With limited knowledge in electronics, I made a Cockroft-Walton generator - Page 1
Forum section: electronics / beginners

author: zeal422
author_rank: Contributor
timestamp: June 01, 2023, 04:33:57 am
content: Hello fellow nerds! Happy to be here!Here is the video of it:https://i.imgur.com/0t2oJrf.mp4I used a small model train variac that outputs a max of 20VAC, that I connected to a transformer in reverse, so the input is the output and vice versa, after that I get 380VAC, I feed that through the circuit and get 1kVDC.Now all I need is a bigger driver... All I have as of now is a sunmaster 5KV HID starter... I have to test it to see if that would work for the input.Here is the simulated circuit I made:https://i.imgur.com/5BGuiZH.mp4In the simulation there is one extra stage. On the breadboard is without the one extra stage.If anyone has some advice for a noob like me... please, bring it! The more I learn the better, as this is one of my hobbiesI would like to know what type of diodes and caps should I be using. I've seen some yt videos with people using these blue round ones, but I'm wondering what value should I buy ? Because now the input being only 380VAC from the reversed transformer I don't need huge caps, but if I were to increase the input to 1-5kV then I'm guessing the caps and diodes should be rated for that voltage, correct ?Thanks and have a great day!

author: cybermaus
author_rank: Frequent Contributor
timestamp: June 01, 2023, 05:42:36 am
content: Welcome here at EEVblog.So what do you mean with "HID driver". I assume the transformer right?I am not sure you need a bigger transformer, if all you want is some better arc's, this one seems reasonable, the weakness of the arc may come from other things. What are the specs on the transformer?Also be careful with bigger transformers. You may think you are working isolated and safe, but even isolated voltage can hurt and even damage you if it has sufficient power behind it, and you accidentally touch both wires. Which is why I suggest you should improve build quality before you improve the energy used.And your multimeter is not rated for anything above 1000V. In any case, please also understand your multimeter is also a source of leakage for the generator. In fact, your arcs may improve if you disconnect the multimeter. To simulate the multimeter in your simulator, you should add a 1M Ohm resistor. Most good multimeters are only 10M Ohm, but this (in)famous cheap one may be less at 1MAs to the construction of your schematic: I think a breadboard may not be the best. All these strips and wires probably has a lot of capacitance in the wrong places. Rebuild it using good sturdy solder connections. Though admittedly that may loose structural integrity quickly. Can you get hold of someprototyping PCB?As to the component values: Those blue capacitors you see areY class protection capacitors.Purely theoratically, both the diode and the capacitor, each individual one, gets a maximum oftwicethe input voltage.So at 380V in, which is 380*root(2) or 535V peak, you would need 1070V rated elements.(it also means you likely only have one stage working in your setup)-----It is all a bit high though. Maybe you should it first more focus on the theoretical part. See if you can get multiple stages working, with lower voltage. Yes, it is not so exciting, but it does build better experience and understanding:Give it only 12V directly from your train variac, and see if you can get 5 stages working, pushing it to, I don't know, 40 or 50 voltsModel your simulator better (not those absurdly high 1uF values) , and see if each stage gives you the correct output in real life. (though remember, measuring it will affect its working, so how to measure is a bit of a challenge)Build it all properly on experiment board rather then breadboard.Once you understand this 12v to 50v, measure each component individually, and see what voltages each components get (should be double) and then build up.Oh, and try and keep it high voltage, but low energy. Meaning low capacity in your capacitors. If you check those Y capacitors, you'll see they are in the pico and nano range, not the 1uF you have in your simulationPS: if you source stuff, try and find a Romanian store rather then ALiExpress.I could argue chinese quality, or supporting local shops, but also consider, every $1 piece you get from china comes with a 1 month wait time, only to then find you need yet another component, wait yet another month. To keep the speed and enthusiasm going, finding a good local supplier, even if 5x more expensive, is vital.

author: zeal422
author_rank: Contributor
timestamp: June 01, 2023, 11:08:41 am
content: Hey there cybermaus and thank you very much for replyingI will be answering the questions you had for me so the project is better understood.1) HID driver here for context:It outputs 4.5kV Here is the video where I put it on a multimeter to 'test' it and by test I mean destroy the cheap multimeter to see the arcs which were quite disappointing because it blew the resistors quite quicklyHere I used a full 1000W ballast with a big cap and a 5kV igniter.2) This is a little tiny transformer that has 220V input and 12V output, and I was feeding it in reverse with 20V so thus the 380VAC output it gives in reverse, but it doesn't have that much power, I have put a 220V motor on it as the load and it spins it but the drop in voltage is quite high, it only shows 140V with the motor fan load. So it's not a good transformer for this project, that I'm aware of3) If you have some advice for me regarding isolation, that would be wonderful. I am planning of buying an actual main's voltage auto transformer (variac) and isolate it myself, I've heard these are not proper isolated. I heard that if you only connect the earth ground to the case and desolder the ground from the windings then it's properly isolated... Now you tell me if that is actually correct.4) Regarding the multimeter, unfortunately, yes I know that I can only measure up to 1kVDC without a HV probe which is why I was researching to make one myself because these can be expensive, will see how that one goes5) Good to know, I didn't know you can lose efficiency through a breadboard... I've seen couple of videos on YT with people doing this project on a breadboard and their sparks worked great, but ofc they had a bigger input and bigger caps / diodes. I was thinking of one of these websites where you can build a circuit, send to them and they will make you a PCB for it as you designed it and all you have to do is just solder the parts in place, I was thinking of doing that after more testing on the breadboard and digitally scoping the circuit.Regarding the values of caps and diodes, I thought that their values only matter for the ones on the input, so let's say if you have 220V input you are ok with 500V diodes and caps along the whole circuits further. Is that not true ? Because that's what I've read, correct me if I'm wrong ofc.I just now tested it again, the train variac outputs 19.5VAC on the terminals I've attached it to and after 2 stages I measure 50VDC. So I'm thinking the stages work.. ? Or do they... I want to mention the caps are not all the same, the diodes are... but the caps not, the diodes are rated for 1000V according to their data sheet, but the caps are random 400V+ from desoldering random PCB's.I see, yes, I will modify the values of the caps for my simulation, thank you for pointing that out! Unfortunately I don't have a multimeter that can measure capacitance, that will be the next thing I will buy, but for now I have to see their code written on them and calculate it.I know what you're saying but some of these parts, specially some caps that I want to buy that are 30kV (the blue ones) are quite expensive here, so I might as well grab a bunch from china and that's that, will work on other projects in the meantimeHow about these ones ? Are these ok ?https://www.aliexpress.com/item/1005004412184948.html?pdp_npi=2%40dis%21RON%21RON4.08%21RON3.84%21%21%21%21%21%402101ef7016856191840848414e0d13%2112000029091157792%21btf&_t=pvid:1a4a85ab-114e-41e2-bfe8-5bf9a5b4e79c&afTraceInfo=1005004412184948__pc__pcBridgePPC__xxxxxx__1685619184&spm=a2g0o.ppclist.product.mainProductAnd I was looking at these diodes:https://www.aliexpress.com/item/1005004964124987.html?spm=a2g0o.ppclist.product.6.47c6SYbnSYbnp7&pdp_npi=2%40dis%21RON%21RON6.54%21RON6.54%21%21%21%21%21%402101ef7016856191840848414e0d13%2112000031176555787%21btf&_t=pvid:1a4a85ab-114e-41e2-bfe8-5bf9a5b4e79c&afTraceInfo=1005004964124987__pc__pcBridgePPC__xxxxxx__1685619184Let me knowTo end the response... would be great if you could give me some diode codes and cap codes to search for that can safely operate a 5kV input, just so I can have a better idea what I should buy.quick EDIT:A question I forgot to ask is that I've heard you can measure high voltage based on their arcs, so for example 1cm per 1kV is that actually correct ?Thank you very much mate for the well detailed response!

author: cybermaus
author_rank: Frequent Contributor
timestamp: June 01, 2023, 12:02:20 pm
content: Quote from: zeal422 on June 01, 2023, 11:08:41 amSo the HID drive has nothing to do with your generator. Just a different item that also generates sparks.QuoteRunning a transformer in reverse can be OK. But running it in reverse with a 66% overvoltage ... I am no expert, but I think likely you'll saturate the core, meaning you put more magnetic flux into it than it can handle, causing it to start to magnetically short and get hot. I am surprised you even god 380V out of itAlso, be careful. As mentioned before, high voltages can hurt and damage you, even if they are "isolated" from mains. All you need to do is accidentally touch both ends.As long as you use these wimpy transformers, it will probably only hurt, but you seem pretty insistent you want to beef up the stuff. It can still damage, and even kill you, even if isolated from mains.QuoteAutotransformers are never isolated. Not sure where you heard that story about disconnect ground, not sure what they meant by it, but autotransformers are never isolated. And most variacs are indeed of the auto-transformer type. (well, most proper variacs. Your little 12V model train set variac probably is an isolation transformer)Important for auto-transformer type variac is that you ensure the mains neutral is connected to the common base of the auto-transformer, so that the variable and low output of the variac is also low in regards to ground. But it will not be isolated.QuoteDid you already model in your multi-meter into your simulator. Assume it is a 1 MOhm or 10MOhm resistor, and see how it affects the working of your generator, even theoretically.You can maybe make it having less influence by using a 100MOhm resistor, but then your multimeter needs to be pretty sensitive to still measure anything.But I hear you. I have been looking at an isolated high voltage isolated probe for my scope for a while, and yes, they are rather expensive.QuoteWell, when you have pico-farad capacitors, the breadboard be a significant impact. For micro-farad, not so much. However, microfarad is quite hefty for this. You probably want to stay in the middle with nano-Farad.But you do not need to go all the way to custom PCB. Just some island board or stripe board and some soldering gets you a ling way.QuoteHmm, somewhat. Again, twice the input voltage for each diode and each cap. So for 220V AC, a Y or X cap rated for 500V is indeed OK,because those ratings are AC. *BUT* most caps areDC rated. So you first need to calculate your 220V AC into its peak DC component, which is 220V times root(2), and then double it.Note: the yellow blocky caps you have are X2 safety rated. Those blue ones are Y safety rated, and those are rated ACBut the red and gray ones you showed, those are normal film caps (not safety) and rated DC.QuoteI feel somewhat uncomfortable guiding you to 5KV experiments when you are obviously a beginner. All for helping someone learn, but can't you start with something simpler like a 555 with a blinking LED?

author: joeqsmith
author_rank: Super Contributor
timestamp: June 01, 2023, 12:43:35 pm
content: Quote from: zeal422 on June 01, 2023, 11:08:41 amMy guess is that your disappointment stems from the supply folding back once the circuit arcs. I've seen similar posts with people using insulation testers. If your goal is more drama, maybe a larger supply? Maybe have a look at PhotonicInduction's channel. He has some big stuff.I have some HV supplies but they are fairly low current and not enough energy to be a big concern. This DC supply is only a kV but requires some respect. Rather than folding back, it will shut down during an over current condition. Tiny compared with Andy's setup but still potentially lethal. Dead is dead.

author: zeal422
author_rank: Contributor
timestamp: June 01, 2023, 02:17:45 pm
content: 1) "So the HID drive has nothing to do with your generator. Just a different item that also generates sparks." Correct, I haven't tested it as an input for the circuit because I don't have the caps and diodes to handle these voltages yet. For now all I have are just 2 MOT diodes, which I think they're rated for only 2kV.2) I know what you're saying hehe, I have a lot of these scrapped transformers lying around and tested them all, some do get hot under even small load like a multimeter, but this one is weirdly not getting warm at all, even if a run a big 220VAC bobbin coil fan with it in reverse like that... I also have to test this with a beefier amplifier transformer that I have and with a MOT that I've removed the secondary and rewired it at around 35V that has about 500amps, that one... scares me a little bit because I've shorted the wires to see what happens on the output, and at 35V and 500amps, it god damn blinded me and I smelled the ozonefor sure a much more bigger flash than this 1kV circuit I made, so for now I won't use that one, I just wired it to have it there. I used it to spot weld some metal because it had more than 1000amps at 1.8V, it made some nice sparks that one, but I got bored and rewired it for testing much higher voltages at big amperages. I have touched this 1kV wires with just one hand but both outputs and increased the voltage until I felt something while measuring with a multimeter... well, around 300 or so RMS you can feel tingling and finger muscles moving with more voltages. And of course if you press on the probes your body resistance goes lower and you feel it more. So you're right even these pewny small transformers can hurt you so ofc I take as much precation as I can, it's funny because of me saying that I touched the wires to test the voltage3) Regarding the information about isolating auto transformers I took from Mr. Carlson's lab:4) The voltmeter in the simulation, well... it can measure anything because it's simulation, you don't have to buy a special virtual probe for thatIt just measures things, it can be hundreds of millions of volts.5) I have changed the caps in the simulation from uF to pF but nothing really changed, the voltages are exactly the same as with 1uF.QuoteI put the gray one at the end rated at 2kV to filter the output better, maybe it doesn't do anything but that's what I thought it did if I put it in parallel with the output. So do I really need to up the caps / diodes doubled the previous one for every stage ? Is that actually how it works ?QuoteHeheThat's boring mateWhen the times comes to learn that, I will, but for now all I want and need are big consistent sparks. No worries, I know as far as the amperage is low, like not using powerful transformers to do this, everything will be fine, so for now I will continue using power sources that don't provide much amperage. I think I will purchase the diodes and caps I've showed above because you didn't say anything like "they won't work" which basically means they're fine for this projecthehe. Also I want to mention again that I know the risk and I assume it. I'm always wearing my trusted rubber slippersand I'm on a wooden surface and never touch 2 wires with 2 hands, I always (if I have to) touch them with one hand so there is no conductivity through my heart... Again... not doing this with risky voltages and current (amps). That's a no no, and I know.So basically Y caps are the way to go for this project and these diodes I've showed above I'm guessing these are good too, It's fine if you don't want to tell me, you can just winkThanks again very much for the response, very much appreciated!

author: zeal422
author_rank: Contributor
timestamp: June 01, 2023, 02:24:19 pm
content: Hey there Joe!I think my problem here are many things... first one is for sure the power supply... having this transformer in reverse does not provide many amps. The caps, the diodes, basically everything is weak. Although it works, it's very weak. I will put a 600k resistor on the output to see what happens If I were to touch both wires, because that around my body resistance. Because that tells me why the arcs are so weak.Cheers for the response and video, that's a neat power supplyI'd like to see the insides.

author: cybermaus
author_rank: Frequent Contributor
timestamp: June 01, 2023, 03:08:39 pm
content: Quote from: zeal422 on June 01, 2023, 02:17:45 pmWell, I would not dare going up again Mr Carson.And it seems I do not need to. I think you may misinterpret what he told you.The first half of this video, the one with the disconnecting ground wires, is about *isolation* transformers, and about how adding ground to the modern variants, in combination with the fact oscilloscopes have grounded probes, can undo that isolation. In that specific case you can redo the isolation by disconnecting the ground. However, this has nothing to do with *auto* transformers.The second half, from 13m56, deals with auto-transformers, and note how he mentions "there absolutely is not isolation"Also, the picture he shows at 14m25 shows what I mean with keeping neutral (and not hot) connected to the common point of the auto-transformer based variac. This is especially true in a country like romania where I believe non-polarized German style plugs are normal.Quote from: zeal422 on June 01, 2023, 02:17:45 pmYes, the voltmeter in the simulation is an ideal device. Your actual voltmeter leaks (between 1M and 100M ohm, depending on the quality, I am assuming 1M for your cheapo one)You can simulate the leaking in your simulator, by adding a resistor, and see what it does. Let me show you with my simulator, that I shown you before.(also note that this is precisely why voltmeter and scopes show the actual value this in their specs, so engineers can take this into account)Only an ideal voltmeter:With a simulated 1M Ohm load:With a simulated 10M Ohm load:Try the same in your own simulator. Also now (with the simulated multimeter leakage) try the difference between 1uF and 1nF. You will see that now there is leakage to deal with, suddenly the value of the caps does matter.

author: zeal422
author_rank: Contributor
timestamp: June 01, 2023, 05:35:11 pm
content: I genuinely forgot the video exactly where I saw the desoldering part. But I also watched this and many more info videos like these:https://youtu.be/_pEmpvcNmXg?t=400to be sure what I'm doing. I think I get the jist of it. I understood the part that no auto transformer is isolated because the earth ground is connected to the winding itself. It should only be connected from the input to the case and that's it, but in their wiring they solder another earth ground coming from the winding towards the switch, which is weird but that's what the chinese do, maybe they have a reason for it but that is no isolation.That's a neat website tester, kewl! Will try and build in that too to compare. And yes I will add the 1m ohm resistor as load after the multimeter as you showed

author: zeal422
author_rank: Contributor
timestamp: June 02, 2023, 05:28:40 am
content: Hey maus,You were right regarding the multimeter, while in circuit it did reduce the sparks a little bit.And I think I will go 14kV for now, with these diodes:https://www.aliexpress.com/item/1005004659879053.html?spm=a2g0o.productlist.main.1.3b335c17xJ5iah&algo_pvid=bcee8c29-5feb-4c61-95af-7183cd0c80b4&algo_exp_id=bcee8c29-5feb-4c61-95af-7183cd0c80b4-0&pdp_npi=3%40dis%21RON%2111.8%2111.8%21%21%21%21%21%40211bf31716856803148567798d07e4%2112000030013624395%21sea%21RO%212276964599&curPageLogUid=8Kg5i8vJrdbdand these capshttps://www.aliexpress.com/item/1005004901333259.html?spm=a2g0o.home.15002.5.49232145qYYFld&gps-id=pcJustForYou&scm=1007.13562.333647.0&scm_id=1007.13562.333647.0&scm-url=1007.13562.333647.0&pvid=c5e812c0-2fb5-451d-98a1-a4c5695e4898&_t=gps-id:pcJustForYou,scm-url:1007.13562.333647.0,pvid:c5e812c0-2fb5-451d-98a1-a4c5695e4898,tpp_buckets:668%232846%238115%232000&pdp_npi=3%40dis%21RON%213.35%213.35%21%21%21%21%21%402103251316856798095542549e7966%2112000030957369606%21rec%21RO%212276964599&curPageLogUid=wZ92vWTqF5GEAlso I have seen this schematic on the internetand was wondering why is an inductor there at the start ? Would that add up more quickly ?

author: RJSV
author_rank: Super Contributor
timestamp: June 02, 2023, 05:32:12 am
content: I am tempted to suggest this thread get CLOSED. Maybe go find a dirt track with some cool cars to race around. But I read that some people were saying mostly, uh, you've proved to barely even comprehend the differences between AC and DC.Now I'm a beginner skill level with high voltages, but certainly it is special category that has lots of non-intuitive aspects, such as single contact shocks that do not need an obvious full circuit.Might be a mistake, to even allow this thread to remain, I mean; just think if a couple dozen folks started with this interest, all the while poo-poo'ing the replies expressing doubt, about your abilities...But then I can appear to be rude, sometimes,...I've heard people say.

author: coppercone2
author_rank: Super Contributor
timestamp: June 02, 2023, 05:40:19 am
content: without going into insulators, I suggest that you clean your work bench so the tools and parts are on another table you have to turn away from that thing, so you are only doing one thing at a time and there is never the malfunction of reaching behind the setup. When you leave the pliers under the wires because you just had to tweak something you get twacked... the rule is only one tool at a time or 1 part at a time and every time you finish you turn around and put it back on the other table even if its tediousremove one screw, turn around and put screw on other table. 1 jumper wire, you do the same thing. so long its clean around it you are WAY safer, then there is no incentive to do anything stupid.and probobly if you persue this the thing you wanna do is go on digikey and buy wire rated for the voltage you are working on, regardless of your construction technique, that is too much to go into.

author: cybermaus
author_rank: Frequent Contributor
timestamp: June 02, 2023, 06:17:01 am
content: So I think I do agree to the previous two posters.Not even being a pro myself, I do want to help people who are even more beginners, but you seem a little too focused on your arcs.And it may be the language, after all English is not the native language to either of us, but your responses seem to lack something, they seem to often just miss what I tried to explain. Maybe it is my skill as a tutor.You seem pick out what you want to hear, and ignore things you do not grasp. Which is OK for a beginner, if it were not the fact you want to play with high voltages. I mean, in this last reply you mention 15KV, the highest number yet.So apart from this last closing remarks, I am going to stop guiding high voltage responses:Do reconsider. But if you must persist, take RJHayward advise on a clean and non cluttered working area. And if you must use high voltages, at least keep the energy levels iow, meaning keep the capacitance values low. This stuff can really hurt you.Now, if you want to continue getting advice on low voltages, no problem. Like I mentioned before. see if you can boost 12V AC with a generator to 50V or 80V. If you want to understand electronics, that is just as impressive and you will learn just as much. Also it will make it a lot simpler to get the correctly rated components. Even if you want to eventually get to the big arcs, you need to build understanding first. If you just want to see big arcs from the get-go... well it's just not the right path.Quote from: zeal422 on June 01, 2023, 02:17:45 pmYou see, this is one of the replies that worried me. I said it jokingly, because everyone has already done the 555. But apparently not you yet. You just want to see sparks

author: zeal422
author_rank: Contributor
timestamp: June 02, 2023, 06:55:33 am
content: Thank you all for the replies and concern, It is understandable, although I want to clarify some things.First of all I will do this circuit with or without the help here, I know this sounds harsh because some people here genuinely helped and I appreciate every little bit of it, thus the reason why I join the forum in the first placeI do have this mentality of when I put my mind to something I will do it, everything it takes. Which in this context I understand the dangers of it and I've specified that in the previous replies. You are not responsible for my own doings, that should be logical. Even tho I am a beginner / hobbyist I am very aware of the dangers as I said it above and now repeating myselfThe amount of voltages from what I've posted above at 1kV has so low amperage that can barely hurt you, it's like a piezo electric from a lighter. That is why I tested this on my cluttered bench because I knew there is no real risk for human danger. When I up the input and add the new diodes and caps will test it on a big empty wooden table with a switch far away from it. Because that's what a reasonable human would doI really don't pick out what I want to hear, maybe the language barrier is part of it but I don't think it is. I do have a goal, and that is as you said at the end "You just want to see sparks" and that is the actual goal, yes. Big boy sparks and as I said in the beginning will do it regardless of the concerns from you guys (which again I want to mention that are very much appreciated)... I'm not saying this to insult anyone but this is my mentality. And I thought I might as well ask for help from more knowledged peeps so I can do the project safely and to the accurate values this one requests so everything will be in parameters.And maus, you said to try and bring 12VAC to 50V and I did, I said it in a previous replyAlso what capacitance should I go with ?So can anyone tell me why the inductor at the start, please ?Thank you all again for the input and concern, and again if you have advice for the project, I will very much appreciated it. If you want to close this thread that is also ok. But I will still continue the project, I just want to build it safely with the right components and will promise for now to only go to 5kV as a starter. Hehe, imagine ending it like that with me saying 'only 5kV' now you are all angry at me again

author: joeqsmith
author_rank: Super Contributor
timestamp: June 02, 2023, 02:55:58 pm
content: For 14, you could try to find an old NST, maybe along with a variac.

author: zeal422
author_rank: Contributor
timestamp: June 02, 2023, 03:16:35 pm
content: Hey Joe,I've looked to find one but they are quite rare, or maybe now they're made on PCBs instead of chunky transformers. Also I'm not ready yet to test it with those sort of transformers because these can easily kill you, so I'm trying to get some sources for the input that don't produce that many amps, because 30ma is enough to kill you, so I'm trying to test it with lowers amperages for now. Thanks for the suggestion. I might try it with one of those cylindrical 'stun gun' transformers you see on ali or on amazon, but then again I've heard that if you use them more than 5 seconds they could arc inside and destroy themselves, so I have to look for something else as less deadly as that one. Now I'm waiting for the diodes and caps to do anything. I've simulated some more configurations and 10nF should be sufficient, from my simulations at least.Cheers!

author: joeqsmith
author_rank: Super Contributor
timestamp: June 02, 2023, 05:48:34 pm
content: QuoteTrue, that 30mA 60Hz could certainly prove to be a lethal combination. Consider my gas grill ignitor is well over 10kV as well and can put Amps through you. Yet outside of trying to eat the thing, I don't thing it's all that deadly. I assume anyone working with potentially lethal devices (driving cars for example) has the education to go along with it.You could use an ignition coil and run at higher frequencies. Nice thing, they are easy to source, reliable, can operate for extended periods (much longer than 5 seconds), cheap and easy to drive. You can easily get 14. You could still string some diodes and caps on there if you want to play with DC. You could increase the capacitance (increasing available energy) if you want to add to your risk.

author: zeal422
author_rank: Contributor
timestamp: June 02, 2023, 06:39:09 pm
content: Thanks for the reply mate, and it's 50hz here in Romaniaalthough, If I straight up wanted big arcs (and deadly) I would've used a MOT, diode and cap that comes with a microwave oven, and using a ballast to lower the amperage, I've tested it, got scared a bit just from the sound of the arc (for good reason) and then drilled the secondary out of it and made a spot welder out of it that outputs around 1200 amps at 1.8V. Because I wanted to spot weld a lithium pack. Used a contactor and a relay to limit the time the circuit is closed so the batteries don't explode in my face.The point is that I want big arcs through this circuit, it's just so simple of a circuit, yet so intriguing. I know I can just get many mots, put them in series and some in parallel, connect more caps and you get huge arcs, or buy a distribution transformer and make deadly arcs, but that is not the pointRegarding the ignition coil... I have searched for some in my country, and on ali... but cannot really find the one ElectroBoom showed in his video for example, that type. Can't seem to find one of these. And don't know how are the new ones. Evidently I can connect the ignition coil to the circuit and produce huge arcs, but for that I need really good isolation, like epoxy and I don't have a vacuum chamber in order to draw the air bubbles out of the epoxy to make it 100% enclosed. Which... sucks. For now I will try 10nF 14kV because I've already ordered them, but I will not get to that amount, I will try 5kV first.Small edit: Would pointy thick solid copper wires as probes help with better arcs ?Thanks again for the input

author: joeqsmith
author_rank: Super Contributor
timestamp: June 02, 2023, 11:50:24 pm
content: I did a search on his channel and see that single output car coil. I use the 2-wire type at home for experiments. They are common here.When searching, he shows a Marx generator. If you want some big arcs, you should check that out.

author: RJSV
author_rank: Super Contributor
timestamp: June 03, 2023, 01:08:58 am
content: (Same concerns):You could obtain a nasty shock by way of your meter (not HV rated), when you touch the selection knob for example. You don't have a clue about limiting current, stating that it's safely limited at whatever 15 kv or whatever flippant ignorant statement you are issuing at the moment.So, how again does a multimeter cross leakage or insulation breakdown limit current, then?Worse than your individual trainwreck, is when you start 'teaching' others.Let us hear, please, your take on UV damage to eyesight, from Arc sourced light ? Of course, you likely have no UV protection.How friggin irritating with your arrogance

author: joeqsmith
author_rank: Super Contributor
timestamp: June 03, 2023, 03:55:12 am
content: Electroboom's Marx generator is pretty fun but here's a monster homemade one.

author: zeal422
author_rank: Contributor
timestamp: June 03, 2023, 05:54:42 am
content: That's just nuts Joe.Just the way he got that close to it to start it, is terrifyingI wonder the applications for such generator, I'm sure there are some, maybe in particle accelerators, but 100% not for my projectThere are also some quite nice arcshttps://i.imgur.com/gyZ1QsT.mp4Driven by an X-ray transformer and a full-bridge2 X 7 stagesInput voltage: 20kVFrequency: 11KhzOutput resistor:280Kohm + 600Kohm on each towerGap is 105 cm

author: Simon
author_rank: Unknown
timestamp: June 03, 2023, 09:59:15 am
content: Just ensure no one else is around and you tell your family not to tough you in the event of an accident and just leave the house until the fire brigade arrive. If you want to risk your own safety that is up to you, don't risk others.

author: zeal422
author_rank: Contributor
timestamp: June 03, 2023, 12:28:27 pm
content: Thanks for the concerns Simon.I do have a GFCI for these events if they do happen, and I know these can not 100% protect you, I am aware of it and the dangers. I never got electrocuted by mistake (so far) only on purpose. And I do want to keep the record straightCheers.

author: joeqsmith
author_rank: Super Contributor
timestamp: June 03, 2023, 03:45:29 pm
content: Quote from: zeal422 on June 03, 2023, 05:54:42 amThat's impressive. Of course there is always that big Tesla coil in Oklahoma. I'm sure by now someone has built something even more impressive. I wonder what that guy is up to.

author: zeal422
author_rank: Contributor
timestamp: June 03, 2023, 06:57:53 pm
content: That's I think the biggest tesla coil I have ever seenThat's more than impressive!Of course I too follow the one hand rule or the 'pocket hand', never touching with both hands. I too made a chicken stick from PVC (weird name, I have to find out where that chicken stick name came from), one with a 30W load resistor so I can discharge big caps without sparks and one just a isolated conductor for sparks.Unfortunately I don't have the resource to get a NST here, you have to know somebody in the domain. I will look for other alternatives.I want to see some of your builds if that's possibleAlso I bet your wife is not worried at all (sarcasm)

author: zeal422
author_rank: Contributor
timestamp: June 12, 2023, 08:19:59 pm
content: Small update:I didn't have the time to thinker more because of work but I finally had some free time to test if the 5kV HID / HPS ignitor would work as a driver, and it seems to do it's job.https://i.imgur.com/YmdT9vr.mp4Now all that remains is to wait for the HV caps and diodes from China and build the circuit, encase it in... I was thinking a PVC pipe with screwable caps, fill the thing with mineral oil, maybe johnson and johnson, and seal it up.Will update as the project goes further

author: zeal422
author_rank: Contributor
timestamp: June 15, 2023, 07:56:57 pm
content: Update:https://i.imgur.com/sbpy7JL.mp4I got my hands on 2 flyback transformers and finally found the primary and the ground on these... that took a while... Now I just need a bigger driver because what you see there is just a pewny CFL circuit board from an old flourescent lamp bulb. Chat GPT told me I cannot drive a flyback with that... Well robots are not there yet.Now I wait for the diodes and condensators... still, and we shall make the big cockcroft... accent on croft.