# Jacob's Ladder



## Zombie-F (Apr 12, 2004)

I scored big today! My cousin Steve recently had is oil furnace replaced and I got a free 10000 VAC transformer out of it! I'm finally going to make me a Jacob's Ladder, which will go well with my plan of making a Mad Scientist's lab for next year. I even scored a free plexiglass tube from work to house the wires in for safety. All I have to do is build a wooden box for it and it's done.

I am SO doing a how-to for this thing over the winter. 

Anyone here build one of these yet?


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## gmacted (Jan 18, 2006)

Sweet score Zombie-F!

Here's a link to a how-to if you're interested.


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## Dr Morbius (Sep 21, 2004)

I saw that movie...A vietnam vet sees strange things....oh wait. You mean the device! I'd like to see it built, it's one of those things people talk about, but you rarley see actually done.


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## Sickie Ickie (Jun 20, 2006)

I've thought about it, but it scares the HELL out of me. If anyone does touch inside while the elctricity flows, shall we say bug zapper times 1000?


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## Brad Green (Jul 29, 2004)

Here's a video of one I built a few years back out of a 1200v Franceformer. I used 24" brass welding rods for the uprights and attached a Gabriel starter at the base of the rods just to keep it igniting on a regular basis. It's worked without failure for about 4 years now.
http://img532.imageshack.us/my.php?image=1000013ka1.flv


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## kirkwood (Sep 7, 2007)

those are too cool. give me about a decade and i might feel ready to build something like that.


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## .id. (Jul 3, 2006)

I built one two years ago using a 12kV Neon sign transformer and some straightened out copper tube for the uprights. I just wish I could find a 4" diameter plexyglass tube for it to make it a bit safer...  Here's a pic of mine on the left side....
http://www.i-su-root.com/Halloween/2005/Front%20Room.html


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## Zombie-F (Apr 12, 2004)

I attached two pieces of bus wire to the posts yesterday just to get an idea on the spacing to get the arc to climb. What an awesome effect. The plexiglass tube makes the sound and "snap" of the arc sound so much cooler.

I think I'm going to mount it inside a nice wooden box, maybe put an AC ammeter on the front along with some random blinking lights. This should be a hit in the "Mad Science Shed" next year.


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## pyro (Oct 7, 2006)

I Like That Effect-it Looks Cool On The Back Of An Electric Chair


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## Richie (Jan 4, 2007)

Hey Zombie,

A few years ago I picked up some great ceramic resistors to go along with a Jacob's ladder I wanted to build for my Frankenstein. I haven't gotten to build the Jacob's yet, but I thought you might like to see the resistors I got my hands on. I put my hand in the photo for scale, but they're 3-1/2" high. The wire from the transformer gets screwed to the post inside them and the solid wire simply connects to the screw posts at the top. I was going to connect fake wiring to Frankenstein's neck electrodes with simultaneously flashing white or blue LED's flashing on his electrodes while the Jacob's ladder was running. Anyone who saw it would think the Jacob's ladder was actually connected to him. Having his electrodes blinking was an effect they did in the movie, Frankenstein Meets the Wolfman, and where I got the idea from.


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## Zombie-F (Apr 12, 2004)

Nice resistors! I may have to pick a pair up for mine too. They just have "the look" of mad science to them. 



Richie said:


> Hey Zombie,
> 
> A few years ago I picked up some great ceramic resistors to go along with a Jacob's ladder I wanted to build for my Frankenstein. I haven't gotten to build the Jacob's yet, but I thought you might like to see the resistors I got my hands on. I put my hand in the photo for scale, but they're 3-1/2" high. The wire from the transformer gets screwed to the post inside them and the solid wire simply connects to the screw posts at the top. I was going to connect fake wiring to Frankenstein's neck electrodes with simultaneously flashing white or blue LED's flashing on his electrodes while the Jacob's ladder was running. Anyone who saw it would think the Jacob's ladder was actually connected to him. Having his electrodes blinking was an effect they did in the movie, Frankenstein Meets the Wolfman, and where I got the idea from.


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## Richie (Jan 4, 2007)

Zombie-F said:


> They just have "the look" of mad science to them.


Exactly!


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## Revenant (Mar 17, 2007)

What's the rating on a color TV transformer? I had a TV crap out on me and I haven't thrown it out yet... think it's strong enough for a ladder? I know TV's pack a killing load of juice so it's gotta be pretty high...


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## Zombie-F (Apr 12, 2004)

Richie said:


> Exactly!


Just curious, where did you get those resistors? I'm interested in them now and I'm having a difficult time locating something like it online.


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## Richie (Jan 4, 2007)

Zombie, sent you a PM. Also, doing a search on Ebay for Tesla coils will yield much better results when it comes to parts and transformers than searching for Jacobs Ladders.


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## randyaz (May 26, 2006)

Rev, the TV transforer is called a fly back transformer and requires a driver circuit. If you tear into your tv find the capacitor and discharge it before you do anything else...the cap is what will zap you...

Here's some info to study before you attempt it

http://www.kronjaeger.com/hv/hv/src/fly/index.html
http://www.powerlabs.org/flybackdriver.htm

BE CAREFULL !!!!!


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## Revenant (Mar 17, 2007)

Yeeesh.

After looking at that stuff, I've decided screw the TV idea. If I want a jacob's ladder I'll get a regular transformer.

Tell ya what tho... I did see a home haunt like 2 years ago where the guy made a pseudo jacob's ladder with elwire. He had the rabbit ears going up (they were like narrow PVC painted silver) and around 8 or so curved pieces of elwire arcing between them on a sequencer circuit so they lit up in sequence travelling up. Granted, you can tell close up it's a fake, but from a distance with a black background, and with the right sound loop playing, it looked good. It's worth thinking about, especially if you have kid actors that you don't want getting curious and frying themselves. And it'll run all night on a 9V battery.

I still wanna build a real one though. Tesla coil too.


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## edwood saucer (Aug 21, 2006)

You guys are crazy - I'd zap myself into eternity trying to build one of those...


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## NecroBones (Feb 10, 2006)

I built one in college, sort of... Still tempted to try again.










Main lesson learned-- The rods attract each other. I used something like 12 or 14 gauge wire rods, and they bent quite a bit while it was on.

Also, the transformer I used supplied sufficient volts, but not enough amperage, so it would just keep zapping at the bottom. If I adjusted the rods to be slightly more parallel, it would zap and pop at random locations all up and down the thing. Interesting effect, but not correct.


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## Sickie Ickie (Jun 20, 2006)

Revenant said:


> Yeeesh.
> Tell ya what tho... I did see a home haunt like 2 years ago where the guy made a pseudo jacob's ladder with elwire. .


Now that's a project I could do!


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## Brad Green (Jul 29, 2004)

NecroBones said:


> I built one in college, sort of... Still tempted to try again.
> 
> 
> 
> ...


That's where a Gabriel electrode would come into play. It is a third electrode placed at the bottom of the "V" that is tapped off of any of the 2 primary electrodes. You would make the connection by running two 1 Megohm resistors in series from the primary electrode to the Gabriel electrode. It keeps the spark igniting at the base and the ionization of the air forces the spark to travel up the primary rods. I ran a 6k transformer this way for awhile, then sold it to build a bigger unit.


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## NecroBones (Feb 10, 2006)

Brad Green said:


> That's where a Gabriel electrode would come into play. It is a third electrode placed at the bottom of the "V" that is tapped off of any of the 2 primary electrodes. You would make the connection by running two 1 Megohm resistors in series from the primary electrode to the Gabriel electrode. It keeps the spark igniting at the base and the ionization of the air forces the spark to travel up the primary rods. I ran a 6k transformer this way for awhile, then sold it to build a bigger unit.


Yeah, if I build another one, that'll be useful. I didn't have trouble getting this one to start at the bottom, it just wouldn't travel since there wasn't enough sustained current.


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## Zombie-F (Apr 12, 2004)

My transformer supplies a pretty low amount of current. It's just barely enough to make a working ladder. I have to space the rods "just so" to start the spark and can't increase the spacing too dramatically or I lose the spark mid-way up.

On a side note, I did manage to get the rods to be 36" long today. That's the length of my Lexan tube, so I don't dare go any longer. In fact, I may shorten it up a little since the last three inches of the tube on one end is scuffed all the way around and I plan on cutting it off.

So, now I have to make something to help keep the rods spaced properly all the way up the tube. I have access to a 3D printer at work, so I may have one of the engineers fabricate me some plastic spacers to hold them. Not too sure if the plastic will hold up though. Any other ideas?

Here's some video:


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## Dr Morbius (Sep 21, 2004)

Hey that's terrific! It travels very nicely.


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## slimy (Jul 12, 2006)

Looks great, Z.


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## Otaku (Dec 3, 2004)

Nice job, Z-F! Regarding plastic spacers - do the rods get fairly hot during operation? If so, a good high-temp plastic for making the spacer (and you probably need just one at the top of the rods) would be PEEK. The full name is polyetheretherketone. It has a melt temp of ~700 °F, very high dielectric strength and is easily machinable.


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## Zombie-F (Apr 12, 2004)

I'll likely put one at the bottom and top. The spacing of the gap at the base is critical on mine, and I want to make sure that stays constant down there.

The rods get warm to the touch, but not hot so I don't think I need to be too concerned about heat.

I'll see if we have any of that polyetheretherketone or a similar material around the lab. Thanks for the recommendation.


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## Frighteners Entertainment (Jan 24, 2006)

Nice movement and sounds good too.


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## Zombie-F (Apr 12, 2004)

Brad Green said:


> That's where a Gabriel electrode would come into play. It is a third electrode placed at the bottom of the "V" that is tapped off of any of the 2 primary electrodes. You would make the connection by running two 1 Megohm resistors in series from the primary electrode to the Gabriel electrode. It keeps the spark igniting at the base and the ionization of the air forces the spark to travel up the primary rods. I ran a 6k transformer this way for awhile, then sold it to build a bigger unit.


I think I'm going to try adding a Gabriel Electrode to mine. Getting the spark to start is just so sensitive. If the gap is off by even just a tiny amount, no spark, and if its too close it just stays put.

Plus, I think adding another "thing" to this project will help make it look cooler.


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## Zombie-F (Apr 12, 2004)

Well, I have the spacing of the electrodes to a point where I don't need a Gabriel Electrode, so I've decided to forgo it.

I have got an AC milliampmeter that I picked up for this project as well as a voltmeter on the way too. The ammeter is only rated to 25 mA, which is a little less than what the Ladder Draws, so to counteract that, I'm using a 21 foot winding of 30 AWG wire in parallel to the ammeter (which comes to about 2 ohms). I know I could use a shunt resistor, but I don't really want to be generating any heat, and being I'd need about a 10 watt resistor, that could be quite a bit of heat.

Once the voltmeter arrives, I'll be able to finally start in on the wooden box!


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