Make a Water Leyden Jar




About: ––––––––––––––––––––––– "Energy cannot be created nor destroy...

Here is another type of high voltage capacitors - a Salt Water Leyden Jar!

Don't know what a leyden jar is? No worries! Read here on Wikipedia!

The water leyden jar is easier to make than a normal leyden jar because putting foil tape perfectly on the inside of the container can be very difficult. If the foil tape job is messy, it can cause a lot of corona discharge, therefor draining its charge very quickly. So instead of having a hard time of perfectly putting foil tape on the inside of the container, just simply pour salted water in!

The leyden jar is a high voltage capacitor, high voltage capacitors are one of the most dangerous things you could ever use in electronics. A large charged leyden jar is potentially lethal if you touch its live terminals, and a small charged leyden jar can cause injury and it still be lethal in some ways.
So, I am not responsible what ever you do with this information and leyden jars.

Step 1: Get the Things!!

Okay, what you will need is...

  • Plastic or glass container
  • Water
  • Salt
  • Stainless steel nail
  • Aluminum foil (or even better, use AL foil tape if you have any!)
  • Tape (you won't need it if you are going to use foil tape)

Step 2: And the Tools...

Not many tools are needed to make a Leyden Jar.

  • Hammer
  • Hot glue (or anything to seal up the container to prevent water coming out)

I think that is just about it.

Step 3: Take the Sticky Stuff Off!

Before we start making a Leyden Jar, take all of that sticky stuff off! It can reduce the performance of the Leyden Jar, or even cause problems if you don't take the sticky tags off!

Step 4: The Construction of the Leyden Jar Begins...

Cut out a narrow sheet of foil about a centimeter or two shorter than the jar. Then wrap the foil around the jar, I used tape to hold the foil onto the jar. You can use glue if you want, but don't use flammable glue because of sparks, it is likely to catch on fire. There has been a report a leyden jar had exploded because the creator used flammable glue on the inside of the leyden jar.
After you wrapped the jar with foil, put some more tape on the top and the bottom of the jar to give the foil more protection from damage.

You can use something much much better than foil, use foil tape. You can just simply tape around the jar and not have a hard time wrapping the jar with foil and tape (or glue).

Step 5: The Wet and Salty Part...

Fill the jar with warm tap water. Then add a few teaspoons of table salt, and stir well!
After that, put the lid of the jar back on! Now it is a Leyden Jar!! (Well, almost.)

Step 6: Hammer in the Nail!


Hammer in the nail in the center of the lid, and leave the head of the nail about a centimeter away from the lid.

Step 7: Seal It.

After that, put some hot glue around the nail and the lid to stop the water coming out.

Step 8: Mission Almost Completed...

Attach a piece wire to the foil of the leyden jar.

Step 9: Completed!

There! You made a salted water leyden jar!

I also added a magnet and a ball to make it more "Leyden Jar" like.

I measured the capacitance of my leyden jar, and my meter reads 946pF, that is about 1nF! that is quite high for this small leyden jar!

Step 10: What to Use It For.

If you want to electrostaticly charge your Leyden Jar, read this site, it will show you how to make a simplest charger you can ever make.

Or even far more dangerous, treat it as a normal high voltage capacitor, you can use it as a capacitor bank for the tesla coil, or something like that.
I tested my leyden jar with high voltage power supply to see if it works. Never ever do that, unless you have good experiences with high voltage.

Step 11: My Set Up.

That is not my only leyden jar I made, I made many more, even leyden jars made out of wine bottles, but they did not turn out right, so, I threw them out..

I used my high voltage power supply (flyback transformer driver) to test the leyden jar I made, it works very well, and makes very bright sparks! I could probably use this as a Tesla Coil capacitor bank..

Well, I hoped you enjoyed this instructable!
If you have any questions, or need help, or found an error, or anything, make a comment! I like comments! :)

Second Prize in the
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Participated in the
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2 People Made This Project!


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563 Discussions


25 days ago

My boyfriend has been trying to build a leyden jar using plastic container with a plastic lid. He can never seem to get the foil even, and wrapping it neatly. He always has the foil over lapping each other unevenly. He is tired of wasting aluminium foil trying to make it. Any other way of getting the foil strait? Please send any new ideas. Thanks.


Question 1 year ago

is it a polarized capacitor or non polarized.

nice work


1 year ago

it can be made without water also


2 years ago

What I would like to know how can you calculate the capacitance? Haven't got a meter.


2 years ago

Hi, this is a really detailed instructable! I'd like to ask:

Could you please detail the way you charged up the jar? The link you've attached doesn't seem to be working. It'd be great to find a method where the charge is roughly the same every time.

How can you safely disassemble this without getting a shock? It seems dangerous to simply throw the whole thing away.

Any help would be much appreciated! Thanks so much

1 reply

Reply 2 years ago

Just take a short piece of insulated wire and touch the nail and the outer foil at the same time. It is then discharged. You can repeat just to make sure


2 years ago

Static is over a million volts. You could have 1,000,000,000,000,000 volts and 0.5 amps and you would not die.

2 replies

Reply 2 years ago

0.5 amps at THAT voltage is lethal. You should go to micro amperes.


Reply 2 years ago

i don't know about that, 0.5A is quite a lot at those kinds of voltages. i think you'd probably have to go down to less than 10mA at 10^(15) volts to survive.

but i'm no pro. so who knows.


6 years ago on Introduction

It's Actually The Amperes That Kill Not Volts I Have Taken A Nasty Shock By A Million Volt Stun Gun

4 replies

Reply 4 years ago on Introduction

it is a combination of amps and volts that are able to kill. you have to have enough voltage that the charge is able to make it through the resistance of your body(skin. etc) but once you over that voltage (no, i dont know the exact value, it probably varies a lot) the amps do damage. in the future please dont make such a "blanket response" as it is a combination fo many factor that determine fatality. IN TheKingOfRandom's youtube channel there is a video where he grabs onto the live ends of a modified microwave oven transformer, he brought the voltage down to just 3 volt with it and although there was lots of amperage (he used it to weld steel washers) there wasnt enough voltage to go through the skin.

(I nearly killed myself while taking apart a 60cm crt tv that was just plugged in. i cut the cord going to the cathode ray tube and was knocked against the wall and temperarily blacked out.... fun..)


Reply 3 years ago on Introduction

I have always found this whole argument to be extremely ignorant...yet I see it everywhere. All you have to do
is look at ohm's law (V=IR) to realize that Voltage, current, and
resistance are related. Current, resistance, and voltage, it turns out,
are all just different aspects of the same thing--the flow of charge (or lack thereof) across a difference in potential. If you doubt this, set any of the values to zero and see what happens.
This is not enough information. It IS the flow of charge that causes burning and "clenching", but
that's only part of the picture. Next, you have to think about current
density (or energy) because a heat is easier displaced by larger objects across greater surface areas
and it's a concentration of heat that burns. Finally, we must think about the speed at
which that energy is displaced, or power. A
large, quick burst of energy does more damage than a smaller flow over a
longer period of time, even though the same amount of energy is
displaced. Again, heat is dissipated as it is being added as a function of In truth, it's not potential OR current that kills. It's not even energy, it's POWER.
Ohms don't kill, Voltage doesn't kill, and neither do Joules, WATTS KILL. Now all of this was somewhat over-simplified, but you should get the idea. There ARE other things
that come into play, too. Some organs are more susceptible to damage than
others. There are also differences between the way AC and DC affect
different parts of the body. Both of these make both the type of
electricity, the path it takes through the body, the frequency (if AC),
and the phase of that frequency with the heart and other bits (also for
AC only), and others but it is the power of the zap that does it, not
simply the potential or the current.


Reply 2 years ago

It depends on AC or DC but I always think 35V just to be safe as I use AC quite often and the rule is about 50VAC. Just don't touch wires and you'll be fine lol


3 years ago

Hi there!

Great instructible, but I'm wondering if there is any problem with using a glass jar with a metal lid? I can't see it causing any problem since the electrode is going to be touching the water and the glass is a good insulator but I though I should ask! Thanks!


3 years ago

How long will a charge last in a reasonably well-built jar? Batteries will slowly drain over time. I assume these do too?

2 replies

Reply 3 years ago

If you live anywhere that is ever humid (even deserts are humid at night) then there will be high leakage, you need a very dry environment for static experiments to work well.