OK so you have built a large
Van de Graaff Generator
now you want to take it a step further and up the spark current.

A good way to do that is to use a leyden jar and build up a large charge in it and watch the powerful sparks fly.

This Leyden jar is made from a 5 gallon bucket and stores enough electricity to kill you.

I strongly recommend building a smaller one unless you know what your doing.

The leyden jar is a very old design dating back to the late 1700's
Its simply put a high voltage high capacity capacitor.

Built properly and treated like a loaded gun you too can make your own miniature lightning bolts.
Trust me when i tell you that a discharge from this device is loud enough to damage your hearing so wear hearing protection.

I have experimented with high voltage for many years this is one of the more dangerous projects I have completed so please be careful. I accept no responsibility for your injury or death.

Have fun and please be safe,
Zachary M.

Next up parts list.

Step 1: Parts and Tools Needed


5 gallon plastic bucket
Roll of aluminum foil
copper pipe 1/2" diameter or larger
small piece of copper sheet
round door knob
spray glue (i used contact cement)

Drill with bits
masking tape

Step 2: Ready the Bucket

Remove the handle with the pliers and clean the bucket inside and out with alcohol.

Next you will want to make a perfectly level line around the bucket about 10" from the bottom.

I stacked some books next to the bucket and held a sharpie on them and turned the bucket around wile marking a perfectly level line.

Step 3: Tape It Up...and Spray

Tape along the line you just made.

now spray the out side of the bucket with a few coats of contact cement.

On a smaller leyden jar i would recommend aluminum duct tape, but you have a huge surface area to cover on this one.

let the glue dry...

Step 4: Put on the Metal

I started with the center of the bottom and pushed the metal into every crevice I could.

I also resprayed the bottom over the metal and put on another coat for a little more durability.

next do the side getting out all the wrinkles as you go along. If you used the thickest aluminum foil one coat is fine.

just coat up to the tape line. I let mine over lap and I cut along the tape with a sharp knife to make a perfect edge.

Step 5: Mark and Tape the Inside of the Bucket

Next I measured down the bucket to the top of the foil and made a mark on my ruler.

then I taped a piece of plastic to the ruler on that mark to make a makeshift gauge.

I then used it to mark the inside of the bucket. Simply but it up against the lip of the bucket and mark below the end of the ruler.

Step 6: Tape the Inside and Spray It

Tape off the inside and spray it as you did the outside.

Step 7: Foil the Inside

I started with the bottom and then glued strips up the sides.

I also cut off the excess and made sure the edge was sharp and level.

You can over lap the foil just spay the glue on the foil and let dry then apply.

Step 8: Center Post

I wanted a good connection with the center post so I cut the pipe so that it ends about eight inches above the rim of the bucket and soldered a piece of copper sheet 4" square on one end.

Step 9: Center Post Installed

set the center post in place and glue it down with strips of foil.

Make sure its as close to center as you can get it.

Step 10: Put on the Lid, Opperation

Now simply drill a hole in the center of the lid and put it on the bucket.

Secure the door knob to the tip of the post and its done.

I will be looking for a better ball for it and will post the changes later.

Now that you have built it simply connect the doorknob to a VDG and charge up!

For a big spark connect another door knob to a pole that is connected to the outside of the leyden jar.

It will be the negative side and the center post the positive.

To discharge it without hurting your self, make a set of discharge tongs from the old bucket handle and put them on the end of a fiberglass pole. Then short out the outside of the bucket to the center node. Yes a large spark will occur.Touch the outside of the bucket first so as to not burn holes in the aluminum.

I will add a video when I get my test stand done.

Thanks for looking and please be safe.
Zachary M.

<p>what liquid did you use inside, iv'e heard plain water works but iv'e also heard people use a 50/50 mix of baking soda and water, and a 50/50 mix of vinegar and water</p>
<p>There is no need for a conducting liquid in this case because the foil on the inside is right up against the inside wall. The liquid is normally only used as a work. The liquid fills the volume, effectivly bringing the conductor to the sides of the bottle. </p>
<p>In that case then couldn't you scale this down to be just as effective or is the surface area that important?</p>
<p>The surface area is one of three things that are important. The other two are materials and distance between the foil. Capacitance will go up as surface area goes up and the distance between the foil goes down. If you are mathematically inclined, the equations for a parallel plate capacitor are applicable here since the diameter is large. </p><p>Long story short, yes, surface area is very important. </p>
so how many pF is that? migtht get a bigger bang (but less often) just connecting a bunch of 10kV 3300pF ceramic caps in series (about 60 cents ea). 100 of those = 16.5J assuming full voltage. Dunno how long they'd last in a dead short 2-3 times a minute tho as the plates are very thin.
you say you have had alot of experience with high voltage devices you should build a marx generator
just one thing DON'T USE A WOODEN HANDLE wood can conduct electricity use somthing like fibre glass or put the discharge pole onto an RC car
Although wood will conduct, there isn't much danger as long as you contact the outside foil layer before approaching the center electrode. If you touched the middle part without a good contact to the outside foil, the electrical discharge might go through the handle and YOU to ground, instead of through the proper path...
a good point but better safe than electrocuted also if the pole is damp or has been in a humid room(like a basement) then it might still travel up the pole and give you a nasty shock
I like life without electrocution....
But...electrocution is fun...unless you actually die.
I probably would have to disagree with that, except for very small voltages (like rubbing your feet on a carpet and touching a doorknob). :D
which isn't possible<br />
I don't think that's right. I'm pretty sure wood is an insulator, although if theres enough moisture and impurities it can conduct very well.
actually if there is a vein of sap that has been dried the right way it can conduct electricity too, especially if carbon/soot lands on it (which is also conductive) wood is a very heterogeneous substance, not good to mix unknowns with high voltage
&nbsp;wood does indeed conduct electricity - &nbsp;in these pictures you see a plain chunk of 2X4 with a grounded screw embedded in one side. there is a hole in the block (near the center of the fractal burn) that has had a high voltage probe embedded in it. when charged, the electricity burns patterns into the wood that resemble fractals. <br />the power source for this experiment was a NST, connected to a&nbsp;Cockroft Walton voltage multiplier, to ramp up the volts to 120KVDC - then run through 3- 1 gallon SWC caps, with neg being connected to ground and the screw shown coming out of the side of the block- pos is connected to a probe with a 2 foot pvc handle and ceramic baffles (to allow me to move it when it is on.)<br />it looked really cool while it was burning, but no actual flame was present- more like a orange plasma- it also burns from the inside of the block out- very interesting phenomena.
hmm- pictures didn't show up
I have converted an old go cart flag holder into a discharge wand. Thanks for the safety tip!
Finally, Made on<br><br>Pfarmkid
I just decided to connect one to a 12kv 60mA neon transformer (no rectifier) and the arcs are deafening. But after a few seconds the aluminum foil around my connections was vaporized. So for high current I would suggest using sheet metal instead of foil.
Your problem isn't because of the high voltage, the aluminum foil was vaporized because you have used unrectified current and there is no way you can charge a capacitor with that since the pollarity is periodically changing, it will arc inside the capacitor and melt the connections. You have to use high voltage DC current.<br>Good luck :)
A rectifier would be helpful, but the capacitor is still charged in within a half cycle of the ac waveform, much like the tank capacitor in a spark gap tesla coil.<br> The foil on the capacitor holds up until I start drawing arcs.<br> If I could solder the wires to the foil it would probably work, but I would have to do that before the foil is attached to the bucket so it doesn't melt.<br> I still plan on making a 20KV full wave rectifier from 80 1N4007 diodes though. It's a lot cheaper than buying high voltage diodes.<br>
At high frequency the wavelenght is shorter than the normal AC (50-60 Hz), also the corona is formed by the nasty spikes, that's why the current goes through the dielectric and destroy the capacitor plates.<br>I suggest you try with a flyback transformer since it already has rectified output (HV diode). I did this with mazzily oscillator and jar capacitors.<br>It might work with the 1n4007, but remember to submerge them is oil, otherwise it will arc on the outside.
also how maney amps do you get when it dischargis? becous you know its the amps that kill
y is it that im the only one that every time i try to make a vdg i fail its sooooooooooooooooooooooooooooooo frusterating <br>
will it hurt if you touch it?
Nope it will kill you, quite dead, no pulse, to the morgue you go....
yes, seriously, dead D-E-A-D
I have a simple question regarding the point of making sparks with your VDG.<br><br>I understand how you are demonstrating the effect of your &quot;Leyden Jar of Doom&quot; but to make a spark, wouldn't it be simpler to just connect a grounded metal electrode close enough to the VDG so the VDG would discharge directly to the electrode, instead of using the leyden jar as a &quot;middleman&quot;?<br><br>However, if you wish to discharge the jar LATER, then I see why this is effective.<br><br>Thanks
Yes you can make sparks that way, with just the VDG, but the Jar of doom gives more surface area than just the sphere and in turn lets you build a higher current, and give you a stronger more powerful spark. A spark that can kill instantly. The sparks from the VDG are harmless unless you have a pacemaker. The sparks stored in the Jar is deadly.
So surface area = more current? I would kind of think that it might be less, as there's more resistance, but that's with my basic knowledge? Can you please explain why there would be more current?<br><br>I plan to build my own hand-cranked VDG this weekend :)
I know it was a couple of months ago but it looks like you didn't get an answer and it's an interesting question:<br>Yes, surface area is a factor but just one. Time and source voltage are the others.<br><br>Any time you're dealing with a capacitor you can think of it as working by stacking a bunch of electrons up on the plate connected to the source (in this case the VDG).<br><br>The more electrons you can get back out during the discharge the more current you'll have. Working toward this goal are . . .<br><br>1. The more surface area on the plate, the more electrons you can stack up.<br>2. The higher the voltage applied, the faster you can stack electrons and . . .<br>3. the longer you let them accumulate, the more electrons (potential current) you'll have stored - up to the maximum saturation of the plate.<br><br>Other factors are involved like the thickness of dielectric between the plates (inner and outer foil in this example) and how well that dielectric resists letting the electrons cross the gap but those are the main three that determine what current you're going to get out at the end.<br><br>VDGs and other electrostatic generators are mostly harmless because even though they can generate extremely high voltages the electrons trickle off continuously and don't &quot;bunch up&quot;. In this monster, a LOT of electrons bunch up and when discharged over a fraction of a second deliver that bunch of electrons as seriously high current. I would like to see some numbers on this.
Good answer, I have been away for some time, to many websites to maintain!<br>Thanks Kholt42
1 liters = 0.264172052 US gallons
i've dealed with high voltages, but this<br>i'll better stay away from build somthing like this.<br>maybe i make a small one<br>
Question:&nbsp;&nbsp; the <span class="mw-headline" id="Dielectric_dispersion">Dielectric dispersion of glass is pretty poor, is the plastic of this type a lot better for &quot;holding a charge&quot; ?&nbsp;&nbsp;&nbsp; <br /> <br /> I&nbsp;have never had much luck with glass jars myself. </span>
Glass works well for me, but plastic seemed to be better, maybe it was just the ease it was built ...<br />
yes it is and to save on foil and get more capacitense i recomend using salt water lyden jar<br />
I&nbsp;tried an oil once that &quot;supposedly&quot; had a high dieletric constant,&nbsp; but apparantly the glass jar I&nbsp;used was too permeable.
Wow, that is a very nicely built leyden jar! Thank you for posting that, you have given me better ideas on leyden jar construction, 5 stars!
Thanks! be very careful !!!
Yes, I will... I have experiences in high voltage.
Ii have a little experience...i just don't like the loud spark that comes with it. Even just discharging little tiny camera flash caps freak me out
who dosent lik the smell of ozone an the crack of a high voltage ark.<br />
Same here.
That is why i use lightbulbs in series to discharge my caps. <_-(that is supposed to be a wink)
well, a wink is like this:&nbsp;&nbsp; ;-)<br /> but i guess sometimes it's ok to get away from the norm and do somethin different (like touching the end stupidly)<br />
I have a little experience with HV too, unfortunately for me, mine were not pleasant experiences :-)

About This Instructable




Bio: Electronics engineer with allot of mechanical design expertise
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