What is Leyden jar: Definition and 15 Discussions

A Leyden jar (or Leiden jar or Kleistian jar) is an electrical component which stores a high-voltage electric charge (from an external source) between electrical conductors on the inside and outside of a glass jar. It typically consists of a glass jar with metal foil cemented to the inside and the outside surfaces, and a metal terminal projecting vertically through the jar lid to make contact with the inner foil. It was the original form of the capacitor (also called condenser).Its invention was a discovery made independently by German cleric Ewald Georg von Kleist on 11 October 1745 and by Dutch scientist Pieter van Musschenbroek of Leiden (Leyden) in 1745–1746. The invention was named after the city.
The Leyden jar was used to conduct many early experiments in electricity, and its discovery was of fundamental importance in the study of electrostatics. It was the first means of accumulating and preserving electric charge in large quantities that could be discharged at the experimenter's will, thus overcoming a significant limit to early research into electrical conduction. Leyden jars are still used in education to demonstrate the principles of electrostatics.

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  1. gregory112

    Troubleshooting a homemade Van de Graaff machine

    I'm trying to build a Van de Graaff generator, but it does not generate any charges. The problem is, I don't know which part is accidentally shorted, or grounded. I use both PVC pipes for the top and bottom rollers. The belt is neoprene rubber, 1mm thick. The rollers are bolted on aluminum...
  2. C

    How Do You Build a Functional Leyden Jar for a School Project?

    I'm a high school junior and doing a project on ben franklin. specifically I'm making a model of his electric motor which used two Leyden jars to operate. I want to make it a working model but I cannot get the leyden jars work. can anyone explain to me how to construct a historically accurate...
  3. I

    I Leyden Jars increase spark length?

    Good Evening/Morning/Afternoon Everyone, Question: Why is it that demonstrations of Van de Graff generators use Leyden Jars in series to get bigger sparks? If a spark gap's size determined by voltage, and Leyden jars are simply to be treated as capacitors which wouldn't increase voltage, why...
  4. I

    Generating High Voltage: Safe and Effective Methods for Amateur Use

    Good Afternoon everyone, Question: What are some effective ways to generate a high voltage (Multiple KV) using amateur equipment? I've dealt with high voltage before, so I'm aware of the safety issues. Anyway, here is what I've got thus far: If you go on ebay, and search for high voltage power...
  5. B

    Calculating the ratio of charges in Leyden Jar

    Hello In Walter Lewin's lecture while explaining the Leyden jar he says that the charge on the glass is 12 times more than that in the air gap. How is this obtained ? Basically there are 2 metal containers separated by a glass sheet. The air gap between the outer conductor and glass is 1...
  6. J

    What is the resulting amperage from a Leyden jar discharge?

    I need to figure out how to correctly calculate the Current being created from a leyden jar I have. I am attaching a print screen of a matchcad calculation that shows what I have done. However, I am calculating extremely high amperage. I believe my calculation is correct down to my charge, but I...
  7. W

    Leyden Jar - 2 bottles - 1 positive 1 negative?

    I never could get leyden jars to work. I'm trying to use a few 3 liter bottles I have here at home. I also have quite a few solar panels and other materials like aluminum foil and copper. I was thinking today that it seems it would be easier to have 2 bottles, 1 with a copper lead dipping...
  8. F

    Will a Leyden Jar Store AC Current?

    Okay, I was planning on building a Tesla coil for my (high school) physics class. For the high voltage capacitor I was planning on using a Leyden jar, however, after doing some research I only found references to it being used to store an electrostatic charge. Thus, my question is, can a...
  9. C

    Van de Graaff + Leyden jar a dangerous demo?

    Hello all, In my first high school physics class my teacher performed an incredible demo that has stuck in my mind ever since. After playing around with a Van de Graaff generator a bit he whipped out one of those homemade plastic bottle and aluminum foil Leyden jars and charged it up using...
  10. miraiw

    Is my Leyden jar experiment properly designed?

    I'm attempting to make a Leyden jar by taking a plastic cup, covering the inside with aluminium foil, and then filling the cup with salt water. I have a spring sticking through the centre that conducts through the inner foil. Judging from the Wikipedia article on Leyden jars I can use my hand...
  11. C

    Is the Leyden Jar still charged even after discharging the metal parts?

    A couple of questions about the leyden jar . When i first charge up the leyden charge with a potential difference and then i dissemble the jar and i touch the metal parts of the jar to discharge them , Am i ionizing the copper that the jar is made of , And question #2 let's say I...
  12. M

    Leyden Jar Help: Using Spray Adhesive on Foil Layer

    im making a large leyden jar to be charged from a van der gaaf generator. does anyone know if i use spray adhesive on inner foil layer to hold it in place will it affect the way it works? or stop it working?
  13. W

    First Leyden Jar - experimenting.

    I have just built a saltwater Leyden jar from a drink bottle and foil and am genuinely joyed that it produces a spark after charging from the TV screen. Good Fun. So I understand that the charge lies on the interfaces between jar/foil and jar/saltwater. Then I googled "saltwater capacitor"...
  14. S

    Leyden Jar Capacitor Recharging?

    I built a leyden jar and have noticed something rather interesting: After discharging the jar and letting it sit overnight I can come back to it and short it out and get a tiny little spark...then I let it sit and come back later and I can get it to spark again. I've repeated this over and...
  15. C

    Charge in an Isolated Leyden Jar: Will it Spread?

    Imagine an isolated cilindrical Leyden jar. A Leyden jar is something like a big capacitor, and normally, the external plate is grounded as we charge. But now, imagine this Leyden jar is not grounded, and you go charging the external plate. Finally, you'll have excess charge on the...