Instructables
Have you ever wanted to build a high voltage devices to make sparks like Tesla Coils, Marx Generator, and so on.. But find it too compacted or difficult to build?

Well, this instructable is for you! It can make create a few kilovolts of static-like sparks, and best of all... You can make it with only two things to make it, a battery and a simple mains transformer!

Before you continue, you should know a little bit of information about transformers, click here to find out.
 
Remove these adsRemove these ads by Signing Up

Step 1: Get the things!!

Like I said, you need only two things to make it, well, actually, three things - some wires.

  • 9 volt battery.
  • Mains transformer
  • Wires

The mains transformer, you can find those in just about any mains powered electronic devices, like VCR's, stereos, and stuff like that, you can also use a wall wart if you want. The best mains transformers you could ever use is found in digital alarm clocks.

Unfortunately, I burnt up all of my alarm clock transformers while ago... :( So I will have use a transformer from a VCR.

Step 2: Wire up the transformer

Okay, before we attach the wires to the transformer, you need to take a look at it first...

The two leads of the transformer that are connected to the mains power source, is the primary (the high voltage side), and the other two leads are the secondary (the low voltage side).
We are going to connect the transformer in reversed, I mean the primary (the high voltage side) of the transformer becomes "secondary" and the secondary (the low voltage side) becomes "primary".

So we are going to connect the battery on the primary (the low voltage side) of the transformer and we will get some sparks from the secondary (the high voltage side)!

Right, attach the wires to the transformer!

Step 3: Connect to battery and have fun!

Yen6Fs.jpeg
Connect either one wire from the primary (the low voltage side) to one terminal of the battery (don't worry, you can connect it any way round). Then bring two secondary wires (the high voltage side) very close to each other (about 2 mm) and then tap the other primary wire to the other terminal of the battery.

And then, you should see sparks on the ends of the secondary wires, and you may hear a little "snap" too!
1-40 of 357Next »
spirit x5 months ago

dc to ac is not possible without a capacitor and diode . isn't it ?

You mean ac to dc. Yeah it isnt possible. But you don't necessarily need dc for this experiment specifically.

JoeW3 spirit x2 months ago

I was taught in electronic school that in order to transform ac to dc you need a transformer along with a full wave rectifier (bridge rectifier) ( in which is four diodes), and a capacitor to filter out the remaining ac ripple. Now from dc to ac you need what is known as an inverter.

BitF1 spirit x4 months ago

if you just keep pressing the button it makes an ac current every time you press the button

modym1 month ago

Thanks for your great effort you have made to me ...but can I replace 9v dc of battery by 9v ac ?

Yes you can. It will generate sparks at ac frequency.
thanks... God bless you ... your site has good information and very safe ... I have no risks.

thanks ... God bless you.

ualbuquerque2 months ago

I got a transformer from a fluorescent lamp, but it only has 3 pins, what do I do?

MiitheWii6 years ago
if you leave it on, will the spark stay on. i mean like if you were to hold down the switch instead of tapping it.
No, that wouldn't work because the reason the transformer works is because of alternating current. Electricity is created by an magnetic field that alternated back and forth causing an electron flow. if you just hook it up to the battery and leave the button on then it will create one high voltage pulse from the initial magnetic field but since it doesn't change there will be no voltage continued after that first pulse. that is why you need AC power for transformers. I Suggested a 555 timer because it alternates and would be good to trip a transistor or relay to act like pressing a button really fast. The primary coil in the transistor creates a reverse current feed back after you stop applying power to it so i keep frying the transistor even with a diode at the end. Does anyone know how to make this work better because it is a great idea to step up voltage.
belangers Elipsit3 months ago

Use a Hexfet to drive the coil and the 555 to drive the hexfet. Connect the source through the hexfet direct to a battery to absorb the back emf spike by adding a capacitor into the circuit, then through a diode directed only to the battery post for the spike's concern.The higher charges will concentrate and release into the battery correctly. If the voltages are ultra-high, I would consider putting a ground initiated back emf "Spark Gap", which you would do by adding additional circuitry that would activate instantaneously upon removal of power to the transformer coil. This would at the same time connect the transformer coil, cap or caps (as a bank) to absorb the charge from the back emf pulse, and at the exact time of avalanche, the other side of the transformer coil is disconnected, and the battery is connected to the back emf path to absorb and suck up the energy safely. If you leave the transistor in the circuit while removing power, unless you build precautionary circuitry, I'm sorry , but the spikes vary with sharpness, and as you know are very destructive. If the waveform gives this very sharp spike while shutting off, the voltage gets more powerful and could easily douple , triple , or even quadruple, sending the ultimate surge back into the transistor or even further, with high enough voltages to jump to the controller, 555, or whatever chip is used, frying that.

Take a few minutes and Google "back -emf protection circuits" to see what there is to offer. They may have these circuits printed right in the product datasheet. Sometimes before designing a circuit, I look to see what great products are out there that have the schematic published online, which drives a coil , adding protection. Some manufacturers have a discharge pin of some sort that you could add a resistor to ground on the output, which protects the unit against back emf and other electronic anomalies that could happen as a result of powering down a large inductor coil. Most electric motors that use relays have grounding resistors to eliminate this voltage build up. Some circuits out there have already been created to use these pulses for charging things, so, my guess is the battery will be the best protection one will find, possibly even caps, which I use without any issues at all. The diode has to push the current the way you wish once you disconnect.

Marc

Andyc1 belangers3 months ago

Why don't you just follow the KISS principle and add a capacitor(and perhaps a resistor) in series for the primary circuit?

wait since AC already alternates its current doesn't that mean the current is already pulsed in the transformer? Therefore it already creates fast high voltage
pulse. Why do u still need to add a transistor to further pulse the current
That only happens if the current going through the low-voltage side of the circuit is oscillating. If it were a constant DC current, you would only get a momentary spark when the primary discharges into the secondary as soon as you release the switch.
sorry did'nt think it through I do that occasionally
it actully wont, im not sure why, but ive built one and it dosnt waork that way.
BR-5494 months ago

Great job Plasmana. An excellent example of high voltage induction. For those whom electrical knowledge is lacking, a simple, cheap and safe way to observe a spark. For those who say this doesn't work.......you need to read more carefully. Plasmana said to TAP the positive terminal....not TAPE it. Plasmana did not say that you would get continuous sparking. You get one spark for one tap. Turn the lights down and you will see it. Thanks Plasmana. And 73's.

bossboy 474 months ago

hook up a moter to make the shock consistent.

wpnman9910 months ago

That's pretty awesome. I am looking into building an electric ignition spark system for an aerosol based flamethrower. (With a pistol grip for spray painting and whatever aerosol that is flammable). I am thinking this idea would work great. Thanks!

cool im using mine to build a ultra high voltage emp so far it only works on small items like iphones my sister killed me when i broke her 5S

mjcole826 months ago

This won't work. DC does not transform in this way. At most you might get a very brief spark when you disconnect the battery from the EMF collapsing in the opposite polarity.

private_17 months ago

if you want bigger spark than

Use a 9vdc to 240vac transformer then 240vac to 600vac transformer

wpnman9910 months ago

If I do get the transformer from a wall wart, what's the output I should look for?

jelte1234 wpnman9910 months ago

the lower the normal output voltage, the higher the voltage when run the other way around. Sorry, that's all I can say without more research...

Can U Tell Me How Can I Get Continuous Supply From The Transformer ? By Using A 9v Battery

I don't recommend trying that, since even for steady AC you should push the switch at least 40? times a second. you could just use a diode, but I recommend trying a step up converter. also, what do you need (+-) 400 v DC for? then I could maybe help you think something up.

How Can I Use A Diode The Transformer Has 4 Pins 2 Pins Of Primary And 2
Of Secondary . This Transformer Actually Converts 240 V Ac To 12 V Dc
So I reversed It And Now It Give About 220 V Ac As I Switch It On And
Off . I M Using It As A Step Up Transformer . I Use It To Charge My
Capacitor Bank . Also I Have Have Tried A Bug Zapper Circuit But My
Transistor Died Very Fast ( Disposable Cam Same Issue ) . So I Use This
Transformer Also I wanted To Make A Inverter I Tried To Light a CFl Yes
It Lights Up But It Is Difficult To Find Out That Is It Burning Or Not .
Yes IT Is . So Plzzz Send Me A Schematic For Continuous Supply .
Should I Use A Relay Or A 555 Timer And Can U Tell Me How Can I Use A
Diode . I Live In India So My English Is Bad And I I m Just 14

Hi Apillai,

I suggest that to charge a capacitor bank, you research some coilgun schematics. I've got one here:

http://www.instructables.com/id/How-to-make-Homemade-Railgun/ I haven't tried this one, but it seems like it would work? if it doesn't, just try something else for coilguns.

Thnxx But I Need A Portable One Yeahh I got a bug zapper work great thnxx for u r anticipation . thnxx and srry to disturb u

I think this might help:

http://www.instructables.com/id/How-to-make-Homema... If it doesn't, just search for some other coilgun schematics. good luck! I personally don't know about 555 timers..

If you're planning to do stuff with capacitors, make sure you know what you are doing or have an adult guide you, since if everything works there are hundreds of volts just waiting to zap you.

Good Luck!

I actually may have a need for 400VDC (or so). I was looking for a simple way to modify a simple solar light to power a voltage amplifier to deter small animals. I figure that I could bang these out on the cheap given a simple circuit and perhaps chase off many different pests depending on the design/bait. Thanks for looking !

Hello Farmer Ben,

you might be able to do something with the circuit from a disposable camera's flash! there are a ton of projects related to this on this site. If that isn't what you're looking for, you might try something related to coilguns. (they work with capacitors too)

Make sure you also have some way to only let it work on the targeted animals, and not on the neighbor's kid or small dog!! (you don't want any trouble)

Good luck!

indy19701 year ago
try this on get mechanical relay with a normally closed contact .
take the + from the battery go to the relay coil>> out of the relay coil to the transformer>> from the transformer to one side of the normally closed contact.
Then take the - battery to the other side of the normally closed contact. it will buzz the relay sending pulsed dc to the transformer stepping it up and giving you a higher frequency spark.
apillai5 indy19708 months ago

Can U Tell Me How Can I Get Continuous Supply From The Transformer ? By Using A 9v Battery

vgilankar1 year ago
What if I got an old transformer? reply plz!
how would i use the transformer if it has four connections on one side then two on the other side?
vgilankar1 year ago
If I try this with a 6v battery with other 3v battery would it be work same?
Erkel971 year ago
since increase in voltage means decrease in amperage (right?) and amperage is the biggest danger to humans with electricity, Can this be used to shock people?
Jaguar935 years ago
(removed by author or community request)
1-40 of 357Next »