A
Hand Held Tesla Coil Battery Powered 'Plasma Gun'
The design for this Tesla Coil is based on the larger DIY
Tesla Coil project but with the aim of getting a much smaller and
portable device. A Power
Pulse Modulator circuit is used to drive two small high
voltage ignition coils wired together in an 'anti-parralel' configuration.
The output is rectified and used to charge the tank capacitor of a small
spark gap Tesla Coil.
The device is packed into the casing of chepo £10 cordless drill
from B&Q. This drill used a 12V battery and comes with a charger which
made it ideal for the project. The ignition
coil driver circuit used takes a direct 12V input which is connected
using the original switch from the drill.
This video clip shows the plasma gun causing a nearby light bulb
to light up as if it were a plasma globe.
The high frequency, high voltage from the plasma gun causes the
Argon gas in the light bulb to become ionized. This creates streamers
that are attracted to the fingers holding it.
The device draws about 6 amps from a well charged battery which makes
the total power consumption to around 72 watts. Unfortunately this low
power means the plasma arcs will be limited in size, but since it is hand
held that's probably a good thing. The typical length of the output arcs
is between 5 and 7cm.
Such a small Tesla Coil inherently has quite a high resonant frequency
which in this case is about 500 MHz. This frequency is too high to feel
as electric shock but when being zapped you can feel the low frequency
component of the spark gap firing rate.
Hand Held
Portable
Battery Powered
Trigger Activated
Plasma / Flame discharge
The main driving circuit is a type of pulse
width modulation circuit with protection against high voltage spikes.
It is adjusted to get the maximum output from the two ignition coils.
The two ignition coils were stripped of the casing in order to reduce
the overall size and allow access to the internal wiring. The inputs are
wired in an anti-parallel arrangement to help keep the charging voltage
high when under load.
The HV outputs of the spark coils are connected to a rectifier (D1) made
from four HV diodes potted in epoxy resin. Connected to this is a small
smoothing capacitor (C1) which helps to reduce the ripple in the HV DC
output. The tank capacitor (C2) is charged from the HV DC supply via two
RF chokes (inductors L1 & L2) which serve to prevent the RF oscillations
of the TC primary circuit from interfering with the rest of the circuit.
The previous battery powered tesla
coil design needed to be well connected to a good RF ground such as
a metal rod in the earth. Without this the output would be limited and
the driver circuit would be prone to failure.
With
this mini tesla coil the RF ground connection is made by connecting it
to a copper pad on the handle.
The body of the person holding the device is used as the RF ground and
the large area of copper ensures the energy is spread out to prevent RF
burns.
In most Tesla Coils this would not be safe at all but this device is
very low power so there is little risk of electric shock. The RF its self
probably isn't too healthy though!
The TC part (Tesla Coil) uses the common single static spark gap and
flat primary design for simplicity and size. The primary coil is closely
wound around the base of the secondary with several layers of insulation
tape preventing flashover.
The topload sphere is made from a metal draw handle which has been drilled
to allow gas to be ejected from the end. A pipe from this sphere runs
down the inside of the secondary and to the back of the handle where it
can be connected to a gas supply.
Using noble gasses such as Argon or Neon will cause the output arcs to
be forced along the flow of gas. This allows the plasma to be directed
in a straight line from the tip of the plasma gun. It is also possible
to use butane gas which makes this thing into some kind of flamethrower
- plasma gun hybrid. The electricity is conducted along the flame from
its tip. You can see photos of this effect on our plasma
page.
Apart
from making cool arcs of plasma, this device even transmits wireless
electrical power. It can light bulbs and fluorescent lights just
from being nearby.
The interference created by this wireless energy can cause all sorts
of electronic devices to switch on and off or start behaving erratically.
This is because the energy is causing tiny currents to be induced in the
tracks and wires in the devices. If a simple circuit had a matching resonant
frequency to that of the plasma gun, it would be possible to collect the
wireless energy from a greater distance.
There are several improvements that could be made on this design which
could result in a greater power throughput and therefore bigger arcs.
The spark gap is just a single gap which has been seal inside a plastic
case for safety and size. This sort of switching will have poor performance
due to quenching difficulties and oxide buildup. A solid state version
would be better but it would likely be larger and considerably more expensive.
A larger topload would allow for larger breakouts, but it would also need
more primary capacitance. The secondary coil is also rather long relative
to its width. Ideally this would be shorter and wider.
In conclusion this was a fun project and we hope you find this information
useful and interesting.
Some comments/questions are hidden. To include them below, click here
The information provided here can not be guaranteed as accurate or correct. Always check with an alternate source before following any suggestions made here.
I would like to know two things about your new project.
1) Where does one obtain the HV diodes rated at 15kV...do you know if RS components do these or is there an alternative source from old equipment?
2)Is the final tank capacitor a single capacitor or an MMC? I assume it's the former.
High voltage diodes and capacitors can be scrounged from an old TV set or computer monitor. Large color sets put out 25 KV or so. And the power supplies can be used for other projects too..Just BE CAREFUL cuz that kind of stored energy can kill you!
Dude, This is pure class. Good to see your making it on hackaday website.
Should make it so you can fire ionised gas out of it so the sparks can go better.
Hey there keef, glad you like it. The bottom picture is supposed to show Argon being fired from the end. Unfortunately my digital camera is pretty rubbish for this sort of thing. I'll get some better ones with my SLR at some point.
It works well using Neon too, bright red. If it's forced out through a tiny opening it will make a long straight needle like plasma jet.
"The body of the person holding the device is used as the RF ground and the large area of copper ensures the energy is spread out to prevent RF burns."
Possible to use an RF antenna 'dummy load' here instead? (Just in case somone wanted to up the power)
Hi there. You all have some great projects -- great ingenuity! I have 2 questions:
(1) Is the gas line neccessary, or only for the purpose of emitting streamers from the end of the "gun" itself?
(2) What would you estimate the total cost of the project to be?
Thanks, and good job!
The gas line is not necessary. It is just an added extra for directing the plasma out in a straight line. Without gas flow, the streamers will just look like those from a normal Tesla coil.
Rough costings as follows;
Cordless Drill - £10 Drive Circuit - £40
2x Spark Coils - £30
4x Diodes - £8
3x Capacitors - £5
RF Chokes - £1
Topload Sphere - £3
Coils & Former - £5
Spark Gap - £3
Time to Build - Priceless
TOTAL £105
That's buying everything new, you could probably lower the cost by using salvaged parts and also using the PWMOC10A kit instead of the ready made ones.
Higher power, and it runs from batteries. This ciruit uses transistors and compact coils to 'invert' the DC into HV AC for charging the tank capacitor. It also hase the gas jet feature.
Nothing that would be immediately noticeable, but excessive exposure to any source of RF would probably not be good for you. Although the mobile phone companies would probably disagree.
Just be careful... telsa coils actually produce
radiation... I wouldnt
want to be exposed to that.Just look at the way Tesa and most of his
associates died...Being blasted with x-rays just because it looks
cool can really be a bad decision.
Richard did you talk my wife into buying me an 18 Volt cordless drill for my Birthday. I never asked for a drill and now you come up with this idea. I guess the drill will have to break sometime.
By putting a UV laser in there you might be able to generate a sustained path of ionised gas between the unit and the target. just have it fire out the hole in the topload sphere.
Set Phasers to tickle!!
Just found this video of an amazing hand held tesla coil. It needs to be plugged in to the mains but it's certainly impressive. Well done JM Labs and teslacoil.net
It would tingle quite a bit. The arc jumping to a finger would possibly cause burns if left for several seconds. The RF electricity traveling through the body is probably not good for you either.
i like this its given me a great idea.
get a massive can sized capacitor full of tonnes of electric like with the can crushers, and use that instead of batteries so instead of a steady thing like that you could do what the posted vid does but have to reload each shot.
Ah, memories of my high school physics class. Mr. Flanagan left an insulation tester gizmo running on his lab table and left the room momentarily with the warning "this thing's hot, so don't anybody touch it". Of course, the class machos all checked it out. It resembled a soldering iron to the extent that it was line powered and had a bluntly tipped metal probe, but the handle was big enough for two people to hold with both hands. It could throw a spark about 2 inches and if you were the sparkee you wouldn't be inclined to try it again. It was our physics teacher's most memorable practical joke.
A very interesting device, I have thought about making one myself.
I think your idea based on the classic tesla coil is good, and the working unit is excelent.
If i was to make one id try to go solid state all the way, it may give you better power efficency over the traditional spark gap method.
I would also be very tempted to construct an aditional coil and make the system like a magnifier, this will help lower the res frequency down to more manageable levels, as well as giving you more of a voltage feild.
if the frequency is low enough, you may even be able to use ferrite powder, or bits of ferrite in the center of the sec tube, to improve coupling.
I doubt that very much indeed. The transistor was not invented until 1947. This device contains a power MOSFET, 2 IC's containing hundreds of transistors and rectifier diodes. The HV capacitors (condensers)here would have been impossible to make back then and an equivalent would be much larger. Even the battery stores much more energy per unit mass than would have been possible. The noble gas would have been very hard to get in 1938. Oh yes, it is also cased in this mystical substance called plastic!
I noticed you mentioned that argon gas was being used to create the arc in one of your pictures. Does this generate much heat, or UV light, it just seems very similar to the plasma weld TIG effect. (if it does produce any UV light you may want to avoid looking at it, as it can cause "arc eye")
No more significant heat or light is produced by using Argon in this system. The output current used here is very very low so the plasma temperature stays relativley cool compared to a TIG. The heat/light produced will be proportional to the current flowing in the arc. This uses something less than 1mA (0.001 A) where a TIG will use around 200A.
My son is in second year electrical eng. and wants to do a second major in physics
I am looking for Christmas ideas and wondered if I could but everything needed for this project as a kit...except the drill of course. I know nothing about this stuff and think I could easily spend a hour on this site just trying to find all the parts. It would be great if a package deal were available with basic instructions or the like. Thanks
The only parts we have on sale for this projects are linked in the parts list here. The coils of the Tesla Coil can easily be made by winding enameled (insulated) copper wire around a plastic tube. The actual dimensions of the coil (L4) can be different to that shown but this would mean that some other adjustments (C2 and/or L3) would need to be made to make it match. There are many variations that could be made to this project. Changing some of the parameters and observing the outcome can be a good way to learn.
It is not steady if you just have diodes. You would add a big capacitor after to smooth it out (This is what C1 is for in the diagram). I posted a diagram about this somewhere for somone, but I really can't remeber where unfortunatley. If you find it let me know the page and msg number.
If by voltage you mean the input voltage, and if my vary you mean increase, the result would be a proportionally increased output power and faster firing rate.
Hi!
My friends and I are making this for a high school chem. project and we would like to know a couple of things.
1) What are possible dangers? Are measures of safety did you take when you made this?
2) Do you know where we can get the parts other than your site (we need it soon but your shipping date is past the due date). What stores do you recommend?
3) Why a drill? Are there any parts in the drill (aside from the battery) that is critical?
Dangers are from fire, electric shock (causing you to possibly injure yourself indirectly), and interference with nearby electronic equipment.
Coils from an autospares supplier, maybe you can find other parts in a local electonics shop.
Drill just has a convinient shape, battery and switch.
Man i built one out of capacitors, couplings, copper wire,etc. but the box was a fire work box...I was wondering if you would post a version of Mr. Tesla's hand held oscillator...that would be cool thanks for pictures and all. Continue to light the world.
The charging current for the capacitor here is low and via some diodes. This just helps with preventing HV spikes getting back to the circuit. When charging from an AC transformer like an NST, it is not so important.
I am building a Tesla Coil, and want to know if a capacitance of 0.0014 uF @ 90KV would be enough to give good results. The coil is driven by 2 Ignition coils (12V SLA powered), and has a secondary height of about 70 cm.
Thanks for your help.
Frank,
The output from the ignition coils does need to be rectified.
FB,
1.4nF is quite small and will therefore create a higher frequency resonance than a larger capacitor would. You may be able to compensate with more turns on your primary coil.
It is all about matching the resonant frequencies of the parts so you have to make your coils match the capacitor used.
Also, how are the primary and secondary coils attached to the machine. I can't really tell from the pictures. And one more thing, can any of these parts be salvaged from appliances you might find around the house? If so, which parts, and what could you find them in?
Yes plastic. You are seeing things. It has to be a coil or it would not work. It is a coil of fine wire wrapped on a plastic tube. All attached together with epoxy resin. You are going to have to use your imagination to find the parts.
Huh... It appears the primary coil is attached to some part of the circuit in the pictures, but it doesn't say anything about that in the diagrams. even with that, how is the primary coil attached to the machine, and do the primary and secondary coils touch?
You must learn more about a Tesla coil and how a Tesla Coil works or you will not be able to make this project work.
Yes the secondary wire is enamel coated copper wire aka magnet wire.
You have a lot to learn before you should try a project like this or it will just not work. I can't possibly explain every detail.
I have read up on tesla coils, and feel I really understand how they work now. My only remaining question is this: where else can I find a "Power Pulse Modulator" that will work for this project? The one sold here has been back-ordered 14 times, and I was wondering if you knew of anywhere else where they sell this item. The only ones I have been able to find don't match the specs of the one sold here.
I apologize for all the questions I have been asking, but my father has these questions about this project that I really don't think can be answered by anyone but the person who made this device.
First of all, why are RF chokes necessary, and what problems are caused with the device if RF chokes are not used?
Also, It says the spark coils generate about 20kv of energy. Why do you only need diodes and capacitors that can tolerate 15kv?
Lastly, with the primary coil having 5 turns and the secondary having 520 turns, with a direct relationship between the increase in number of coils to increase in voltage, wouldn't that mean that the 20kv put into them by the spark coils would increase 100-fold to about 2000kv?
RF Chokes are simply coils of wire or inductors. They are used to allow DC to to pass through them for charging the capacitor whilst they block the high frequency from the primary coil+capacitor from getting back to the diodes.
If you dont use the chokes, when the spark gap fires, it can cause current or voltage spkes which would damage the diodes.
The coils are constantly loaded in this circuit and will never get as high as 20kV, infact the spark gap was set to fire at around 5kV but your components must always be rated significantly higher.
There is no direct relationship between the number of turns in this type of transformer. It depends on many factors.
Nothing is new under the sun... I used a model t ignition transfoemer (they were self exited with a vibrating interrupter) a spark gap and resonating capacitor made of plate glass and aluminum foil with a copper tube primary and a secondary wound on varnished paper carpet tube and that was in 1955... In 1960 I made a 7 ft tesla coil with a neon sign transformer and a pair of 811A's (large transmitting tubes) driving a copper tube primary with an 8foot secondary (also paper carpet tube) Blanked out radio reception for 10 miles around... didn't need transistors OR plastic
The cround of your coils depends on the type. It is normally connected internally to the primary coil. If you cant open it to seperate it, you can just leave it out.
The ground is on your power supply or the negative terminal of your battery.
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A
Hand Held Tesla Coil 
With
this mini tesla coil the RF ground connection is made by connecting it
to a copper pad on the handle.
Apart
from making cool arcs of plasma, this device even transmits wireless
electrical power. It can light bulbs and fluorescent lights just
from being nearby.
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