Leyden jar of DOOM!

Picture of Leyden jar of DOOM!
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.

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Step 1: Parts and tools needed

Picture of 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

Picture of 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

Picture of 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...
fuqthegovt1 year ago
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
fd935 years ago
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
Spedy fd935 years ago
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...
fd93 Spedy5 years ago
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
nickademuss (author)  fd935 years ago
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
megamarine fd934 years ago
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
 wood does indeed conduct electricity -  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.
the power source for this experiment was a NST, connected to a 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.)
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
nickademuss (author)  fd935 years ago
I have converted an old go cart flag holder into a discharge wand. Thanks for the safety tip!
Pfarmkid2 years ago
Finally, Made on

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.
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.
The foil on the capacitor holds up until I start drawing arcs.
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.
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.
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.
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.
It might work with the 1n4007, but remember to submerge them is oil, otherwise it will arc on the outside.
joehudy3 years ago
also how maney amps do you get when it dischargis? becous you know its the amps that kill
joehudy3 years ago
y is it that im the only one that every time i try to make a vdg i fail its sooooooooooooooooooooooooooooooo frusterating
will it hurt if you touch it?
nickademuss (author)  dragonsniper3 years ago
Nope it will kill you, quite dead, no pulse, to the morgue you go....
nickademuss (author)  best_brothers3 years ago
yes, seriously, dead D-E-A-D
I have a simple question regarding the point of making sparks with your VDG.

I understand how you are demonstrating the effect of your "Leyden Jar of Doom" 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 "middleman"?

However, if you wish to discharge the jar LATER, then I see why this is effective.

nickademuss (author)  Epic_Canadian3 years ago
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?

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:
Yes, surface area is a factor but just one. Time and source voltage are the others.

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).

The more electrons you can get back out during the discharge the more current you'll have. Working toward this goal are . . .

1. The more surface area on the plate, the more electrons you can stack up.
2. The higher the voltage applied, the faster you can stack electrons and . . .
3. the longer you let them accumulate, the more electrons (potential current) you'll have stored - up to the maximum saturation of the plate.

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.

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 "bunch up". 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.
nickademuss (author)  kholt423 years ago
Good answer, I have been away for some time, to many websites to maintain!
Thanks Kholt42
nickademuss (author)  h0meIandsecurity3 years ago
1 liters = 0.264172052 US gallons
xeon_hl23 years ago
i've dealed with high voltages, but this
i'll better stay away from build somthing like this.
maybe i make a small one
Goodhart4 years ago
Question:   the Dielectric dispersion of glass is pretty poor, is the plastic of this type a lot better for "holding a charge" ?   

I have never had much luck with glass jars myself.
nickademuss (author)  Goodhart3 years ago
Glass works well for me, but plastic seemed to be better, maybe it was just the ease it was built ...
yes it is and to save on foil and get more capacitense i recomend using salt water lyden jar
I tried an oil once that "supposedly" had a high dieletric constant,  but apparantly the glass jar I used was too permeable.
Plasmana5 years ago
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!
nickademuss (author)  Plasmana5 years ago
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.
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:   ;-)
but i guess sometimes it's ok to get away from the norm and do somethin different (like touching the end stupidly)
I have a little experience with HV too, unfortunately for me, mine were not pleasant experiences :-)
Mine were not pleasant experiences.

What? You mean the high voltage sparks keeps biting you?
Actually, except for one experience with my VW bug (30 years or more ago) and the Coil, I have been fairly careful with SUPER high voltages, but I did mark up my arm a bit laying it across two 220 v lines once. That was nasty.
Haha, you call 1000 volts (or something like that) SUPER high voltage? Imagine this: I one time experimented with a tiny tesla coil that gave off 100,000 volt sparks, but it then fail. Now I can go up to 60,000 volts with my marx generator... I have been shocked by the mains power (120v) when i was young... That is the hard way of learning that high voltage electricity is dangerous. :-) And because you said you have been shocked by 220v lines, do you live somewhere in Europe? I thought you live in America!
Well, the output of the coil I spoke of ranged between 8K & 12Kv Some put out 20K or more and yes, I live in the USA. It was at a place I worked, the "hatchers" had 2 - 220 lines running into the timer circuits (think pre-1980 safety standards) and their motors (the motors were to tilt the trays of eggs so they warmed evenly. Anyway, I was required to open the main panel, and reach in there and turn the timer until the trays started to tilt, once they got halfway up (parallel to the ground) I turned the timer again to stop the motors. MOST of the electrical connections in the wiring / timer box were exposed. I laid my arm across two separate hot lines as i reached in. It threw me backwards into the next hatcher and made my arm a very funny non-color. BTW: The main line into most homes IS 240 (oh, I see why you asked, I wrote 220 and not 240, sorry), and is then split. Many offices now use an odd voltage compared to home use, which makes taking home supplies like florescent tubes, from the office, pretty useless :-)
PS: I also have a 10K DC power supply at home, nasty shocks can be gotten through normal insulated wires...for sure.
yuh. i got troubles in the insulation of my rocket launch rig
Yeah, and don't even trust HV insulation that is carrying HV an high frequency AC (from plasma globes), because it can go through just about anything. I had one time put my finger near the high voltage wire and there was a lot of purple 'mist' between my finger and the wire, it was quite cool, but then, my finger stinks afterwards...
Hmm, ok, thanks for the advice. I hadn't really thought about the insulation of the wire I was using, thinking it was rather thick, and grabbed it quite a few inches down from where it was bare, but then I started to feel a tingling in my hand, so I leaned forward and put my feet on the floor... ow! A bit of a nasty punch.
Ouch! That sounds like you really did have some unpleasant experiences...
Funny how I picked ELECTRONICS as a hobby when I had already become deathly afraid of being shocked LOL

It kept me safe from that point on I guess. :-)
There is one thing that is very odd, I very rarely get shocked and I have NEVER been shocked by a disposable camera's 330v capacitor. While I hear so many people suffer many shocks...? Why is that? Is it because the people who has been shocked so many times are nervous about getting shocked? (I don't get nervous.)
some people don't know what their doing...or whats going to happen so as they open up the thing they sometimes accidentally get shocked by the cap
and i speak from experience... unfortunately...
Hmm, I am not nervous (although I have been shocked when no electricity was present :-) but I am cautious. I have done a number of dumb things before I ever understood what I was doing.

Like I remember making our own batteries at school, with paper towels and lead, in a saline solution. Well, I took mine home with me, and tried to charge it from the main line (not understanding chargers at the age of 10), but I was smart enough to know that the power straight from the mains was probably too high, so I inserted a resistor in the hot line. (I learned how to make a resistor explode). This was around 1969-1971 I believe.
nickademuss (author)  Goodhart5 years ago
hehe, when I was a kid, I grew up on a farm, now this farms power sucked, went off all the time. I took a shower one summer day, got out and was brushing my teeth when lightning struck a ran in on the power lines hit the well pump, followed the copper pipes to the bathroom and shot a huge spark from the faucet to the sink, mere inches away from some vital parts, as I was still naked. The worst shock i have gotten was off of a Hi-Pot machine that malfunctioned at work years ago, 15,000 volts knocked me across the room. My dad had a very hard hit when I was a kid, a concrete vibrator shorted out on him, he spent a few days in the hospital.
Yes, voltage at low frequencies and high amps is nothing to play with for sure.

Your lightning story reminded me of the time I was in Scouts (over 30 years ago) and was approaching one of the "Camp's" fancy outhouses. I was about 75 yards or so away when a bolt hit the outhouse. No fire was cause thankfully, but as I picked myself off the ground (just a knee jerk reaction of mine to hit the deck), out of the front door crawled a rather dazed but ok, fellow scout. The jolt had rattled him off the seat and dazed him enough that he was unaware that he had not "dressed" himself :-)
a couple of years ago my brother was working as an electrician and he was taking out these light sockets at some store, cant remember the details he said about it, anyways for nearly a week he said it never failed that he would get hit by 270 volts atleast once a day. Like i said im not sure the details about what he was removing, but i know he said it would knock him backwards.
the voltage with the potential amperage behind it can do some damage for sure. Thankfully he wasn't grabbing live lines with both hands...that is almost certain death. With my incident, it was two live lines, but it was on two parts of the same arm (if you have ever seen what that can do to a screw driver shaft DON'T TRY IT TO FIND OUT you know what it started to do to my arm.
Kaiven Goodhart4 years ago
I'm guessing... something like this? :)

We had an electronics instructor vaporize a # 2 phillips screwdriver discharging capacitors in a TV set one day.  I can imagine what happened to you!  OUCH!  Make that a triple ouch!
The whole class freaked when we heard it and saw a very bright flash go off.  You could hear other instructors cussin all the way down the hall for the EMP it created too!
I have a defibrillator that fires 34 joules directly into my heart.  That will ring your bell real good!  All your arteries become electrical conduits.  You see a blinding flash of light, feels like a horse kicked ya in the chest and head from inside, and yell loud enough to scare Godzilla.  Plus the full body contraction.  It has lit me up 12 times now saving my life from heart failure.  I pity anyone who gets hit hard.  5 in a row was enough for me.
Yes, well thankfully contact was brief and I wasn't sweating :-)  The "burns" were minimal;  the screaming was not  :-) 

I have done something similar to the high voltage input of the "gun" in the back of a tv tube, while it was live (plugged in), only it wasn't a screwdriver, but a HV multimeter probe (of which I now have a new one).  Wiped a roll of nearby film clean for sure (photo).

My father in law had one of those for awhile; but after a bunch of shocks that they determined were unneeded, it was removed and a simple pacemaker was installed.  Poor thing, he has Alzheimer's and couldn't understand why he was being electrocuted. *sigh*

i asked him and he said all of the lines were supposed to be dead, but some of them werent and every now and then he would clip a hot line, luckily he had 1000 volt tested electricians wire cutters(cant remember the proper name at the moment), but he still has them, and showed me where a hole was formed in them from it that ruined them.
Aye, that'll notch just about any conductive metal with enough resistance in it (steel, iron, etc)
I can say that 100kv from two igntion coils with 45 micro farad motor start caps pulsing at 100Hz hurts a lot.
Same here lol
Yes it is very nicely built. I worked at a plastics plant making bottles. We had a problem with the guys who recycled our used plastic we recycled back into the grinder machine. Nobody wanted to do the job, very strong charges built up in our half barrel 55 gallon drum that caught the hot plastic tails when the machine opened up and dumped the hot tails on the conveyer belt and dump into that barrel. Also, the 1000 pd. box of virgin plastic headed for the hopper would capacitate a nice charge too, but not as strong. It will throw a 6 inch spark easily. I got in trouble for wakin a dude up rudely lightin his rump up for goin to sleep on the job. I only got hit once by the big barrels when I took the job. About a 2 ft. arc hit me. My floor manager got hit with a bigger one and not all of the charge got past his tennis shoes to the ground. His feet felt like they were on fire he said. I told him not all of the charge penetrated your shoes. He asked, what do I do now? I said stay away from the machines, go to the bathroom and turn on the cold water. The entire plant heard him yell when what didn't get though his shoes arcs at the water line. Someone asked our electrical engineer what we can do about this problem, he said we can't do anything about it. I said BS, went out to my car, got some stranded 1 inch dia. aluminum wire I recycle, took about a 4ft piece, went to the shop, ground a point on one end, added more insulation to grasp, frayed the other end and added a pie pan to that end. Went back out and the big boss was still there, the engineer, drunk as usual, I stuck the contraption into the barrel and through a 2 ft arc at the machine. I looked at the engineer and BS we can't do anything about it, static energy 101 buddy!
Made him look like the fool, and my floor manager looked at me, leans over and says, don't let me catch you using that as a weapon in here. I smiled, and said, party pooper! I can't wake up the dead anymore?
nickademuss (author)  extrordinary14 years ago
cool story bro
I wish my stories were half as awesome as yours.
nickademuss (author)  extrordinary14 years ago
neet story thanks!
Johenix4 years ago
OKAY, who will be the first to make a 55 gallon plastic barrel into a Leyden jar?

About American power: Some call it 110v, others 120v, still others 115v or 117v AC 60 Hz (cycle) except for those places that might have 25Hz (Keokuck, Iowa and Ford Motor Company factories did) and those places where DC was optionally available (New York City until Con Edison shut down its DC service).

Lightning can cause the magnetic induction of a curent into a conductor. Some years back, I was walking near an unenergized power line undergoing renovation as a thunderstorm approached. I saw a flash of lightening and heard the 'Snap' of a large spark, and then a couple of seconds later heard the 'Crack' of thunder. This may be what some of the secondary lightening strikes are. 
Kryptonite4 years ago
You, sir, are an absolute legend. Very nice, 5/5 for craziness, well built and nicely written Instructable.
nickademuss (author)  Kryptonite4 years ago
LoL, Thanks!
bertzie4 years ago
Now if you could whip up a way to control the electricity inside, could use it like a giant battery!
finnrambo4 years ago
5 stars if a contest on voltage youll win
tried this and only got one nanofarad :P my wine bottle gets just the same with quite less mass however i did do a pretty sloppy job but still it was only bad enough to maybe half my capacitance
nickademuss (author)  The 4th Doctor4 years ago
With this device its more about getting allot of surface area to store a higher voltage. So just like a low voltage capacitor can store more amps and have a higher capacitance, this one is the inverses with lower capacitance and greater voltage.
well the surface area really is what determines the capacitance and the resistance between the two plates/strength of the dielectric determines the maximum voltage if you could get your hands on a multimeter capable of measuring capacity id like to know how much you got with yours since it is quite well done
dciocoiu4 years ago
You can charge the Leyden jar by using a Type 2 transformer the kind that you plug in the wall and that works if you have lots and lots of patients
lukkbox5 years ago
nickademuss - verb - meaning: humourless
Laminarin5 years ago
Have you measured the capacitance with a multi-tester? I'm not sure if it's possible to test with lower voltages with such a thick dielectric (plastic bucket) butI'd be interested to find out.
xirekaj5 years ago
I once made a leyden jar about the size of a popcan and ended up stopping my heart with it. If you arn't a very careful person I recommend using a film canister sized leyden jar as it wont kill you but is still pretty good if made properly.
nickademuss (author)  xirekaj5 years ago
I agree not for the careless here.....
Killa-X5 years ago
Someone correct me if im wrong. I was told by a person on my MSN who does a deal of HV, and he said it's stupid you made one that big. Because a small one will give the same spark length as a big one. Even though it's more surface area, that doesn't mean it stores higher volts, it simply stores the volts longer. Therefor you have the same visible spark output as a small one. Waste. is what he told me.
nickademuss (author)  Killa-X5 years ago
Its higher capacitance, and that does mean more AMPS in a discharge, I would be happy to let your friend touch it.
I can get 5 gal. buckets for free at my work XD
nickademuss (author)  Killa-X5 years ago
sweet! just make sure it doesn't have any scratches.
Well see, when your in high school, and the economy is bad, you get any job that's open. In my case, Bakery at a grocery store. So, I'm sure 5 gal buckets of buttercreme and dohnut icing wont be scratched all that bad really! I ended up telling my friend what u said, and he still said your wrong and that you only improve surface area, not amps. Just takes up more room.. lol.. I don't care personally. It's free so why not?
nickademuss (author)  Killa-X5 years ago
more surface area= more electrons stored, more electrons stored = more amps in a discharge, its not rocket science.

And it will KILL you if your not careful A VDG wont but a leyden jar of this size will. He can practice natural selection if he touches a fully charged one.

Back to free buckets, new ones like that would be perfect!
I hate to seem stupid but what is a VDG. It sounds like a social disease.
nickademuss (author)  stanley Knepper5 years ago
<a rel="nofollow" href="">Van De Graff Generator</a><br/>
gzusphish5 years ago
Could this be done with a plastic trash can? That would give much greater surface area. You could also line the outside of 8 buckets with foil and nest them. If the bottom one is bucket one and the top is bucket eight then you would need to connect buckets 1, 3, 5, and 7 to make one terminal and connect buckets 2, 4, 6, and 8 to make the other terminal. As mentioned in an earlier post, the problem here would be the connections introducing sharp edges where corona and arcing would be an issue at high voltages. Immersing the thing in mineral oil might help prevent corona from forming and leaching your charge. I don't know if that would help with premature internal arcing. One advantage of this arrangement is that instead of just using the inside faces of the foil, you are using both faces which I think would double the surface area for each layer except the outside ones. Or you could mimic a metal-film capacitor. Take 2 rolls of aluminum foil and unroll them. Place several layers of polyethylene or other heavy plastic tarp between them and several layers on top. These will be the two charge-holding surfaces. Instead of leaving them laying out flat though you can roll them up and drop them in a bucket. Before rolling make sure to run a conductor from the bottom layer so that it sticks out one end of the roll and another conductor from the top layer so that it sticks out the other end of the roll. Make sure also that the plastic film is several inches wider (6 inches on each side would be safe) than the foil. This will produce a cap with a phenomenally large surface area and will utilize both sides of each piece of foil instead of only one side as is the case with your leyden jar. It probably wouldn't be a bad idea to immerse this in mineral oil too. It also would probably be helpful to roll the thing onto a piece of PVC pipe as this would make it easier to start the roll and also give you a hollow core to help with securing it somewhere. Sorry for all the unsolicited just got me thinking.
Benjamin Franklin once almost killed himself when he backed into a Gallon (4 Litre) size Leyden jar. A 50 gallon garbage can Leyden jar would probably kill an elephant!
If you really wanted to be dangerous, build a large induction coil like they used to do in the mid-1800's for public demonstrations of electricity. That's what they did when they got bored with low-current electrostatics. But who has miles of copper wire ...
BTW...These ideas are off the top of my head and untested. If they are bad ideas or otherwise theoretically unsound someone please call me out.
nickademuss (author)  gzusphish5 years ago
Oh I forgot, when making a static electricity capacitor, even mineral oil will drain it off very fast, remember this is designed to store more voltage with a trade off of lower current. its only 0.0008 uF
nickademuss (author)  gzusphish5 years ago
I like idea's, nesting them might work, it needs to be internal hooked up in parallel, very hard to do without the charge jumping around inside. The trashcan would work best i think, You just have to leave allot of exsposed plastic on the top, it keeps the spark from jumping. A coiled up one like the dielectric type would also be hard, you need precisely the same surface area on the negative side as the positive. You may be able to contain it in a bucket but not use the outside of the bucket. Im sure your designs would hold a charge though, just not sure how much of one. This one takes a few hours to make, I have seen smaller ones on the net used in parallel he just has all the wires insulated in PVC pipe, and the spark was huge!
EnigmaMax5 years ago
it would be great spook alley prop.
strangebike5 years ago
Nice job looks the business. Is there anyway of resisting the flow of the charge to make it last longer or be less fatal ? Probably a dozey comment but I have no experience with this sort of thing and am just curious.
nickademuss (author)  strangebike5 years ago
Na, this is built for max danger or bigger sparks...
macrumpton5 years ago
Great project! I wonder if you could use a metallic or conductive paint instead of the foil? i
toddjwood5 years ago
Great Instructable,
A note on voltage
The maximum voltage will almost never exceed the output voltage of the VDG, because a capacitor can only be charged to the input voltage. However, the faraday Ice pail effect would allow for higher voltages and as the charge is being applied to the interior of the bucket you could obtain a higher voltage. But losses in dielectric leakage and the small output terminal would most likely decrease this.
I have built several of these and have found aluminum flashing easier to work with, I first wrap the bucket with paper and angle it so that it lies flat against the bucket, tape it to hold it in place and then use a razor to cut around the bucket. When unwrapped you have an arced strip to use as a template for the inner and outer surface. I then use aluminum tape to secure these to the bucket. I don't cover the entire bottom of the bucket as it is actually thinner on the bottom then the sides. I just use a strip behind the inner layer and under the outer layer to make contact with the output rod and a convenient ground source.
One note of caution take a heavy gauge wire with clips on each end and keep it connected to the output rod and the outer plate when not in use, especially if it is anywhere near the VDG as its electric field can extend much further than can be felt and you do not need a physical connection to the VDG to charge the leyden Jar. I have gotten a shock from mine when cleaning the outside, it apparently induced a charge on the outer plate and in turn on the inner one. The charge was strong enough to hurt but not to do any real damage. Lesson learned, keep it grounded when not in use. Too late is Too Late!!
puffyfluff5 years ago
While you can store a sizeable charge on this cap, the voltage will be somewhat limited by the dielectric strength of the bucket and of the air between the two capacitor terminals, and by the radius of the floating terminal, just as the radius of the ball on the Van de Graaf generator limits its voltage.

As charge builds on the ball the E field at the surface of the ball will exceed the breakdown voltage of air and the charge will leak off, thus limiting the voltage that can be achieved. The smaller the radius of the ball, the less charge is required to reach the breakdown voltage.

The energy stored in a capacitor is 1/2 * C * V2. If you use a larger radius terminal and maybe insulate the bucket a bit better you can dramatically increase the energy stored. Even as you lower the capacitance by adding insulation the total energy storage will rise because the energy storage increases as the square of the voltage. Doubling the voltage increases the energy stored by 4X. You can increase capacitance by increasing surface area- i.e. size of the capacitor.
nickademuss (author)  Mark Rehorst5 years ago
Adding insulation as in making the bucket thicker? or insulating the center post? And the door knob is all I had laying around for the center terminal, Should I put something say as small as a 3/4" ball on it? and should I insulate the center post with say some PVC pipe? Thanks for a great post BTW!
The photos of megavolt Van de Graff generators you see all have gigantic spheres to keep the charge density of the surface of the sphere from producing an E field that exceeds the breakdown voltage of the air. Putting a bigger ball on it- like one that matches the Van de Graaf generator would raise the voltage on the capacitor. Yes, making the bucket thicker (using the right electrical insulating material) would raise its breakdown voltage but would reduce the capacitance and thus the energy stored. A combination of insulating and increasing the surface area would allow you to maintain or even increase the capacitance.
nickademuss (author)  Mark Rehorst5 years ago
Ore two or more of these in parallel !!! hmm now were did I put that other bucket? Twice the capacitance, I can also use off the shelf copper plumbing parts to link the two center posts and set the buckets on two copper pipes.... would take twice the recharge time..... LOL
Why not use a large diameter piece of ABS or PVC pipe (whichever has greater dielectric strength) and use a single, large ball terminal? If you try connecting multiple units together you have a hard time preventing corona discharge that will rob you of storage capacity. The smallest metal radius is going to be where the field is most concentrated. The smallest radius piece of metal such as wire or even copper pipe connecting two caps together will be the source of corona discharge.
nickademuss (author)  Mark Rehorst5 years ago
So a 6" sphere from my small vdg would rock, ill try that!
Oops. That exponent got me!
Could you use this as an normal capacitor for like mains filtering for example??
No, mains filtering requires much larger capacities than this leiden jar has.
can u charge it without a vdg
nickademuss (author)  imthatguy11255 years ago
Yes, anything that generates static will let you charge it, even a plastic pipe and a piece of wool, but it will take along time to charge it that way, a disk type machine like a Whimshurst.
mikedoth5 years ago
What kind of voltage can be achieved by this?
nickademuss (author)  mikedoth5 years ago
Its a capacitor of around 0.0008 Microfarrads. It will take the charge you give it, not build upon it. If you charge it with 900,000 volts thats how much it will have, but because you can store more electrons than the power source can put out all at once, the Leyden jar puts out more current, allot more!
Is it possible to drain the current slowly from a source that big?
nickademuss (author)  mikedoth5 years ago
how slowly?
Slow enough to run something like a light off of it in case of an emergency.
if you want to use capacitors than you could use super capacitors they are low voltage but but high capacitance. the largest I have seen is 5000 farrads and they will take about one million charges compared with a few hundred with batteries.
yes but that is probably a 2 volt or less capacitor, completely useless
nickademuss (author)  mikedoth5 years ago
im afraid no matter how you hook it up its going to discharge to fast and most likely blow up any device. My advice is to use rechargeable batteries and LED bulbs, much safer (:
I had a feeling, thanks for the quick replies!
8bit mikedoth5 years ago
Through a resistor
nickademuss (author)  8bit5 years ago
have to be one hell of a resistor! it already sparks a distance larger than most commercially available resistors.
How many volts can it handle?
nickademuss (author)  8bit5 years ago
From what I have researched the voltage in in the "giga" range but current is limited, building several and hooking them up in parallel will boost current, that would mean a long charge time from your VDG as well. Remember this is an experiment in progress, I cant find anyone who built one like this, so after I get a test rig built that will peak the voltage and spark length, I will post the results, ETA a few weeks....
8bit 8bit5 years ago
And for that idea, how much power can it put out?
FaqMan5 years ago
Look at the electricity go up.
J-Five5 years ago
It's Alive!!!
make sure the bucket is new and has no scratches or cuts in it or it wont work. I tried this before and my bucket had a scratch in it and it just arced through the bucket
nickademuss (author)  rocketman2215 years ago
good advice! I used a almost new bucket, and did inspect for damages.
buirv5 years ago
That's not a jar of doom. It's a Leyden Jar from Hell! Awesome. How much will that through out? You'd probably get clobbered by it if it's charged. Have you tried making one out of a plastic Garbage Can? That'll be the "Leyden jar from Hell and Back" LOL B-)
nickademuss (author)  buirv5 years ago
not sure of the peak output I have only begun to test it, I did post a vid, it sounds like a shot gun going off when it sparks. It will make your ears ring thats for sure. I plan on building a better test stand and better grounding for it, it can do better.
Kiteman5 years ago
acaz93 Kiteman5 years ago
nickademuss (author)  acaz935 years ago
well you could say that, lol

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