Simple Leyden Jar




Introduction: Simple Leyden Jar

About: Science is my passion. I find myself constantly working on countless experiments, from low energy particle accelerators to good old simple electronics. I also like making model rockets, and playing cello.

So I needed something to procrastinate from homework with one day, so I decided I would make this leyden jar. I had all of the materials laying around (as do most people) and about ten minutes I didn't want to spend doing homework, so this was perfect. the design is pretty straight forward, so I will not go into a whole lot of detail. Either way, this is a perfect beginning electronics project for anyone. I do not think there is really anybody who is not capable of making this. 

Step 1: Construction

Leyden jars have been around since the late1700s. They are basically a primitive capacitor. it holds charge and will discharge.
In this jar there are five main parts. the inside foil, the outside foil, the inside wire, the outside wire, and the jar itself which must be an insulator. basically if you build up a positive potential in the inside foil, and keep the outside foil grounded, it will want to make the charge on the outside equal that of the inside, so a spark will jump from the grounded outside to the inside.
      To make it all you need to do is glue some aluminum foil to the outside of the jar (which needs to be glass or plastic), and tape a wire to it, glue some more foil into the inside and tape some wire to that. drill a hole in the lid of the jar and put the wire connected to the inside through it. screw on the lid and you are done.

Step 2: Charging

Once you have your leyden jar made, you need some way of charging it. You could connect the wire to the inside foil to a van de graaff generator, but if you are like me, you do not have a van de graaff generator, or any other kind of electrostatic generator. One way you could charge it that works okay, is turning on a CRT TV/ CRT computer monitor, waiting for it to light up completely, and then turning it off and stroking the screen with the wire leading to the inside foil. when you touch the inside wire to the outside wire, you should see a small spark. The way I found to work the best, is to actually simply walk across carpet wearing socks, and build up static electricity that way. All you need to do is hold onto the outside foil while you do this, and keep the striped parts of the wires close to each other. Once you build up a large enough charge, your jar will discharge from one wire to the other. I have gotten sparks up to about 3 or 4 mm. long doing this. What I love about this method of charging, is that it doesn't require the buying or making of a generator. If you make this please tell me how it works, and possible improvements I could make. Have fun!



    • Fix It! Contest

      Fix It! Contest
    • Metalworking Contest

      Metalworking Contest
    • Creative Misuse Contest

      Creative Misuse Contest

    8 Discussions

    I have never been able to charge a Leyden Jar. Any suggestions?

    Could I charge it with an AC generator????? I have a hand-crank AC generator out of an old telephone and I was wondering if it would work with that.

    great idea.i made one and its so easy.just charging is a little challenge.except that every thing is easy

    1 reply

    Thanks! I was actually kind of surprised by this, but simply walking on carpet while holding the outside foil can create enough static electricity to charge the jar. This only works in low humidity of course... You can also stroke the wire from the inside foil on a CRT TV or monitor to charge it, or use a van de graaff generator (like the one I made or a wimhurst machine to charge it.

    You could, but you would want some distance between the outside foil and the lid, which would depend on how big of sparks you would be expecting to make. I would make the distance double what you expect to make.

    I heard that copper wire doesn't work for this.

    Have you done it with copper wire?

    1 reply