Picture of JACOB'S FORKS?
Check It out in my Art Exhibition: http://truscott-posthuman.blogspot.com/

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

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.
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
BrysonReece4 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: http://www.instructables.com/id/MAKE-A-HIGH-VOLTAGE-SUPPLY-IN-5-MINUTES/ I haven't tried it but it looks like it will work. It also shows how to determine the correct pins to power.
emcelhannon5 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?
coolfordy5 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?
Mudbud6 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?
mattccc6 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 Dave6 years ago
What do you do if you don't hear a spark sound.
noahdsmith6 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.
Derin6 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!
santy226 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
locofocos7 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
awkrin7 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.
Was this response posted on April 1 and lost in the aether for 2 days? It dinna sound kosher to me, having ate many a 'cuted wienie,suffering no ill effect and tasting no acidity. In addition, my vague recollections of chemistry (and a quick Googling) indicate that electrolysis of salt water yields chlorine gas, hydrogen gas and sodium hydroxide solution. The only gas I ever detected was wienie steam. Hydrogen and chlorine require ultraviolet light to react. Maybe if the wienie was sliced and placed in the sun before any of the possible minute quantities of gas dissipates, you might get some HCl, but it would be neutralized by the NaOH, yielding good ol' brine again. It might be interesting to test the pH of the wienies before and after their electrocution... I suppose "pickle glow" is actually deadly ionizing radiation?
electrolysis is really only a concern with dc.
Yeah, none of those chemicals are even remotely toxic, not even a drain-cleaner's main active ingredient. Perhaps the general wording of your post proves my point, as you seem almost drunken and disoriented. FYI, chlorine is one of the most toxic elements known, as it kills everything in even minute concentrations, and an ultimate antibiotic disinfectant for all surfaces. Sodium hydroxide (lye, or "caustic soda") dissolves flesh on contact (everyone needs a caustic oven-cleaner in their diet for proper nutrition), and hydrogen is not exactly part of the nutrition pyramid either. Where do you get this religious-right science that says hydrogen and/or chlorine need anything to react with anything else to become toxic? UV has as much to do with their toxicitiy as a penlight lit on the surface of Saturn has to do with the gastro-intestinal tract of a rodent in New Guinea after a lunar eclipse when Jupiter is in retrograde. Jumping Jesus H. Particular Christ, have you read the research in the past 60 years? All of the above is not FDA-approved for a healthy diet (or even a surviveable one), and even though it's the FDA, I still agree. I mean, really......seriously? You admit to the toxins and see no problem? Have you voted republican in the last 7 years? Are you a direct descendant of Harry J. Anslinger or a relative of George Walter Bush? I strongly recommend a CAT scan, and perhaps a skilled neurologist to determine the severity of your last concussion. I mean really, if you're going to contest my point, don't do it while proving it for me. It kinda hurts your case, if you didn't know. That was your argument to prove me wrong, right? I sure hope not. I expected better from you from your previous comments.
Perhaps when you sign up for remedial Chemistry, you might consider remedial English, as well as Anger Management. My point, while not stated outright, is the quite obvious one, that cooking wienies by direct electrical resistance does not yield any of these chemicals, just a warm, slightly singed wienie. Even if it did produce HCl (which it doesn't) it would be nowhere near the concentration of the hydrochloric in your very own tum-tum. ("battery acid" is sulphuric, not hydrochloric, as you misinformed poor tech-king, below)
Ummmm "admit to the toxins?" I stated the reaction products of saltwater electrolysis. I then stated that none are detectable in an electrowienie. No taste or odour of chlorine, not even as much as one can smell or taste in ordinary tap water. No slippery feel of sodium hydroxide, not even as much as might remain in a bowl of grits, after they're rinsed and cooked. As for hydrogen, horror of horrors, you're breathing some right now!!! Too high a concentration might deprive you of oxygen (lighting one up probably wouldn't be the best plan either), but this would be quite a few orders of magnitude more than one might get from a li'l ol' wienie.
Regarding the ultraviolet, I never said diddly about it having anything to do with toxicity of either gas, rather that uv or heat or some other initiator, is required to get a mixture of hydrogen and chlorine to react to produce your fabled hydrochloric acid, that you referred to in your original post. I was also trying to make a point about how the actual products of this (hypothetical) electrolysis might be worse than the surmised HCl. (Apparently subtlety is no longer in high demand)
Drunken huh? I might possibly have been a little high (I'm sure Harry J. Anslinger would not have approved) but much more coherent than your response.
The bit about pH testing was a highly veiled reference to that mystical branch of sorcery known as "science", practitioners of which do things to "test" their theories before browbeating others with their sage wisdom.
Please excuse any inferred hostility or sarcasm. None was intended, but it has been a somewhat trying week for me. I can only conclude that your posts were written under similar circumstances.
By the way, just who the Hell is George Walter Bush and why must you malign him so? I'm sure George Walker Bush and his fellow GOP'ers might appreciate my vote, but they ain't gonna get it due to my not being American, and my having about as much regard for their party as I do for the Conservative Party of Canada, which is none whatsoever.
Thanks for reading. Please be mindful of that pale orange bar, under the reply window, lest you hurt my little feelings.

Ta ta
Hydrogen is a minor atmospheric constituent. The globally averaged atmospheric mixing ratio of H2 fluctuates at present around 500ppb. Yes, 500 parts-per-billion. We ingest many more dangerous elements at far greater quantities. Okay, so your point on how I am already breathing it in? Yes, wet-cell batteries are sulfuric in nature. You may believe it or not, but that was intended as a preface to even responding to the post. Well done. "The only gas I ever detected was wienie steam. Hydrogen and chlorine require ultraviolet light to react. " The heat you claim not to exist is in the electrolysis of the weenie in question. History betrays you... Your candor is admirable, and your content amusing in a shield of relevance. No hostility taken BTW. As far as my remedial english, you don't have a leg to stand on really, as I speak fluently and do not speak your dominant language of French. Enough from me on this, I fold to relevance to this project, not from your reply. I have no need for the last word.
electrolisis turns water into hydrogen and oxygene. how do you get hydrocloric acide?
Fresh water alone. Add some salt and you produce battery acid, and you know weenies have salt. The hydrogen will bond immediately to the chloride. Any water in your weenie will have salt in it. Perhaps I should have clarified this first.
You won't get battery acid from salt in water electrolysis.. You can get hydrochloric acid that way since Cl2 is passed at the anode, and H2 at cathode.. Battery acid (lead-acid car battery) is about 35% sulfuric acid.. You can make that by burning sulfur and salpetre over water, but it would need to be boiled stronger.. Making any strong acid at home is way more work than its worth, and EXTREMELY dangerous on large scale.. Hardware stores carry most, and this biodiesel fad is making purer products easier to get..
Energize a lead peroxide plate and a lead sulfide plate and you get sulfuric acid, hence the name "lead-acid". I have capably produced many gallons of sulfuric acid for my high-school lab eons ago. Manufacturing sulfuric acid at home is extraordinarily easy, as well as hydrochloric acid, and hardly more work than it's worth, unless you are impatient. No, you won't get "battery acid" from just salt-water in electrolysis, but you will get hydrochloric-acid quite easily. I demonstrated this as a teacher's aide in physical sciences by not only creating acid, but demonstrating it burning through the metal container it was produced in. It is only dangerous when you don't know how to handle it, and what to store it in. Hydrochloric acid and sulfuric acid can be stored in glass or plastic containers, can you name which one goes in which without searching the internet? I warn that I am schooled in old-school film developing that employed both acids, I think I know what I am talking about. The sulfuric acid content in say, a car battery depends on it's charge. This is how hydrometers can measure the state of charge and the health of such a battery. Sulfuric acid can also be produced when electrolysis comes from an AC source and you throw in a match. You also seem to have missed the hidden trivia in my original post. You fail for not reading fully before responding. You are also not aware of the hydrochloric content in electrolytic batteries. I think I already agreed to drop this, so I am doing so now. GOOD DAY to you, sir.....I am forever blocking any further responses on this topic via script, so do not expect that I will see this topic again. The script is active as soon as I close this window, which is the moment after this post is ACK'd by the server, INIT QRY starting now.
yes. it would have helped a lot.
if you did you wouldn't want to eat it it would taste like metal and the high voltage would ionize it making it taste even worse
Yeah, it does taste kinda gross and metallic. Might be an improvement for some really cheapo wienies, though. It also takes longer than I like to wait for a wienie, and never does get particularly hot.
hinge7 years ago
Prometheus,you should study more chemistry and definitely "at source",which means books-unfortunately mostly thick ones.Regarding cooking a"weenie",most of comments are pointless,since AC current has zero effect when it comes to electrolytic action.If anode/cathode changed polarity 50/60 times per sec,what kind of electrolytic action would that be?And making"gallons" of sulfuric acid is beyond any home schooled chemist(unless one purchase the stuff and "produce" it out of a bottle).Education usually pays off tremendously in a long run,regardless a subject.Greetings Hinge
puffyfluff7 years ago
Neat idea!
no, if you complete the circuit with your finger and your foot, then it could be fatal. electricity doesn't just spread out in the body, it takes the path of least resistance. that's from one side of the finger, around the bone, to the other. if that path happens to be through your heart, then it's lethal. don't ground your feet, ground your wrist.
DrCoolSanta7 years ago
I have heard of tonns of people dying because they opened up their monitor to fix it. Lol, thats funny.
BFeely7 years ago
Don't use the ground on the circuit board to discharge the CRT or you could fry the electronics. All the monitors I have ever taken apart have a warning label inside telling you to discharge to the CRT's "aquadag." Since there are braided metal straps on the monitor, contacting the 'dag, just wrap the ground wire around that when discharging.
Levetate7 years ago
Wow!! what are you trying to do,you should of stuck with the two copper rods,you shouldnt carry the force back to the monitor,lucky you have the contacts insulated on both sides,there is roughly between 30 and 40kvs travelling through those contacts,this picture does not show a jacobs ladder,and you should of insualted the jacobs ladder too, for safety.
The project is about "Jacob's Forks," not a jacob's ladder! Anyway, nice project!
Derin7 years ago
I saw your monitor was still plugged in the whole time!D-A-N-G-E-R-O-U-S!!!!!
triggernum57 years ago
Didn't the monitor you were using have a 'no sugnal' mode that kills the electron beam? Or perhaps your just drawing limited juice used to show a small "No Signal" floating message.. TV circuits are typically easier to get rocking out of the box, but monitors seem to have heftier flybacks and better transistors..
Botfly7 years ago
Is this mostly to make a visually appealing spark or are there other applications for this? If it's mostly for aesthetics what are some more efficient and safe ways to do this? (Just curious but does this take a lot of current?) Does anyone know how those lightning-in-a-ball toys sold in novelty shops work?
Those "lighting-in-a-ball" toys aren't dangerous at all. They use a high frequency alternating high voltage, but it has BARELY any amps. My multi meter couldn't even measure it. The reason that there are big "lightning arcs" is because the glass globe is filled with a gas. Usually Argon. If you took one apart, and took the electrode out of the glass, you would see that it only makes little tiny sparks less than a millimeter long. However, the little tiny spark can burn you, but you don't really feel anything. The reason the arcs are so big in the glass bulb, is because the gas is very conductive. Look at this article on Wiki to learn more.
those lightning balls are usually several kv, but almost no amps. i think 20 kv is the highest, because at 35 or so you get x-rays. this is purely for looks. and this takes current. thats what keeps the arc going. this is the only application for mots for that reason.
You should have no fear of X-radiation even at well over 12 trillion volts of discharge, or you'd be required to put on a lead suit in every electrical storm. X-rays come from a CRT only when it is extremely overdriven, because so many electrons saturate the confined space, they strike each other and are passed through the CRT screen with awesome force (relative to electrons, anyway). The X-ray protection circuit in any CRT-device will shut the unit down if it detects X-rays, or a probable cause for them, such as the flyback shorting a few windings. All CRT's emit a minuscule level of X-rays, but in such low levels that it'd take over 10 years of 24/7 exposure to equal one X-ray exam.
yes, you should have fear. you should read up on tesla. because he was the one who discovered that: when you pass above approx 45kvdc into a partial vacume, you produces x-rays. although this is not a risk on most screens, nor with plasma globs, it is if you place a lightbulbe on top of a tesla coil.
I have not seen any CRT below 30" that goes above a 35kVDC anode voltage. Also, compare the displacement of a light bulb vs the 15" CRT being used. Again, you should have no fear as this level of saturation in a CRT is very hard to achieve, and again, the X-ray protection circuit will shut the entire unit off if it even suspects there is the possibility of excess X-radiation occurring. You will also note that the discharge between the forks is not in any such vacuum. I happen to Know Nikola quite well thanks.
i have heard of crt flybacks being re-wound and giving over 45KVDC. the exact voltage varies. im not sure about an actual crt, but above around 35-45 kvdc, lightbulbe plasma globes DO give off X-rays. and although the crts detector will cut power, if you remouve the flyback and drive it with a transistor setup, the x-ray shut down will obviously not work i merely suggest you read up on tesla because it wa him who discovered that you can produce x-rays this way
I agree that a flyback outside of it's native circuit has no such X-ray protection, and yes, a flyback normally designed for a 30kVDC output can be made to put out over thrice that, but again, we're talking about saturation of a gas in the volume of a lightbulb as opposed to a CRT. You are right, at that level of saturation, X-rays will be emitted, I never argued against that. In open space however, such emission is not possible due to the mass of the surrounding "envelope". There are too many bound electrons in the surrounding air to be released at a rate to produce X-rays. Remember, X-rays are produced when a gas's atoms have electrons froced from them at such a rate that the constant exchange results in an EM disturbance, such as the emission of X-rays and other radiation. The first level of emissive radiation is low-level RF interference that interferes with tv and radio tuners, and also has an AF component to it. Electrical discharge spans a wide spectrum, from audio frequencies to HF, VF, VHF, and UHF easily, but it dies-off before it hits the K-band (microwave), far below the bandwidth of X-rays. Your concerns are well-founded, but not of consequence in this particular situation. Your candor is perfect if someone tries to replicate the Tesla experiment, I expect you to be the first to speak up on such a dangerous experiment, should someone do it. For everyone, yes it is true that a common household lightbulb exposed to 40kV can emit X-rays, so don';t take this debate out of context. Never put a common lightbulb on any tesla / van-de-graff generator. I might add that I've already read that documentation over 15 years ago, so yes, I am familiar. Thank you for sharing though.
In open space however, such emission is not possible due to the mass of the surrounding "envelope". There are too many bound electrons in the surrounding air to be released at a rate to produce X-rays.

yeah. im not talking about regular arcs. im talking about arc in partial vacumes (like those plasma globes or light bulbes). in open air, its fine x-ray wise. uv and ozone are another story.
Oh, well I never disagreed with that. I thought you were stating that an open-air arc produces X-rays. Perhaps a mutual misunderstanding then. We agree to agree, just not at the same time.
seems like a mis-understanding.
hock3ydud37 years ago
i would suggest that NO ONE does this, because CRT monitors can hold up to 10,000 volts of electricity, EVEN AFTER being unplugged for days, weeks, months etc. Dismantaling one could cause you to be shocked, which would result in burns or even death.
Correction: CRT's can hold up to 30kV of pure static DC with enough current to "teleport" you from one side of the room to another. See my warning about killing this charge. Do not attempt this project if you have not learned to respect electricity.
pure static? if you mean the capacitors, thats not static, its sstandard power. and so are the electrons in the tube. and while on the subject of capacitors, a lot of caps charged to high voltage pulses can regain a charge via dielectric memory. its not instant, but eventually, even if not plugged in, the caps can regain a full charge.
Alright, lemme clarify some... In an electrolytic capacitor, of course it's not a static buildup. It retains power with the exact same principle that a common car battery does, just with far less ability. True, there is a memory and a desire to retain a charge, but they can in no way come to full charge without an outside source, any better than a battery can become fully charged by letting it sit. The internal resistance is too high and the electrolytic is not "that well motivated". Electrons in a vacuum tube of that size are another matter. Considering such high voltages are present, the charge can be retained in the absence of an actual conductor. While the net capacitance is quite low as measured on a Z-meter, it's capability to hold a charge is extraordinary. If you don't believe me, try it on an older TV without anti-static coating on the screen. even after turning the tv off, there is still a strong static field on the screen. If you were to charge a crt, and then just dangle a metal object *with no path to an actual ground), you would see a spark jump. Straight DC needs some path to reach ground, where as static electricity just needs a less-charged object. DC flows, static equalizes, flowing only one way..
i wasnt talking about electrlitic capacitors; i was talkign about the high voltage ones that use poly-somthing-or-other as a dielectric. those ones can regain nearly a full charge via their dielectric memory if pulsed for long enough.
You mean dry-type capacitors? I have trouble following your theory on this since there is no reactive substance surrounding the plates. If you have something to prove otherwise, I'd love to see it for my own cerebral database.

See capacitor types for more info.

The only capacitors I know of that can even develop a "recovery charge" are of the "wet-type", and even then, a full charge is not possible, especially in-circuit. If you are reading this by a standard DVMM, your readings will be flawed due to capacitance, of all things. Only a Z-meter can read capacitance accurately. Dry-type caps can hold no charge as their dielectric/plate combination relies on a purely static exchange and not a chemical one. As far as I know, only a wet-type cap can develop any form of recovery charge, under any circumstance, and that reaction is not reactive enough to recreate a full-charge state. Just as well, the only caps in any CRT capable of holding any charge significantly are the power-supply filter caps, which mean nothing in terms of the horizontal section (source of any HV in any CRT over the 134V main power-supply voltage). The potential of those caps is blocked by the fact that their non-reactive potential is stonewalled due to an insufficient and rapidly-deteriorating charge to pass that current through the circuit by engaging the switching mechanism of the circuit that follows them.

FYI the anode button on a CRT does not get within 1/9th inch of the gas in the tube. It is simply embedded in the glass to a prescribed depth to induce a capacitive voltage potential, exciting and (electrically) polarizing the gas so that the beam current is anti-polar relative to it's "environment", and can be diverted by the deflection yoke properly to the oppositely-charged phosphors on the display surface of the CRT to create the display. On my CRT monitor, I see this as a result of a focused but negatively-charged beam of electrons colliding with the positively-charged phosphors coated on the inside of my screen to produce the visible light that i see as a result of the reaction. This is why the CRT's "suction cup" is always the anode (positive electrode; the opposite is the cathode, for a CRT, this is the grid voltage relative to the anode, and the grid is the anode relative to the heater filament that keep the color guns exited). The "minor anode" or "focus voltage" goes to the grid and determines the beam-scatter out of the gun(s). The dag-ground is the ultimate cathode and is usually closely-related to the heater-filament, and the polar-opposite of the HV anode, or flyback output.

All vacuum tubes have some form of a cathode, grid, and anode (a negative, neutral or control, and a positive. in simpler tubes such as a (6AG4? I forgot my RCA-Victor models)). In any case, all three exist, and CRT's are the only prevalent use of vacuum-tubes today, and will soon be lost to new technology forever. Take note of the full name, "Cathode-Ray Tube".... CRT's run on the same basics since the birth of the vacuum tube, with exception to the focused-beam current and physical design of the tube itself.

It won't be too long before your old TV-set becomes a Smithsonian-worthy piece of vintage technology. History-buffs, gather any schematics you can now, before they are lost. Per my part, I have a 50-year-old book on vacuum tubes that rarely sees the light of day....

My "portable" tube-based television will be worth a fortune if I can find a genuine era-age tube to replace the bad vertical output amplifier triode (IIRC), and then I'll just display it as a historical conversation-piece than to condemn it to go stale in a museum just yet..but that's another story altogether.

(sorry, I'm a card-carrying member of the vacuum-tube fan club)
im talking about dry caps (poly-somthing. i think propelyn (definitly spelt wrong)). and im also talking mainly about removed from the circuit. the phenomenon is called dielctric memory. ill see if i can find the link to the page. from what i remeber, the dielectric lines up (or was it the electrons in it? not sure here)anyhow, it can gradually regain a charge. it was on a tesla coil web site. the event only occurs to caps pulsed with high voltage. although i agree its unlikly in a crt, its possible, and definitly a risk with tesla coils.
Poly-styrene? See the link "capacitor types" I provided in my previous posting. I am aware of what you mean, but even for a 35kV dry cap left alone for weeks, I have never had any indication of a recovered voltage. Electrolytics do that as a result of the electrolyte itself and the reaction to the dissimilar plates, just as putting a copper rod in one side of a lemon and a zinc rod in the other automatically produces a charge.
no, not styrene, my bad. its the high voltage pulse rated polypropylene ones. im not sure if the phenomenon is unique to tesla coil or not. i found out about it on a web site for them though.
At the beginning of the Instructable, `jacobfork` tells us how to discharge the tube and circuitry by putting a grounded wire underneath the suction cup to dissipate the voltage stored in the tube.
Jeddychan7 years ago
hey could you use one of these old moniters as an arc welder? that'd be a cool project to try... if its possible...
Kiteman7 years ago
Oh... I have an old CRT getting in the way in my shed.

What I could really do with, though, is an 'ible about stripping the flyback out of a CRT whilst retaining it's ability to generate high voltage. And possibly re-boxing it so that it doesn't kill me.
nope. to properly drive a flyback without the crt pcb, you need to re-wind the primary. on most flybacks today, thats impossible. now, if you had an old black and white tv....
If you happen to have just enough space for 3-5 turns of 18AWG magnet wire, and are running a 2N3055 oscillator, you can pull it off. However, the vintage TV's are a better source for customizeable flybacks, and are more durable than the newer, modular type. Just make sure that, above all, the ferrite core is not cracked or the transformer is useless.
But can I get rid of the tube etc?
ALWAYS GROUND THE CRT ANODE (under the "suction cup") TO THE DAG GROUND OR THE BACK OF THE TUBE FUNNEL BEFORE EVER ATTEMPTING TO REMOVE THE ANODE CAP, NO MATTER HOW LONG IT HAS BEEN SITTING! Just pull the board out and try it. In most cases, it will work. Just be aware that the kine socket (the board that plugs into the back of the tube) is live to at least 7kV grid voltage. You can just unplug the deflection yoke (large electromagnet at the base of the tube neck) without trouble. Any wire going to the dag ground (metal straps near the face of the tube itself) is a viable ground, and usually chassis ground. One other connector to the tube is the degauss-coil that wraps the perimeter of the tube face, you can not only disconnect this freely, but can be used for a stock of magnet-wire for another project (it's just a huge loop of about 24AWG magnet-wire with class-A insulation). To salvage the wire, unwrap the tape, do not cut into it. Have a reel ready, as once unbound it will do it's best to tangle. You should be able to run the board without the CRT in the circuit, but don't expect that you can simply put it all back together again and the monitor will work fine. Keep in mind that any CRT (picture tube) is under an extreme vacuum, and just a bump on the gun section can result in a relatively-explosive decompression. If this concerns you, put on some goggles (hold your breath and keep your mouth closed!) and pinch the tube nipple at the end with needle-nose pliers to shatter it, and the tube will "gas" safely. It's a vacuum, you keep your mouth closed to make sure that you don't get glass in your mouth. If you are going to dispose of any CRT that is not protected by the case, I strongly recommend you gas the tube for your safety and the safety of others.
Great, thanks for the information.
dunno. at any rate, the flyback is useless
Astinsan7 years ago
This is to much for the cheese ball transformer in that old monitor. Probably won't last to long before it fails. Neon sign transformers make a better driver. Has anyone tried a florescent ballast? Anyone doing this should think about sending 70,000+ volts to the ground in your wall. You could kill anything that is grounded to it. UPS's, Satellite Dishs and cable lines are usually grounded to it too. I would ground it to the actual ground with a spike. Keep your wits. Take every safety precaution you can. Then have fun.
The ground on your home outlet eventually leads to a grounding rod and/or your cold-water pipe. In this case with a device that generates it's own high-voltage, the best ground is the antithesis of the source, or chassis-ground. Leading such a charge to earth-ground can be dangerous because it will change your mean ground potential relative to the line "hot". And a UPS will certainly be protected from ground-surges, as they are expected to run during lightning-strikes and cope with various surges from all angles. Most surge suppressors lead transient charges to ground anyway. Fluorescent ballasts only generate about 4000VAC at most with a pathetic current...not worth the effort, believe me I tried them decades ago...
How about a vehicle spark coil? Anyone try that? I thought about doing it with a motorcycle coil. I had a yamaha yzf ignition at one time and I know it throws a spark without a trigger. Would DC output make a more stable ladder? I would hope a ground would not go on a water pipe. Most pipes these days are made of plastic. Damn pex... To many thief's stealing the copper these days. I am pretty sure it isn't permitted anymore. But then again I have seen some real bad wiring jobs. All it takes is one person breaking 220/230 to 110/115 by grounding the neutral... Now the shower will really wake you up.
A 220 circuit is just two opposing hots. The neutral on this circuit is the same connection as the neutral on your 115 outlet. Your home receives 220v from the pole, and that is run straight to your 220v appliances, and split to run the 115v branch. You don't however, ground the neutral as the potential between it and ground can be significant to cause a leakage current. The requirement for a grounding point is a stake that goes down at least 6 feet, and many pipes feeding the house are already deeper than that, and certainly not made of PVC or copper. If your water heater is easy to get to, try looking for a clamp on the input pipe. A wire attached will be the ground for the water heater. It is not only allowed, but required procedure in every case I can think of offhand.
Trace II7 years ago
Holy crap! I just bought the exact same monitor yesterday for a dollar! Best dollar I ever spent...
i actually just took one of these apart today. but it was also trash day so the trash man got the tube(screen part) but the flyback and the board are completely intact could i still use the same setup and get it working?
See my post above
emilk7 years ago
If my recollection is correct do not mess with CRT's they contain poisoned gas! that will probably harm your well being and shorten your life. Correct me if wrong.
Xellers emilk7 years ago
No, CRT monitors don't contain poisonous gas. There are parts that are under vacuum. The reason you may have heard that opening CRTs is dangerous is because the tubes can implode.
They do not contain a poisonous gas, they contain a poisonous film of phosphor on the inner surface of the screen, which is what translates the electron beam into visible light that we see.
Leon Close7 years ago
Would this emit any harmful radiation?
well.. there certainly is ozone and that is not exactly good for you. just make sure you are in a ventilated place. cheers WL
You'll know if you are breathing in too much ozone, as it has a smell I can only relate to unflavored gelatin, or almost soapy. Well-advised to use in a well-ventilated area.
ramses Xellers7 years ago
well, if you used heavy metals, there is the POSSIBILITY of accidentally making an xray tube which would, um, emit x rays. as i recall, the flyback driver in the monitor pulses at either ~1mhz,which may emit ~1mhz electromagnetic radiation, in the AM radio bands The arc, especially if white and hot like in the pictures, emits UV, which is bad for your eyes... so wear polycarb glasses to block UV pretty nifty otherwise. and i am pretty sure the case could be grounded. ramses
X-radiation comes from an over-driven CRT when the tube is beyond a saturation point. For the most part, you will suffer no more X-radiation than you normally do on a daily basis.
I am pretty sure this thing will make plenty of UV, so careful with your remaining eye :-)
Are you sure? I remember an experiment like this in high-school physics class with an arc produced by high voltage AC, I think Tesla was involved (well not personally). I remember calcuating the range of wavelengths of EMR emitted, some being a bit nasty. That was a while ago though, I've probably forgotten some important details.
kd1uc7 years ago
Try using a spark coil from an old oil burner or a neon sign. Plenty of juice and plugs directly into 120 VAC, A car spark coil with an old tube radio vibrator (or other make and break circuit) will make an awesome display that is also portable (sort of). Like you said it can be lethal so keep one hand behind your back when testing. PS Love the basic idea, Way Cool!!! Never would have thought of forks.
Actually the best way to keep a shock from killing you is to grab your other wrist, negating a path through your heart. Also, test a potentially "hot" connection with the back of your fingers as if to backhand the terminal. If it is "live", the resultant muscle contraction will actually pull you away from the source. It'll sting more, but worth it to save your life. Also, the "capacitor" you refer to is not the conventional type. That capacitor is the picture tube itself. The most ideal gound is the "tube dag ground", which can be connected by the grounding straps near the face of the tube. You can also use it's mounting frame (mounts the tube to the face of the chassis). Any bare wire braid near the tube is a ground. Since oven gloves will not protect you from that kind of voltage, use a thin-shank screwdriver and alligator-clip a jumper from the shank to chassis-ground and simply slide that under the anode cup. Be sure to hold that connection there for at least a second, and never rub on the outside of the tube's funnel, or you'll generate a new charge. To remove the anode cup, pinch it hard at the top parallel to the anode wire and work it to one side, and then the other, while pushing down slightly. The hook is shaped like two opposing "L" s or an equivalent design, and above is the designed method for removal. Be sure to set your electrodes as far apart as you can make them, and use this for very short durations, as the flyback will quickly overheat and burn out under that level of current. ALWAYS ground the tube anode to dag ground (metallic coating on the back of the tube funnel) before touching any part of the monitor for adjustments. You may also want to add more heatsink to the horizontal-output driver, usually the largest transistor with the largest heatsink.
camiller kd1uc7 years ago
For what it is worth, I used a 10,000v electric fence transformer for mine at the Jr. High Science fair. In 1980...... dang I'm gitten old.
dorit827 years ago
The EHT from the flyback transformer is around 25.000V DC. I think Jacobs ladder needs AC to work. A neon sign transformer is the usual tool for this kind of project.
dc works fine for a ladder.
Levetate7 years ago
i dont think you know what you are doing..........
Jawatech7 years ago
LoL i thought your carpet was ground beef
If it was, you could cook it with this thing! That would mean taking "make sure you ground it" TO THE EXTREME! MWAHAHAHAHA!!!
Nyanman7 years ago
like cooking those hot dogs with some forks...
gmjhowe7 years ago
Looks cool - great use of an old monitor!
mrmath7 years ago
First, I always thought Jacobs Ladder was that wooden toy where the blocks flip back and forth. Second, I thought the red "carpet" was a pile of red playdough squished through a hair maker. :) Nice instructable, btw.
That is another type of Jacobs ladder. BTW Nice instructable!
LinuxH4x0r7 years ago
austin7 years ago
thats is really cool im actually going top make something like this.
That's freaking awesome. I'm going to try this hopefully. And I mean it. +1 rating. (added to favorites)
budsiskos7 years ago