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Leyden jar

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Electronman

New Member
Hello,

I would like to make one but have no access the very high voltages (just have a 30V DC power source).
I have read that we can use the static electricity from PC's and TV's monitors. Is that true? How to use it?

Besides I want to make one because they are fun, But do they have any practical usage?

Thanks.
 

Sceadwian

Banned
Put a sheet of tin foil over a CRT screen while it's operating. Instance very low current high voltage source. Problem is there's a decent AC component as well.
I've not seen too many practical uses for anything that would actually require a layden jar, perhaps an electrostatic separator.
 

EN0

Member
Take a plastic film canister and wrap aluminum foil on the outside and also on the inside. Then have two wires coming from both aluminum foils and you have a leyden jar capacitor.
 

Electronman

New Member
How to connect the Tin foil to the capacitor? Via one wire to the central nail or..?
What's an electrostatic separator?
 

Electronman

New Member
Take a plastic film canister and wrap aluminum foil on the outside and also on the inside. Then have two wires coming from both aluminum foils and you have a leyden jar capacitor.

But I thought I can use Water as inside plate???
If so how does the water acts as inside PLATE? any free ion or..?
 

EN0

Member
The idea is to make a capacitor, right? Well a capacitor consists of two conductive plates with a dielectric in between; depending on the permittivity of the dielectric and the proximity of the metal plates. Those variables determine the output capacitance. The dielectric for my suggestion would be the plastic canister. The metal plates would be the aluminum foil on each side. You could use water for the inner cap layer but It wouldn't work very well. I would use a more conductive material. Take a look at this:

leyden jar
 

Sceadwian

Banned
Leydan jars if used modernly are pretty much exclusivly used in HV capacitors. Foil inside, foil outside, bam capacitor, very very high voltage ability, but because the glass is thick very low capacitance. It might help if you explained what you were trying to do so we could help you with the appropriate way to approach the problem.
 

Electronman

New Member
I just want to show several of guys how a capacitor does work and show them the first older caps.

My Jar has a capacity of 1.3nF, but I do not know how to connect it to my TV screen? I was not able to produce any arc when I tried to put a metallic foil near the TV screen And connect it to the center screw of the jar?! What to do with the other Plate connection while charging the cap?
 

EN0

Member
I built a leyden jar capacitor and when I put it near a slide full of static electricity, it literally "jumped" into the cap. So just run the cap over the TV screen within close enough proximity and you should hear a crackling noise; that means the cap is charging.
 

Electronman

New Member
I built a leyden jar capacitor and when I put it near a slide full of static electricity, it literally "jumped" into the cap. So just run the cap over the TV screen within close enough proximity and you should hear a crackling noise; that means the cap is charging.

Can you explain what did you do really? My poor English prevented me to clearly understand you. What did you do for the outside connector when you wanted to charge it? Could you see any arc after charging?
 

EN0

Member
All you have to do is put the leyden jar capacitor (that you made) and put it close to the TV. You will hear this popping noise when you do that and that means the cap is charging up the static electricity generated from the TV screen. Just simply run it over the TV screen all around it. Then all you have to do is touch the positive ternimal on your cap (the inner layer of aluminum foil) and you'll get a minor shock.
 

Sceadwian

Banned
Take a sheet of tin foil, cover the entire front of the TV screen with it, connect it with a wire to your layden jar holding it with something isolated get the other end near ground. If the capactiance is high enough you should see an arc, if it's not you won't. Think of the sheet of tin foil forming a capacitor with the inside of the TV tube.

A good source of high voltage is plasma globes, those I know work great, near dangerous territory actually. I have a small 3 inch one that will give you a good wakeup, and the neighbors have an 8 inch one that if they foil is more than about 3 inches square is enough to cause punch in the face kind of pain, moderate arcs.
 
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