currently starting work on a small tesla coil (4 inch secondary). I found an ignition transformer on Ebay that uses a 120VAC standad wall input and has a 10kV, 23 mA output. I am awaiting a response from the seller to see if the output is AC or DC. It could be either because it is in an enclosure similar to an older NST, so there could be more in there than just the transformer. If it turns out to be DC ouput, do I need the driver circuit? Also, if it turns out to be AC, could I put a bridge rectifier in between the wall plug and the primary?
Thanks so much!
I would think the output is AC.
Anyway, a transformer needs an AC input so putting a rectifier before its input will prevent it from working. if you want a DC output you would put a high voltage rectifier on its output.
I have an ignition transformer very much like the one you describe, and it it used to ignite the fuel in an oil-burning furnace. Yes, the output is AC.
RMCybernetics:
If my tesla coil capacitor has a slightly smaller capacitance than I really need, would I make up for it by tuning the primary coil to greater or fewer turns?
My 4-inch diameter secondary Tesla coil is almost finished!!! I just need this last bit of information. Thanks!!!
This only works practiaclly to a certain extent because more turns means more inductance which equals more reactance against the flow of changing current. it should not be a problem as long as your number of turns is less than around 20.
I encounter difficulties in finding a BFY51 transistor. May i ask you others reference which could do the same job ?
Thank you very much
Any Bipolar, NPN transistor rated for about 1A will do.
der strom,
Don't rely on your calculations. You will always need to tune your TC after it is constructed as there are many factors the calculations don't consider. You should make your primary coil longer (more turns) than you calculated for and make it using uninsulated metal so that you can adjust the effective number of turns.
As of now, my tesla coil still isn't working, and I am wondering if that is the reason. Thank you!
Der Strom
IF DR TESLA COULD DO IT USING THEN YEARS TECHNOLOGY , IS IT POSSIBLE TO BUILD ONE TODAY,?
Thanks for your help
Thanks, great site!!
Here is my tesla coil secondary, shown next to a 12 inch ruler. Is there any way I can change the size of this coil without damaging the remanding windings?
An op amp requires 2 connections for power which are usually marked something like Vcc and Vee (Vcc is +ve). The two inputs are for a signal and will take a positive or negative input. If you make the non inverted input go high, the output will also go high, but if you make inverted input go high, the output will go low. The comparator compares the voltage on the inputs and determines if the output should be high or low.
Wider is often bettter, but you have to have it tall enough so that the output isn't to close to the bottom end. You could probably get a similar output from a coil that is half as tall and twice as wide.
Sincerely,
Der Strom
BIPOLAR HORIZONTAL AND TWIN BIPOLAR TCs
I have been inspired by this excellent web pages to do experiments with small TCs. However I am making not vertical TC but bipolar horizontal and twin TCs only. They are efficient and portable because there is no need for any Rf ground. Providing that you choose right coupling and tune precisely, all racing sparks should be eradicated.
Best performing is TWIN BIPOLAR - in nutshell:
12 - 24V battery/ sq.w. oscillator 555+393/8x2N3055/ two ign.car cs. antiparallel/ HV diode=80x1N4007 in the tube filled with mineral oil/ SG=copper tubes+fan=3x2mm gaps/ primary cap. 12.5nF./
Twin TCs: Secondary=70mm OD, 850 turns of 0.33mm(28awg). Both coils were made identical as best is possible, wound in the same direction. Toploads: tin circular containers 19cm x 10cm and you get as a bonus Danish biscuits. Primary: helical 20cm OD,
8 turns of insulated HiFi flat cable (8awg). You can wind primaries either in the same or in opposite directions.Taps at 5 turns on each coil. If you wound primaries in opposite dir., you have to tap only one primary coil at the beginning and at the end of winding (1 and 8 turns).
Performance: 27cm streamers (24V). You can get thicker streamers by using of four toploads in the “double-decker” arrangement and retuning. Providing that all four identical toploads have sparking tips you can get double, parallel, horizontal streamers.
With bipolar TCs RF grounding is not necessary, because the second half of a bipolar has about the same function as the ground in a typical vertical TC (consequence of symmetry). The horizontal bipo is electrically similar to the twin (see No. 3047). The geometry is different. There are not two vertical secondary + prim. coils but only one continuous-wound secondary mounted horizontally with the primary mounted over the center of the secondary coil. The center of a primary winding is marked 0 with an equal number of turns each side of center. The tuning is done from the center of the primary by an equal number of turns each side of center marked 0. The voltage rises to a maximum at the ends of the secondary c. where the sideloads with the “rabbit ears” are. The sparks travels between them.
My favourite horizontal bipo – in nutshell :12-24V battery / sq.w. oscillator 555+393 /
4 x 2N3055 / two ignition car cs.-antiparallel / HV diode = 60 x 1N4007 in the tube filled with mineral oil / SG=copper tubes+fan=3 x 2mm gaps / primary cap. 7.9nF /
Secondary: PVC tube 60mm OD, 950 turns of 0.33mm(28awg). Sideloads: tin biscuit circular containers 19cm x 10cm. “Rabbit ears”: 2-3mm wire, well insulated by vinyl tubing to eradicate corona. Primary: helical, PVC tube 160mm OD,
8 turns-0-8 turns of insulated HiFi flat cable (8awg). Taps: 4t.-0-4t.
Performance: up to 22-23cm (24V bat.) and 18-19cm (12V bat.).
O/P 6V x 2 600 mA" means?
i found it written on a transformer.
how do u connect transformers in parallel?
how many step up transformers can i connect in parallel and still get spark?
(a)series
(b)parallel?
what should be changed for output of 10^6 volt?
I appreciate all of your help and patience with all of my "somewhat dumb" questions, and I want you to know that you have helped me a great deal with my journey to understanding high voltage electronics.
Once again, thank you soooo much for all of your help, and KEEP UP THE GOOD WORK!!!
sincerely,
Der Strom
I used to download pdfs from emule ... but it seems that it stoped ... anyone knows ? ... or some other like this?
Very good about Alternate energy with Tesla and free energy ;-)
No, the voltage output is not proportional to the number of turns. There isn't really a minimum current, it would depend on what you are trying to do, more current, more sparks.
It is currently running off a 12V 7AH battery that is about 2 years old.
It is powering a CRT flyback from a TV, which has an internal diode in tact.
The cap bank is made of:
6 paralell strings of 5x3KV caps in series. Their capacitance varies.
There are 2 30KV 1nf caps in parralell with the first caps.
The spark gap is simply 2 metal rods put close to each other that can be adjusted. It works well.
All of these components are mounted in a metal computer case. This is ground for the secondary and the -0v of the primary coil.
The computer case is ventilated with the original fan, connected to a 9V battery inside the case, with a switch mounted on the case.
The primary coil sits on the case, and has a tapping clip to connect it to a tapping point on the coil. It is currently tapped at 3.3 turns.
The output is 1.3 cm plasma to air, and 7cm sparks to screwdriver running off a 12V power supply (from 240V mains). I understand that this is unsafe, but the battery gives about 3/4 of that output.
How can i increase output or improve design? Thanks
It looks like you have a lot of primary turns. It might be better to use less turns and with thicker wire. You would have to increace the capacitance of yout tank capacitor to compensate and allow it to run at the sme resonant frequency.
Also make sure all high voltage parts (such as the capacitor terminals and flyback lead are kept short and well insulated. You could insulate any bare HV metal using thick epoxy.
Great advice
awesome site!!
A capacitor stores energy not charge, you will need a diode unless you discahrge it betweemn each half cycle of the AC current
what wire can be used to make primary coil? what is the minimum awg value of the wire for this application?
There are many such example on the net allready. I would reccomend googling for NST tesla coils.
tesla fire,
Yes. The thickness of the wire depends upon the amount of current you want to pass through it. it is bes to be too thick than too thin. Copper pipe is a common choice.
Thanks!
Within a couple of days, I took the wire from an old MO fan and wound it around a cardboard (didn't have any plastic) tube and got about 650 turns. For my primary transformer, I used a flyback transformer and the driver shown above, taken from somewhere on michaelv.org. Since the flyback already has a built-in rectifying diode, I did not need the 16kv, 300mA diode I found in another MO. I plan to use this with my ignition coil. For my primary coil, I used 7 turns of 3mm diameter stripped copper wire, tapped at about 5 turns, mounted on 4 cardboard supports in a steep conical shape. I used 3 beer bottle capacitors, giving me a capacitance of about 2.5nF. For the topload, I used an 8cm (yes, centimeter) diameter aluminum pie plate flipped upside-down. Right now, I am getting 5 cm streamers to air (only visible in extremely low light), but only 1 cm sparks to grounded screwdriver. I was wondering if you knew why I'm getting such small sparks to the grounded screwdriver. I'm sure it is a good ground connection. Thanks for your help, as always!
Sincerely,
Der Strom
i d'nt find if he use a PWM OC10A
for drive ignition coils
in a schema see in " diy tesla coil " may i use a PWM as signal generator
thanks
sorry my ENGLISH is a broken english
thanks
Oh, I forgot to mention that I'm no longer using the transformer driver that I posted above. Now I'm using your power pulse modulator with my wall adaptor power source in series with the flyback. It works GREAT!!!
Sincerely,
Der Strom
Yes a pwm is ideal. No you cant use a spark-gap (eclateur) instead of RC1. Please use the translator I mentioned to you before.
der strom,
Glad you like it. Keep an eye on the temperature of the heatsink if you are going at 5A.
By the way, I used the equation on deepfriedneon.com for the capacitor/transformer match, and after filling in the equation with my own information (i.e. a different frequency other than the 50/60hz.), it said I would need a tank capacitor with a capacitance of 69nF. Does this make sense? My flyback transformer delivers about 15kv at about 15mA (maybe as much as 20mA).
Thanks a lot!
-Der Strom
I tried running my tesla coil without a high voltage diode after the ignition coil and, using a single beer bottle capacitor, I got faint streamers to air about 3 cm long. I just connected the circuit like the ignition coil was an NST, and it still worked. I assume, though, that since it wasn't DC, and the capacitor charged every half-cycle of the ~20khz output of the ignition coil, the capacitor was unable to charge fully. Because of this, I could not have a very wide spark gap, and therefore, I did not have a good output from my TC.
If you use a diode, you should calculate the RC time constant to charge your capacitor to the voltage you want. i.e. You can find what capacitance will charge to the voltage you want in that time.
Would this circuit work, or am I missing a few key components (it's a combination of your power pulse generator and the paralleled ignition coil driver)?
Thanks!
-Der Strom
then I to transform an amp-mêtre (1_5 A) in volt-mêtre (10kv -50kv) or in frequency-mêtre to test a PWM. thank you and better greetings
You should not connect your PSU in series with the load. You should link the grounds (0V) of the PSU's , then connect the +ve of your load to the V+ of your high current PSU instead of the other.
The current drawn is dependant upon ohms law. The impedance of your load limits this current. Even if you PSU was rated for a million amps, it would still only supply 1.7A.
The second diagram wont work. The way you add T2 is all wrong, so is the way you connect the second power supply.
Jango,
Not really sure what you are asking.
(1) where could I buy, on your site the radiator for 4 transistors 2n3055 (2) the diode is it special see 1917 DER STROM thanks so much
How is your circuit connected (I assume you are using the power pulse generator with PWM and the ignition coil driver that you showed at the top of this page)?
Thanks, once again for pointing out the incorrect connections!
Sincerely,
Der Strom
For this diagram is necessary it to include system (R-C1) between the D1 diode and the ignitions coils to avoid a tension of breakdown? thanks
Thanks a lot for your patience!
Sincerely,
Der Strom
Hello. Then I to directly connect a flyback and a PWM OC10A. Thanks
Yes, RC1 is useful in any ignitioncoil application to snub spikes.
Yes you can connect directly. The number of turns depends upon the voltage and frequency and duty. You just need to make sure that the current draw does not exceed the ratings of the PWM-OC10A
Yes, RC1 is useful in any ignitioncoil application to snub spikes.
Yes you can connect directly. The number of turns depends upon the voltage and frequency and duty. You just need to make sure that the current draw does not exceed the ratings of the PWM-OC10A
John-Paul,
Wow, that is quite an extreme version of a battery powered TC. Try placing a MOV or TVS (rated for some voltage below the rating of your transistors) between the C and E of each transistor, or between the inputs of each coil. Note that they heat up as they absorb over voltage, so keep an eye on them. Not sure what you mean by a 'cap soft start'
Der Strom,
Just google for "Comparator test circuit" or something similar.
Thanks for all of your help!
Sincerely,
Der Strom
Der Strom
1100 turns sounds like a lot for something just 35 cm tall. several hundred should be enough. Having so many turns mus mean your wire is very thin. Thin wire has more resistance and lowers the Q factor of the coil making it waste energy.
When you build a coil you must tune it otherwise you will get nothing. Read through the messages on this site for help on that.
Is your secondary coil connected to an RF ground? This can make a big difference on most coils.
Start small, make a battery operated Tesla coil so that the power levels are limited to non lethal levels. Please don't mess with mains powered high voltage transformers.
Thank's for all information !!
I would recommend you just build your own. It's the most fun way I know!
Yes, you may have to do a little research first, but trust me, it is well worth it!!
You can find most of the information you will need on this site-- right under your nose!
Good luck, and HAVE FUN!!!!!
I recently received several microwave oven diodes. I was wondering if they would be sufficient to rectify the output of two anti-parralel ignition coils.
Also, how do you wire up your rectifier?
Is if Full or Half bridge?
thanks
I have limited resources and I dont want to build it if it wont work.
I don't know becasue the important parts are not even labeled.
aldrin,
Non-polar, high current or pulse discharge types. Definatley not electrolyitic, they will explode! Ones made from rolled metal and polypropelene are good. Ceramic ones will also do for small Tesla coils.
I have a sgtc with the cap in parralel to the power source. I have a secondary of aporx. 900 turns and a variable spark gap. my power source is a zvs+flyback config. I can onlty get minor puple sparks coming out of the top and none with a topload. (I have tried many toploads) I think I even have the coils tuned.
I have a heap of MJ2955's. I wonder if I could use them instead of the 2N3055's for the coil driver.
Thanks
deven
The diameter just needs to be big enough to take the current you want to pass. Bigger than that would make no noticable difference.
Deven,
No. They are PNP type, this circuit is for NPN.
Note that this is potentially dangerous as the once earthed metal body or brackets are now floating at a dangerously high voltage. You should make sure to put it in a new case to prevent accidentally touching it.
See please my comment No.3047 (28th Aug 08).Bipolar twin TC and also horizontal TC work very well.Here is the question re TOTAL VOLTAGE TOLERANCE : I am using 12 polypropylene caps in series. Each is 150 nF and rated up to 2000 Vdc(500 Vac). I believe that total V tolerance = 12x2000 V = 24000 V. Cornell Dubilier caps. 942C20P 15K are not cheap, so I would be grateful if you check my assessment re total V tolerance of my caps all wired in series.
My studio is located on third floor. I can't use ground rode or water pipe (because my audio/video equipment dont like it) to discharg spark for change light texture. For now I use long copper wire that I leave on the floor..at the other end of wire (near tesla) I plugged small rode (in my hand) .
Before I try to plug it on outside fence and I never got shock but now in my studio with long copper wire yes ; )
Someone have solution ? or how Can I test ground ?
Merci!
So many diodes in series is not likely to work. They wont switch at exactly the same time so some are likely to be blown.
That transistor is fine.
JOSEF,
Yes that is correct. The capacitance would be 150nf/12 = 12.5nF
Jerry,
If you are unable to run a wire down the outside of your building to a rod in the earth, there is still an alternative. You can place a wire mesh over the floor under and around your TC. It should be at least several meters wide.
arccrazy,
Seems like your capacitor does not have enough capacitance. Are you sure you have constructed and wired them correctly?
TO JERRY: see coomments No. 3047 and 3075. You do not need groundng at all with bipolar TC.
and this air stream be made to carry teslabolts ?
if this can be done it will be a true trsla coil gun
A medium strength field
I am using the PWM-OC10A I bought, to drive a toroid transformer in open collector mode. It still blew the 555timerIC, LM393 and the 1N4007 diode and the track for the diode.
I am in repair mode now. What is the SP1 component? Also can I get an exact cct diagram to repair it?
Deven
Also those equations are meant for charging a capacitor every half cycle so no diodes are needed. With an ignition coil system you must use at least one diode.
If your output voltages and currents are unknown, you are just going to have to determine the best capacitor by experimentation. You will also find that certain frequencies will work best when they match your spark gap firing rate.
I researched the tesla sites and I’ve came across 2 diagrams and I was wandering if you could tell me the difference between them. I’ll make the wiring like on your site because I’m using tow ignition coils, just like in your diagram.
Thank you, Radu.
I'm not sure which two diagrams you mean. There's a lot of different ways you can make a Tesla Coil.
The first one is typical of an AC mains powered type. The second one uses DC charging. That said, either would work in either situation, but typically the first one is used as it can cause less stress on the transformer.
TW462,
If you have a scope, you should be able to get a readout through a voltage divider. Ideally your caps and diodes should be rated for at least twice the peak voltage of your supply. Sometimes this is not practical, so they should just be as high as possible. The ignition coils I've use will put out 20kV when not loaded. The size of cap you use (combined with the primary coil) will need to have a value so that the resonant frequency matches your secondary coil. If you have a look at the three DIY Tesla Coil projects on this site you can get some idea of the size of capacitor relative to the size of the secondary coil.
To get 10kV you need to disconnect any earth connection and take 10kV from between the output terminals.
While it may work to connect the secondary coil to the primary, I would not recommend it. First of all, this would add extra danger to the output streamers as they would be electrically connected to the primary tank capacitor making them capable of delivering deadly current. It can also create problematic feedback when not precisely tuned which may damage your capacitor or NST.
You previously advised me on at least one rectifier on the HV output to charge the cap, would an ignition coil wired up this way produce an output that is more negative than positive and require the diode to be reverse biased?
My question is based on a magazine article that didn't include any rectification on the HV output, it wouldn't be a problem to forward the schematic but i'm not sure whether that would cause problems with copyright infringement?
Many thanks
TW
This is fine. See the diagrams for this NST Tesla Coil
TW462,
Yes, you would reverse the diode if you reverse the input voltage. You can email the article to me. The legality of that would vary in different countries, but in most it would be considered as fair use as it is only for reference and not to be posted on the website.
1. No. Any similar high voltage supply will do. You can use one driver to power multiple coils. You just need to make sure that the combined impedance of the coils is not too low or it would blow the transistor in the drive circuit.
2. The Tesla coil primary and secondary coils do not heat up significantly.
The coil is not likely to get hot, but the arcs will be very hot. If they strike or come close to the coil, you may have problems.
Yes, you can just use 30kV capacitors, and the new coils in our shop will work just fine for it too.
Yes, but it would be better to remove T1, replace T2 with an IGBT, and connect the signal wire to R1. You must also have a common ground between the signal generator and the coil circuit.
David, Your diagram in #4765 looks ok.
Nicole, No, the resistors etc are needed to make the 555 run.
Jakob, You should add 'bleeder resistors' between the terminals. These are very high resistance resistors that will slowly discharge the capacitor when not in use.
You wont get a square wave, especially using a spark gap. Magnetic quenching will help, but the coils will still ring in a sinusoidal way.
You can use something transistor based such as our PWM-OCXi if you want very fast rise and fall times.