Homemade Leyden Jar Capacitor

[Tommey Reed]

Hi all,

Leyden jar capacitor are one of the simple build around when is deal with capacitors.

https://www.youtube.com/watch?v=YpjY4TcilyY&list=UUSonN_EWtb4Dhq2r9WC6mFQ

Tom

[the_big_m_in_ok]

Hi all,

Leyden jar capacitor are one of the simple build around when is deal with capacitors.

https://www.youtube.com/watch?v=YpjY4TcilyY&list=UUSonN_EWtb4Dhq2r9WC6mFQ

Tom

I tried to invoke the Reply with a mouse click, and there's an error message that the Youtube video was deleted.   Do you have an alternate one?
--Lee

[TinselKoala]

TR periodically deletes his videos, it seems. But there are many YT videos on the topic of Leyden jars.

Myself, I don't mess with them because I have dozens of 400 pF 30kV strontium titanate dielectric "doorknob" capacitors that are far better in most ways. They are much easier to work with, but you can make Leyden jars for essentially nothing out of scrap recyclable plastic bottles or buckets or whatever, whereas the doorknob caps can be expensive if you look for them on Ebay. I got mine for very cheap though, which is why I have so many.


I know you are disappointed because Tommey's video is gone, so I'll post one of mine for your amusement.

http://www.youtube.com/watch?v=vBFopZNF5iM

[Verpies]

Myself, I don't mess with them because I have dozens of 400 pF 30kV strontium titanate dielectric "doorknob" capacitors that are far better in most ways.

How do capacities and voltage ratings of Leyden jars compare ?

[TinselKoala]

Well, it depends on the material and dimensions of the Leyden jar, of course. In the old days you'd say that they had "one jar" of capacitance. Wiki says for a "typical" one pint jar it is about 1 nF, but the voltage will depend on the thickness and material of the jar wall. For something like a polycarbonate beverage bottle it is probably around 5 kV or so. So a small parallel stack of the doorknobs I have would be superior in voltage and easy to make equivalent in capacity to a "typical" jar. The doorknobs have female-threaded terminals so it's easy to daisy-chain them with headless screws and to make connections to the ends.

[chief kolbacict]

If we take a disk capacitor, drill a hole in it and put it in place of the accelerating electrode in the CRT. We apply a plus to the plate from the cathode side, and a minus to the opposite side. The electron is attracted and accelerated to our improvised electrode. Then it flies through the hole, and then is repelled, accelerating. Will the energy of the electric field be spent on accelerating the beam, in other words, will it be necessary to constantly recharge our capacitor ?