Instructables
Picture of Jacob's Ladder
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A Mad Scientist laboratory is not complete without a Jacob's Ladder. If you have always wanted one as a prop for Halloween or just to display, then this instructable will show you how to build one. It is very simple to make and you only need two components to make it happen.

Please vote for me for the Halloween Decorations contest.
 
 

If you wanted to know why the arc ends up going vertical instead of staying at the same spot, here's an explanation from Wikipedia.

"When high voltage is applied to the gap, a spark forms across the bottom of the wires where they are nearest each other, rapidly changing to an electric arc. Air breaks down at about 30 kV/cm,[2] depending on humidity, temperature, etc. Apart from the anode and cathode voltage drops, the arc behaves almost as a short circuit, drawing as much current as the electrical power supply can deliver, and the heavy load dramatically reduces the voltage across the gap.
The heated ionized air rises, carrying the current path with it. As the trail of ionization gets longer, it becomes more and more unstable, finally breaking. The voltage across the electrodes then rises and the spark re-forms at the bottom of the device."




This Instructable involves the use of High Voltage and if you are not careful, you will be seriously injured or killed! If you are not familiar with working with High Voltage, please DO NOT attempt until you research it and take all necessary safety precautions.

Make sure to keep it away from everyone that views it by placing it in a clear housing or placing it in an area where it can be viewed and NOT touched. 
We place ours on the roof of a treehouse during Halloween so that its away from everyone that comes through our haunted yard.   


 
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I have access to several different "ratings" of neon sign transformers. Are there any that cannot work for this or that are not recommended? Or is it ok to use whatever?
just curious.

thanks
hackmattr (author)  ghostbiker131 year ago
Smaller transformers may not have enough power to create a good jacob's ladder. Higher voltage is better.
dlemke1 year ago
I like the idea of using copper for the colors, but you can also use a lighter guage wire for smaller transformers and greater movement on the big ones. I have used the wire from marking flags you see along the road to mark buried utilities and stuff and you can buy them at a farm supply store for about 10.00 for 100 or so markers. get the longest ones, as they are usually the same price, and the wire can be used for many, many projects, as it is a very stiff wire that can be used for linkages, etc.

When the thinner guage wire is used on your ladder, the wires will move in and out more and give you more or different movement of the arc's.

Dan
denpag1 year ago
Also, if you substitute the two wires, use one brass gas welding rod for one side and one copper coat gas welding rod for the other side. You will get a green blue spark. Still use plenty of ventilation. Avoid at all cost, getting too close. I prefer using the 12-15kv neon sign transformers my self. The 15ma ones work great. 30ma is better, but the cost goes up significantly. I used to use these and tesla coils in a haunted house for halloween. Another fun project that I might put on here later, using flourescent tubes, you can have ribs of light moving up and down the tubes.
Woow, looks great, nice job!
Aleator7771 year ago
I never get tired of seeing these. Thanks for the instructable!
XTL1 year ago
Please swap coathangers for aluminium or steel wire. Regular coathangers are often zinc plated.
The sparking will release zinc oxide particles. Breathing them is not so good for you.
The zinc shakes is a problem for people welding galvanised steel.
http://en.wikipedia.org/wiki/Zinc_shakes
http://en.wikipedia.org/wiki/Zinc_toxicity
Set2711 year ago
Also be aware that sparks create ozone. If you plan on leaving it on for extended periods ensure there is plenty of ventilation.

http://en.wikipedia.org/wiki/Ozone

If the case that encloses the transformer is ventilated that too creates ozone of a smaller magnitude. High voltage magnetic fields create ozone.

http://news.bbc.co.uk/2/hi/health/3472383.stm

Don't mean to be a buzzkill...it's just research I've done in the past.
hackmattr (author)  Set2711 year ago
Yea. I forgot to add that about ozone. It can also cause radio interference.
Always wanted to build one of those, but suitable Transformers seem hard to come by here in the UK. You would not BELIEVE the prices the neon sign people want to suck out of your bank account to let you walk away with their junk.

One might almost think I wanted their PERSONAL "Junk".

I'm not an expert on Oil Burning heaters either, but since they don't seem to need extinguishing and relighting (not sure if that's a requirement here) they don't seem to have big transformers either.

It should be possible to do with a modified Microwave transformer, but I'm not sure I'd know exactly how to go about it.
hackmattr (author)  Dream Dragon1 year ago
You can check ebay, electronic surplus, electronic supply, and appliance supply stores too.

If you can't find one from those sources, you can always build a transformer yourself. This video on youtube was done by some guy in Colombia so the English is off, but it gets the point across.

http://www.youtube.com/watch?v=s6NyTprQCBI

Just remember to make a step up transformer. I think the video shows a step down transformer.


Microwave oven transformers can be used, but I would not use them because they are very unsafe. This site explains how to build them and what components should be used. http://www.repairfaq.org/sam/jacobs.htm#jlwnm
Krayzi991 year ago
used to make tons of these with my dad, still great to see!
seraine1 year ago
Rimar2000 has a great way to straighten wire. http://www.instructables.com/id/An-easy,-cheap-and-efficient-way-to-straighten-and/
hackmattr (author)  seraine1 year ago
Thats a really good idea. I've used it to make a wiring harness, but never thought to do that with it.
Gelfling61 year ago
Besides a Neon Sign power supply, you can also do this with a ignition transformer from an old oil-burner from a furnace. Many years ago, we had one fail on our furnace, and the tech who came to service it, said he had seen others do it with old ones.. the gap need be about 3/4 of an inch apart at the bottom, and can extend outward to about 4 inches, as high as 3-feet _\ /_ style wires.
As with ANYTHING with voltages above 60V, take great care never to make contact with the output of the transformer, or the wires, or results could be FATAL! (this coming from receiving a good 8KV shock across my arm.. swung around, and it knocked me to the floor! I was just plain lucky!!!)