This instructable will show you how to make a fully working Jacobs Ladder.
You may have seen Jacob ladders in those old Frankenstein movies where you see electricity travelling up two wires disappearing then re appearing at the base of the ladder.

WARNING: This project uses HIGH VOLTAGES which can kill you. I wont say don't try this at home as it is a fun project but be EXTREMELY careful.

Also This is my first INSTRUCTABLE.

Please feel free to leave comments.

Step 1: Your Components

1x Transformer. (Should be at least 9kv. My one is a 12KV one which i got free from a neon sign shop. If you say your making a Jacobs ladder they will usually give it to you for free or for a low price.)

1x 2m extension cord

Insulation Tape

Copper wire

Ordinary Steel Wire

A base for mounting everything


Wire Strippers and a scissor


<p>What about RFI that could impair electronics? Is that possible with 8-9 kv 20 ma???</p><p>Please contact me through e-mail. This is a essential question. Is it a serious risk when doing the jacob ladder?</p>
<p>can i take only the transformer from a 12v car battery charger and wire the 12volt side to a household plug. and expect to get about 1.1kv. than do it again by attaching the 12votl side of a seconded 12v car battery charger to the output of the first and expect to get near 11kv? or will there be a lot of fire and magic smoke? and if that works i have lots of old home electronics with transformers, will they work? and can i add a 3 third stage? Will a Fly back transformer from an old glass tube TV work?</p>
<p>no this won't work, you really need a neon transformer, the antique ones are best for this </p>
Does the diameter of the rods matter to the output of the transformer and can I place a plexiglass tube around the rods for safety? Oh also does it matter what metal the rods are made of?
Not Necessarily. But bear in mind that if you use rods that are too thin, then it may have the possibility of melting. Yes you can put a plexiglass tube around it, and it shouldn't affect its performance. Nope it does not matter what metal you use. I had used steel in my one
Also be aware that the electric arc will produce OZONE. A toxic gas in high quantities. If you put it in an upside down aquarium or in any sealed environment you can see the effects of the arc on the air in the sealed area. After a couple of hours the air in the aquarium will be brown.
why do you need a transformer?
Because mains of 240v (110v in the US) is not high enough to produce a spark. A transformer is essentially used to increase the voltage (to create the spark) while limiting the current.
will your transormer work if it says &quot;secondary ground fault protections&quot;<br>
my transformer was made in 1999 so it should have the secondary GFI. all I know is that when i touched the high voltage lead to any other object besides the other bushing or the ground wire it tripped the circuit
I just got an old transformer from a heater unit that broke in my house.. It's a 17.5 Kv transformer, but im not sure of the mA number, I can't wait to make one of these! haha or maybe I will try to make the plasma speaker also on instructables
you say that they will give it for free if we say it's for a jaccob ladder but I said it and the womand looked me strangely and asked me why I would like this then she said me it cost 140 euro...
For a used one?
12,000v@0.03A = 360 watts<br><br>this thing will take quite alot of power,<br>are you sure it outputs 30ma?<br>and doesnt just take in 30 ma?
Transformers are about 96% efficient, so there's not a lot of difference between input and output.
I'm surprised that they gave you the transformer for free. Where did you go?<br/><br/>PS: Nice Instructable. <em>+1 and favorited</em><br/>
A place called Neon Supplies in New Zealand
Yay! I just found a small store that was willing to give me one for free! only 9kv but still! I'm glad I didn't buy one on ebay.
Oil furnace repair shops may give you free OBITS. I have a pallet full of OBITS that were on their way to a dumpster.
what's an OBITS?
oil burner ignition transformer's
Like mine?<br> <br> <div class="media_embed"> <iframe frameborder="0" height="246" src="http://player.vimeo.com/video/31410367?title=0&byline=0&portrait=0" width="437"></iframe></div>
Could I use a OBT? It's rated at 15KV 40mA. Great 'ible. AlexHalford
Yep that would be perfect to use
Does drawing an arc from an OBT (such as a jacob's ladder) constitute a short? Thanks AlexHalford
well not really. It could be but it will pose no harm to your houses electrical grid.
It's not the house I'm worried about. I read somewhere that OBT's can be shorted but only for about a minute, then they need two minutes to cool. Can I draw a constant arc from it or do I have to stop after a minute? Thanks AlexHalford
I haven't heard about a OBIT transformer being only used for one minute. Generally you wont run a Jacobs ladder for more than a minute. But if you want to test it out take the temperature of the OBIT before you turn it on. and then take the temperature in 10-15 second intervals. If the temperature rises dramatically you shouldn't use it for more than 1 minute
I'm using a 14kv 35ma Carlin OBIT, rated for continuous duty. As the steel rods increase in temperature, the arc's don't travel as far up the rods. Thicker rods fixed this issue. The transformer has not increased in temperature significantly, but I've only run it for 5-10 minutes at a time.
Oh and yess you can draw a consistent arc from it. Be careful the wires get HOT
OK, thanks for your help. AlexHalford
Whats an OBT?
Its actually OBIT which means Oil Burner Ignition Transformer
OK, thanks very much.
&quot;guaranteed to impress family member'<br /> Haha i would probably get kicked out of the house.... But cool instructable I will try it anyway!
What would you say is the max/min current you'd want for this project?
Roughly between 20-60milliamps. Anything more than that would be overkill.
I wouldn't say over-kill, the larger the mA rating, the wider the arc can grow to be. If you have two, try to put the primaries in parallel and the secondaries in parallel on two transformers that have the same voltage rating. This will add their mA rating and keep the voltage rating the same. But, they MUST be the same voltage rating, even if not identical. I have a setup, right now, with one modified Franceformer (I modified it by removing the GFI unit) 9KV/60mA NST in parallel with one 9KV/30mA NST, essentially giving me 1.5X the power I had before. My arcs don't start at a much closer distance, however, the arcs do pull to a much longer distance. The 10KV/cm is the rule for starting the arc, but after that it's the current of the transformer that keeps the arc going. If you do try what I recommended, I also recommend a variac to ramp up the power to 0.5 input power, if possible. If this isn't possible, I suggest just plugging it in normally. If you end up with a transformer that won't arc from one side to the other very well, you probably don't have the transformers in phase. Switch around the primary connections on one of the NSTs, and you're all fixed. If you'd like to know more, PM me.
Ive made different jacobs ladders using different transformers ranging from 7.5 KV to 50 KV. They all work basicly the same just a fatter arc as the voltage goes up. Ive always wanted to put together a jacobs ladder that would arc 5 to 10 foot accross. Any Ideas?? Ken
Well, to have a five foot arc you will need at least 1,500,000 volts. Because air breaks down at 10000volts to every centimeter. Five feet have 150 cm so you will need a MASSIVE POWERSOURCE. I have made a tesla coil with registers at 500,000volts. The only way you can reach that type of voltage is if you link IN SERIES lots of the SAME neon transformers or those 50KV transformers you have. You will need alot of them though.
You can't link NSTs in series, since they have the center-tap on the secondaries. It makes things horribly inconvenient for guys like us, but they make it cheaper to make the NSTs for companies like Franceformer. If you need to link transformers in series to get a high-power supply, I would recommend MOTs ran off of a 220 source with a high-potential step-down transformer to bring the voltage down to 110/120V (If your microwave was made for 120, that is). This will allow you to have a higher output power (in KVA or KW) on one circuit. Parallel the MOT primaries, series the MOT secondaries and pray to God that you don't kill yourself on the exposed cores. Then, hook it up after the stepdown transformer and there you will have it. A 1A however-many-KV-you-decide-it-should-have power supply. I recommend going for 100 MOTs in series. That would definitely be a world record and would give you 200KV...Although I do suspect that you might have insulation issues at that point. Why not just get an X-Ray transformer rated for 100KV and put in an external series resonant capacitor? It will pull more current, so you'll also need a PFC cap (Power Factor Correction) to prevent this and maintain the lifespan of your transformer. As the previous comments have made note to, you're probably better off building a Tesla coil out of your NSTs that are under 20KV and, preferably, over 10KV. If you have any with 60mA ratings, that would be better, as you double your power consumption right there.
that has it's limits though. you can't pump 10kv into a neon sign transformer primary and expect it to survive for long. You're probably better off building a tesla coil
Technodude92 is true. It would be better to build a tesla coil .In fact i have built a tesla coil. They are incredibly fun to make. I will soon put up an instructable to make a tesla coil as there are none currently. You can find a link to my vid on youtube by <a rel="nofollow" href="http://www.youtube.com/watch?v=crEyOwBe8TI.">http://www.youtube.com/watch?v=crEyOwBe8TI.</a> Mind you i made this video before i fully tuned it. Now the streamers are about 10 inches and the longest spark it made was 12.5 inches. By gettting a bigger secondary more capacitors and more NST power you can increase the spark<br/>
Right now I'm currently using a Peter Dahl Plate Transformer, 21,000 volts at 2.6 amps and its arcing about 18 inches. I built a tesla coil years ago when in school but it only arced about 12 inches and the arc wasnt very impressive. I just recently went to a swapmeet and picked up another plate transformer that put out 50,000 volts at 10 amps. The main reason I grabbed it was that the laminates can be disassembled and either the primary core or the secondary core can be removed. The secondary was wound with about 6 gauge wire, the wire is a flat stock type thats 1/8" X 3/8" and I figure that theres about 125' of wire wound on the core and I have about 1000' of 14 gauge wire on hand that I could rewind the secondary with. I could also play with the primary windings and adjust it to boost the secondary voltage. Theres plenty of room to work with. I figure that when I rewind the secondary I'll only be using about half of the usable space.
anyone have any idea if you can make this portable, i'm a propsman by trade and a battery version would be very useful...
are you crazy do you know how much power that takes.
I hope he does. Do you realize that your microwave oven, when on, consumes about 1KW? It has a transformer in it that is about 2.2KV at 500 to 1000mA (1A). This transformer is only 12KV at 30mA. 12000*0.03 = 360W. Much less than a microwave oven, so I really have no problem with running this in my house continuously, as long as I was able to have a firm foundation and a method of making sure the arc doesn't heat the rails too much.<br/><br/>I seriously doubt that the author is crazy.<br/>
you can buy a $40 jacobs ladder kit from jaycar in australia, im guessing this would be like radio shack in usa, it uses a vn commodore ignition coil and a 12 volt battery
Hmmm, looks like a trip to Jaycar.... YAY ! Was looking at another place, but Jaycar are local. Hope they have it in stock. Many thanks for the heads-up. My 11 year old son and I will have fun making this one.

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