Picture of JACOB'S FORKS?
Check It out in my Art Exhibition:

Well, originally I wanted to make a Jacob's ladder which if you haven't already heard can be extremely dangerous! They are high voltage and if you complete the circuit with your finger it can be fatal...So, be very careful or just don't do it.

Most of the instructions I found used a transformer from a neon sign to generate high voltage and make the thing arc. I didn't want to go out and buy a transformer but I did have an old CRT (Cathode Ray Tube) monitor collecting dust. So, I decided to put it to good use and make a variation of a Jacob's Ladder.


Monitor (CRT)
Wire (12 Gauge?)
Plastic Tube
Materials for Insulation
Remove these adsRemove these ads by Signing Up

Step 1: SPLICE

Picture of SPLICE
Open any monitor up, and one of the first things you will see is a big suction cup attached to the CRT. Attached to it is a wire that is at a few thousand volts higher than ground because there is a capacitor somewhere that is still charged up.

The first thing you should do is put on some oven gloves, and get a piece of insulated wire. Attach one end of the wire to a ground pin (look around on the circuit boards etc.) and poke the other end of the wire under the suction cup until you hear a spark noise. Do it a few times until you are SUPER sure everything is discharged, and even then use a multimeter to check the voltages of everything your hands come near.

A flyback transformer in the monitor generates a few kV that is used to accelerate electrons in the CRT to hit the screen. There should be at least two large leads coming out of the transformer. One goes towards the suction cup near the front of the screen (thats the super high voltage one), another goes to the rear end of the tube (should be more or less 0v).

Cut the high voltage wire that goes to the suction cup, splice in a wire of your own and solder.
1-40 of 124Next »
CirceWelder3 years ago
Does the monitor still function? Could it be put back together and used as a pc monitor still with the forks lit? That would be a sick pc mod
hruodger4 years ago
How do you handle the X Ray emission? As I remember, an open monitor, tv, etc, would emit a little amount of x rays. Even if the cover is made of plastic it shields the radiations. Now that it's open, there could be some of these. MOst of th CRT's have a sticker with a warning.
yell no the tube gets some power but not enoff becuse hes shorting it b 4 t gets to it
BrysonReece3 years ago
Will this still work if I disconnect the monitor 'tube'? I built this and I LOVE it, but I've been wanting to downsize it to just the PCB, no monitor.
yes pull out the pcb clip all the grounds you can cut all of the wire excpt fore ground and hv out be carfel ask if u need any help
dog digger4 years ago
Not back and fourth. That will only happen if the TV is ancient. If it's newer than 1985-1990 it will be DC. One way
I think he means it sparks between two random close tongs, but keeps switching between them. For example, numbered counter clockwise, like a chip, there might be a spark between tongs 1 and 8 for an instant then maybe 3 and 6 next and so on in a random pattern.
So, I've got a sack of high voltage transformers salvaged from CRTs, but the low voltage side has a ton of pins (10-15). Do these transformers normally use 12vdc? 120vac? Will Bad Stuff (TM) happen if I run them at the wrong voltage? These were all free so I think I will just experiment.
This instructable showed a way to power a flyback transformer: I haven't tried it but it looks like it will work. It also shows how to determine the correct pins to power.
emcelhannon4 years ago
I've done this a couple o times. I get at least a 1 inch spark for about 2 seconds. Then a relay cuts the monitor off. I've considered bypassing the relay, but I don't want to overload the circuit and lose the driver. And I've tried putting 10w resistors, (2k) on our main line from the flyback. That weajend the arc, but it still cut off. What do guys think is the best solution to this problem?
coolfordy4 years ago
do older screens have higher voltage flybacks?

Technet935 years ago
Use heat shrink and hot glue.
Turnip1235 years ago
Do you mean AND until you have depleted the capacitor?
Mudbud5 years ago
I really want to make thiis but all I have is the computer monitor curcuit. will it still work if the wires that whent to the monitor are gone?
mattccc5 years ago
i did this with a portable crt tv
interesting read! Thank you for taking the time to post this... and yes, we enjoyed the red carpet ;)
DIY Dave5 years ago
What do you do if you don't hear a spark sound.
noahdsmith5 years ago
awesome, i thought you might like to know that we tried it to and it looked great.... until the monitor died :-) thanks anyway!
Nice instructable :). I very much like your art as well, good luck.
Derin5 years ago
The way you do it,you can play *insert author's fav. game here* while having a light show at the same time!
santy225 years ago
put a wiener between them and see wht happns
the BBQ of the futuer!!
EnigmaMax6 years ago
bravo, a great design. probably not a beginner's project though...
And furthermore by the looks of your forks that monitors flyback has a capacitor in it (does it make a buzzing sound while running) so it stores up a charge then pulses. If your flyback didn't have a capacitor you would have a constant arc which would build up heat and rise. as far as I know all monitor flybacks have a capacitor in them therefore monitor flyback jacobs ladder is invalid and forks are boring
The capacitor in the circuit is the monitor itself, detach the high voltage leads from all of the parts of the monitor (including the suction cup), and it should work fine.
Correct me if I'm wrong but if your using any ground that isent directly on the flyback/before any components after the flyback aren't you risking frying the drive circuitry of the monitor
locofocos6 years ago
I tried making this, and it works! Or it did. Let me tell the whole story. I went out and got an old CRT monitor for free that was destined for the garbage. I took it apart and it had the suction cup thingy on the back. I tried to discharge it, and there was no zap. So I assumed it was discharged (it was). I then began to cut the wire going to the suction cup thingy and attached a 12 gauge wire to the end going to the transformer. There was another wire coming out of the transformer, but I decided to go with grounding at another spot (probably where I went wrong). I looked on the pcb for something like GND or GRD but couldn't find anything. Near where the power came in, the ground plug (biggest plug, on the bottom) split into two wires. One of the two wires went off somewhere, one went to the metal casing. I decided to attach my ground wire to the metal casing right next to where the ground wire attached to it. Then I put the plastic case back on, running the wires through a hole I made near the back. I bent the wires, already stripped, into a shape where they were pointing towards each other. There was a gap of about an inch. I hooked it up with an extension cord, and sure enough it worked. It wasn't very loud at first. The arc wasn't very bright, and it was kinda red, maybe a little orange. I came back to it after lunch and made a ghetto jacobs ladder out of some bailing wire, duct tape, and styrofoam. This didn't work. It seemed like the electricity was going through the styrofoam, so I shut it off and unhooked it. I put the wires back into their original shape to try it again. The arc was the same color and brightness as it was before for a few seconds. Then it suddenly turned blue and bright like I expected it to be at first. It also started making a rather loud buzzing sound, not like any jacob's ladder I've heard before. I tried moving the wires apart some while it was turned off and turning it back on. It worked, but it started sputtering and then eventually shut off. Now when I turn it on, it just makes a short soft humming noise every few seconds. I tried playing with the gap of the wires and tested the power socket, nothing worked. I'm going outside to try it again to see if it works. I'll reply to this with what I find.
yeah, still getting nothing but a noise every second or so. i think the ground wire may have come loose cause i didn't attach it too well. I'll try opening it up again and see what I can do. if i dont reply again, that means nothing worked and i'm probably gonna go back for another monitor pretty soon :P EDIT: It's broken. I even tried hooking it up right, but I already fried something important. But, I will be going out to get another free one on monday (writing this saturday night). One thing that was odd about mine was that it never held a charge after I unplugged it. When I first got it and tried to discharge it, I didn't get anything from it. Then once I started it up (grounded to the body of the monitor instead of the other transformer lead) and unhooked it, it still didn't hold a charge. But I'll post how the next one turns out.
bit of a delayed response It probably went arye because using the mains ground probably fried a few things on the monitors control board it didn't happen to this guy so I guess it wont destroy some monitors but it isent a good idea
Hes right this is just plain dangerous
awkrin6 years ago
this is not something I wanna do! well if I had a workshop, maybe.. this thing is really dangerous. I once tried to put back a computer I just took all the pieces apart, it kinda worked, but I wanted to see if the big cooling block is too hot(from the power supply, which wasn't in it's case) and got shocked, cuz I didn't connected all the ground wires. it was quite pleasant, more like a wave going across my hand, but this thing can kill u
Perhaps you shouldn't be taking things apart you know nothing about. Computer power supplies were NOT made to be taken apart by the end user. I've taken many apart however, and usually the heat sinks themselves say 'RISK OF SHOCK- DO NOT TOUCH'
junits15 awkrin6 years ago
that is bacause the two big capicitors in it were still charged, if you had let the PSU sit for a little while you wouldn't have got shocked.
i had a similar thing happen but a wave not so much more a tsunami of pain and rapid contraction of muscles that i didn't even know i had lucky i just suffered to burns on my fingers and not a heart atttack
topmack6 years ago
Jacobfork, have you ever seen a 'trick' using a paper towel tube, two pieces of aluminum foil, a 9v battery and some type of RC circuit, that will cause an increasing, building shock if the two pieces of aluminum are connected between the hands?
ratfink886 years ago
haha - so entertaining.
tetanus7 years ago
Can you cook weenies with them on the fork?. Love the red carpet.
Probably not enough power to cook the weenies. You can, however, cook weenies with regular household current. Attach the forks to a lamp cord, or some such. It's a good idea to plug into a power bar that you can switch on and off. Two warnings: 1) Don't touch the forks while it's powered up! 2) Don't use "good" forks.
3) don't eat them as any water will be converted to a hydrochloric acid due to electrolysis.
1-40 of 124Next »