Introduction: How to Make a Jacobs Ladder

Picture of How to Make a Jacobs Ladder

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

Picture of 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

Step 2: Assembling the Components

Picture of Assembling the Components

1. Cut the end of the extension cord where you would plug the device into. Strip the three wires and attach them into their appropriate ports. Brown- Live, Blue- Neutral, Yellow/Green- Earth.

2. Then get some lengths of copper wire and insulate it with the insulation tape then attach it to the 2 High Voltage lines.

3. Gets two equal lenths of the steel wire. Bend it at the bottom so the bit of wire bent should be 90 degrees to the vertical bit. Using insulation tape stick the two bits of wire to the base.

4. Attach the 2 high voltage lines to each of the steel wires.

5. The trickiest bit would be adjusting the angle length so the electricity goes all the way to the top.

6. If your electricity rises up the wires and stays at the top then flare out the tips of the wire

7. Once you check all the connections then plug it in. Turn it on.

Guaranteed to impress family members


AldenJ6 (author)2016-12-03

This is probably a terrible question: Would this work if it had 400kV coming from a DC step up convertor?

maxhumphries (author)2008-10-07

anyone have any idea if you can make this portable, i'm a propsman by trade and a battery version would be very useful...

maccag115 (author)maxhumphries2009-03-07

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

maxhumphries (author)maccag1152009-03-08

Thank you Maccag, you've just allowed me to start up a very interesting project. thanks for all the other comments too, very helpful...

RonaldD25 (author)maxhumphries2016-10-03

You probably have your project under control, just as mine is beginning. If you are looking for a project, you might consider helping me with mine. We have a 50 megawatt solar farm about an hour to the south and I want to apply my new invention to enhance it to 58.5 megawatts. They have a 3-year contract to sell their power at $0.15 to $0.17/KWh in Los Angeles and I think that is an unearned profit that should help to defray my needs.

cybergod (author)maccag1152009-06-12

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.

title1pro (author)maxhumphries2009-02-12

are you crazy do you know how much power that takes.

chriskarr (author)title1pro2009-06-25

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.

I seriously doubt that the author is crazy.

fatboyslim (author)maxhumphries2008-10-13

It is possible to make a battery version if you have a small high voltage unit. Try modifying a stun gun and see if that works. I think there are a couple in instructables on how to build portable high voltage power sources

oldmanbeefjerky (author)2011-05-31

12,000v@0.03A = 360 watts

this thing will take quite alot of power,
are you sure it outputs 30ma?
and doesnt just take in 30 ma?

My new Franceformer uses 120 volts and 3.15 Amps or 378 watts on the primary winding to produce 12,000 volts and 30 milliamps or 360 watts on the secondary winding.

sspence (author)oldmanbeefjerky2012-01-15

Transformers are about 96% efficient, so there's not a lot of difference between input and output.

1stcontact (author)2011-07-31

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?

fatboyslim (author)1stcontact2011-08-01

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

RonaldD25 (author)fatboyslim2016-10-03

I find that 1/2" copper pipes deliver a stronger arc, and I have never gotten wires as straight as pipes. I have not tried 3/8" pipes.

HappyHelper (author)fatboyslim2013-10-31

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.

RonaldD25 (author)1stcontact2016-10-03

I am using 1/2" copper pipe 18" long, it was producing about 100 strong arcs then it began to occasionally "hang up" at specific imperfections on the pipes, so I put the pipes in a lath to polish them. Now the arc seems to have lost direction and is out of control. I am using the arc's radiation to treat solar panels to increase wattage output by >17%, it is important to not burn the panels. I think the ozone gas is too turbulent or my arc's emission point is too broad, I will try a more narrow 18" long slit aperture.

RonaldD25 (author)2016-10-03

I need to build a 4' high commercial-grade Jacob's Ladder and ma having difficulties keeping my 18" ladder operational for an hour.

RonaldD25 (author)2016-10-03

I have used 3 electrodes to produce 2 alternating arcs for about 5 minutes, I don't know why they quit, the 12,000 volt, 30 milliamp FRANCE transformer did not heat up on 3-foot welding rod electrodes. I have to treat solar panels 8' wide, so I need many arcs running side by side.

SHOE0007 (author)2016-08-22

What about RFI that could impair electronics? Is that possible with 8-9 kv 20 ma???

Please contact me through e-mail. This is a essential question. Is it a serious risk when doing the jacob ladder?

pgenious (author)2015-01-17

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?

tim.yoak (author)pgenious2015-03-10

no this won't work, you really need a neon transformer, the antique ones are best for this

bishopfamily (author)2013-06-18

why do you need a transformer?

fatboyslim (author)bishopfamily2013-06-18

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.

kdbacho (author)2012-01-21

will your transormer work if it says "secondary ground fault protections"

clevelandstorms (author)kdbacho2012-07-25

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

A.C.E. (author)clevelandstorms2012-10-17

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

o0JohnnyReb0o (author)2009-08-31

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...

sspence (author)o0JohnnyReb0o2012-01-15

For a used one?

Einsteins Circuitry (author)2008-01-12

I'm surprised that they gave you the transformer for free. Where did you go?

PS: Nice Instructable. +1 and favorited

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.

Everfalling (author)sspence2012-01-15

what's an OBITS?

sspence (author)Everfalling2012-01-15

oil burner ignition transformer's

Alex1M6 (author)2011-12-31
Like mine?

alexhalford (author)2008-07-02

Could I use a OBT? It's rated at 15KV 40mA. Great 'ible. AlexHalford

fatboyslim (author)alexhalford2008-07-03

Yep that would be perfect to use

alexhalford (author)fatboyslim2008-07-05

Does drawing an arc from an OBT (such as a jacob's ladder) constitute a short? Thanks AlexHalford

fatboyslim (author)alexhalford2008-07-05

well not really. It could be but it will pose no harm to your houses electrical grid.

alexhalford (author)fatboyslim2008-07-06

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

fatboyslim (author)alexhalford2008-07-06

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

sspence (author)fatboyslim2011-11-29

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.

fatboyslim (author)fatboyslim2008-07-06

Oh and yess you can draw a consistent arc from it. Be careful the wires get HOT

alexhalford (author)fatboyslim2008-07-06

OK, thanks for your help. AlexHalford

technodude92 (author)alexhalford2008-10-10

Whats an OBT?

fatboyslim (author)technodude922008-10-11

Its actually OBIT which means Oil Burner Ignition Transformer

alexhalford (author)fatboyslim2008-07-03

OK, thanks very much.

history323 (author)2010-02-03

"guaranteed to impress family member'
Haha i would probably get kicked out of the house.... But cool instructable I will try it anyway!

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