Low Cost Jacob's Ladder Made From A Salvaged Oil Transformer

No Mad Scientist or Halloweener's display is complete without a Jacob's Ladder aka the Traveling Electric Arc. These are easy to build, look really cool, and can be very dangerous if you're not careful. Anything like that is my kind of device!

This unit was made at basically zero cost. The transformer was salvaged from an old oil furnace, the power cord was cut off a discarded appliance, and the wires laying around the shop. Have fun and be safe.

Step 1 Safety First - Extreme Electric Shock Hazard!

If you're not 100% comfortable working with electricity, either find someone who is, or get more education before attempting this build. The transformer used here puts out 10,000 volts at 23 milliamps. Most stun guns only put out about 3 milliamps. I don't know exactly what this would do to a person, and I never want to find out.

ALWAYS disconnect the power before working on it, or adjusting anything.
DO NOT touch the terminals or rods when the transformer is energized.
DO NOT put anything conductive (including you) close to the terminals or rods when the transformer is energized.
DO NOT do anything stupid.

Transformers of this type do not vibrate, make noise, light up, or let you know they are energized in any way. Just because there is no arc does not mean the unit is safe. Always check to make sure it's unplugged before handling.

Comments

[somebody12345]

it would not kill you. it takes 50 ma to kill a person

[tinyrunninger]

i have been wanting to build one of them for years thanks for your input

[waldosan]

insanely good article, i just found out a few days ago that i have quite a few of these sitting next to the furnace in my house. i think i'll wait till spring comes to really play with them. quick question, would it destroy them if i connected them in series I.E. connecting one transformer's HV leads to the primary of another transformer?

[bloomautomatic]

I don't know if it would destroy it, but the outcome would probably be bad. With a 10,000 volt output and 120volt input, that's a ration of 83:1. If you put 10,000 volts on the primary, it would be trying to put out 830,000 volts. At the same time, the amperage going in is very low, so the outgoing amperage would be reduced by a factor of 83. That's the theoretical part. In the real world, I suspect it either wouldn't have enough amperage to actually make the voltage on the secondary, or if it did, the insulation would start to fail.

I don't know for sure since I've never done it, but I wouldn't try it.

[LaxLuvr]

Sweet! im 12 and im wondering where i can get an oil burner transformer and if anyone would even giv me one. And YES I know the dangers of playing with high voltage and i have taken apart many CRT's and other high voltage devices (if disposable cameras count) : p Please reply.

[dog digger]

Be very careful. the oil in that transformer is a big, big cancer risk!

[bloomautomatic]

The oil furnace ignition transformers typically aren't oil filled. The one's I've seen were all solid. Usually only larger transformers, such as ones used for power transmission, are oil filled. The cancer danger you mention is from PCB (polychlorinated biphenyls) found in those older transformers. The US banned production of PCB in 1979, so MOST transformers won't have this, but when in doubt, take all precautions.

Vince

[LaxLuvr]

Im also going to build a wooden enclosure around the transformer and a plexiglass enclosure over the electrodes. and would a 15 amp 120v switch work for the input leads?

[rocketman221]

yes that switch would work for the input. make sure you keep the hv lines away from the wood its quite conductive at 10-15kv.

[tristantech]

Wouldn't the wood burn if you touched it with high voltage wires?

[DIY Dave]

could I use a microwave transformer?

[dog digger]

No.
they output only 2.5kv and too many amps.
you need at least about 9kv (give or take)

[IzzyP]

I did this for physics class and got some mad extra credit! The difference between a B+ and an A- thanks for this instructable!

[bloomautomatic]

You're very welcome and I'm glad to hear it helped you out. Stuff like this shouldn't be extra credit, it should be part of the regular curriculum. You're on your way to becoming a real mad scientist!

[IzzyP]

Ha ha thanks, I wish this were in science classes to begin with too! Science can be a lot more interesting when you do the right projects.

[conrad2468]

I made a dry ice bomb in science class and got extra credit.....DEFINITELY not part of curriculum but it is cool....

[bloomautomatic]

Keep up the good work. Math and science got me to where I am today. Just be careful with anything that explodes. In high school, I managed to get extra credit for a chemistry experiment that went very wrong and resulted in a rather large explosion. Just thinking of it reminds me of the smell.

[rohang]

Where are you right now? Cause that's a really cool Jacob's Ladder. Should I feel sorry for Jacob, though...? How did that name come about? Great instructable.

[Nicademus]

I touched one of these just as it was being powered up..... Oops. Luckily I was seated and also fell away from the device. All in all, on the scale of suckiness, I'd rate that experience a 9 out of 10.

[kontajussparkz]

ya dude you aint lyin i have three transformers my self and the most powerful outputs 15kilavolts
at 20 miliamps and i can tell you first hand it hurts like hell! my glove insulation had a whole and i took the brunt of the shock down my right arm and out my right leg and ive been told be numerous electricians im lucky to be alive =P so BE CAREFUL and always work with your left hand behind your back(in the event of a shock this helps keep an arc from forming over your heart possibly sending it in to venticular fibrilation)

[Dextro32]

Hi Kontajussparz seriously spealing though it only takes 6 Miliamps to stop your heart , make sure your your "Grounded" ie wear Rubber soled shoes, wear heavy Rubber Gluves, rem 6 M.A. your rt will stop Beating Bro I like experiminting as well as the next guy but be Carefull... Dextro32

[tristantech]

I believe it takes at least 50 mA AND over 100 volts AC or several hundred volts of DC to kill you. And it would take even less current at 12 kV.

The point is, these transformers can seriously hurt or burn you and I would not be surprised if one killed you.

And, I do not think 12 year olds should be messing with these unless you are under supervision of an adult or electrician.

[handysmerf]

Old wives tail about working with one hand behind your back. An electric shock can kill going through your body in any direction. SO TURN IT OFF FIRST.

[rohang]

Tip: don't touch.

[coolchris1225]

made it, worked out great. great instructable i love showing people my jacobs ladder. You can get the transformer for free... found mine in an old farm house.

[Pie Ninja]

Once I start working I'm gonna make sure to make one of these.

[wheelharp]

This is just a little question I've had for a while but does anyone know what state of matter fire is?I thought it would be plasma but I'm only 80% sure.Just wondering.Thanks.

[Pie Ninja]

Fire is not matter, it's just heat.

[12V]

the reason the wires move is because they get hot. if the arc stayed in one place the wire will glow or even melt!

[mdj817]

Just finished my baby... 12kV at 30mA... Behold, the Annihilator! (mwahahahahaha etc.) Click for high quality goodness...

[reano_r_4a]

can you teach me how to make one??? please.... thanks

[difflock]

Do you think it would be possible to use an electric fence energiser to do this? Most put out over 6,000 volts...up to 10,000 volts

[boosmeeee]

i just made one of these and it is sweet

[sbukosky]

I happen to be a heating technician and instructor. I've had accidental shocks from these transformers several times in my career. Most are from a single terminal which is around 5,000 volts. You'd have to somehow get across both terminals to receive 10,000 volts. I've also had several coworkers receive shocks from the in the course of work. In only one case did I have to see that a technician went to the hospital as he complained of chest pains. In my case all that happens is that the hand getting the shock will involuntarily jolt away. Once a screwdriver flew from my hand and into a plaster wall behind me from it. Otherwise I can best describe the sensation as being hit by a baseball bat. It hurts but I've not had any lingering effects other than renewed respect for the things!

[carpespasm]

I've always wanted to make a jacob's ladder with a nice beefy transformer like this. Does it have to be a non-GFI style one or can a GFI transformer be modified to work without it? Does anyone know of an inexpensive source for these transformers?

[rocketman221]

i got a 12kv 60ma nst from ebay for $20 including shipping.

[crrake26]

That is a nice component for an evil scientist to boast. You could try different sizes of the poles, so the sparks go in different directions???

[Fire Onyx]

Easy place to pck up one of these would be at a neon sign shop. I live in a smaller town, and we had 4 in the area. I said I was working on a jacob's ladder for my sister's science project, and got it for free.

[Koil_1]

Great Instructable. Keep up the good work!

[Koil_1]

They vibrate because the plasma you see between them is really more of a solid than most of us may think. You're right to think it has something to do with magnetism too because it does. Plasma is very magnetic and likes to be short literally collapsing in on it's self thus pulling the rods inward. In the past I've found it best to use stainless steel or tungsten rods for this. They still vibrate but not as much because of their rigidity. It's easy enough to get a good bend in them if you have a propane torch to heat the area to a bright orange.