How to Make High Voltage Capacitors - Homemade/DIY Capacitors

[@521cjb]

Breakdown voltage ratings also include a time factor - a cap that can hold X volts for a few minutes may fail after a few hours, day, weeks or months. The book ratings are for dielectrics that can hold indefinitely. Supposedly. I've replaced many factory made caps that were rated for higher voltage than their actual situation in-circuit. Nothing is foolproof, and everything has a lifespan. Thanks for a great video, very informative.

[@hadleymanmusic]

This is one reason why home made time machines are dangerous the reliability of the caps are a safety hazard

[@angeloc700]

Seemingly, the information available to a curious mind in the 21st century is bounded only by the knowledge available by man. Thanks for posting!

[@1HayesEng]

It’s refreshing to find someone on KZbin who knows what he is doing..

[@TheKingofRandom]

Great video! Thank you!

[@maxwelledison1464]

The King of Random RIP

[@mykulpierce]

@@maxwelledison1464 seriously what a find. Rest in Peace grant

[@roykoffi7942]

Genius squad 🙂.RIP The King of Random. ❤🙏

[@johnnycash4034]

RIP Grant

[@Chemanic1]

Rip grant

[@RimstarOrg]

Thanks for the feedback. I'm glad to hear you're enjoying them and super glad to have helped.

[@999manman]

WOW!!! I had no idea this was even possible on a kitchen table level!!! Great video, Rimstar! I am floored!!!

[@RimstarOrg]

Interesting take on it. I gave basics like talking about breakdown voltage and how to figure out how thick to make it for a desired breakdown voltage and how to test it. I gave basics on materials like wax and resin for insulating and avoiding sharp edges and why. And I did show you the steps for one with two copper plates starting at 7:28. But I guess this is more of a "all you need to know to make one of your own design video" than I "step-by-step only for one capacitor video."

[@Taran72]

Finally! a video that shows me how to make a homemade capacitor that actually works and I can make from materials that I can find easily. thank you very much.

[@victoryfirst2878]

Congratulations Sir. This is the best video on capacitors making I have seen on KZbin. Nice work fella.

[@tompeterson9607]

The online rating is probably dependent on exposure time, if you were to do a longer running test at a bit of a lower voltage you'll probably find that the plastic will degrade and breakdown.

[@RimstarOrg]

A capacitor won't help you get from under 12V to 50kV. For that you'd need a high voltage power supply or some minimal circuit. Also a Van de Graaff generator or Wimshurst machine will do. But a carefully insulated capacitor like the two I show at the beginning of this video will hold 50kV once you have the high voltage power supply to make it. See the links in the video description for various high voltage sources.

[@rogeronslow1498]

The dielectric strength of a dielectric such as Mylar decreases as the film thickness increases. This means that you can't simply double the dielectric thickness and expect double the breakdown voltage. If you download the datasheet for Mylar you will see that the dielectric strength decreases substantially as film thickness increases. The reason is that the electric field does not distribute evenly across all the layers of dielectric film. A solution to the problem is to use a technique refered to as dielectric stratification. This involves placing floating tinfoil between every layer of film (but not right to the edge). This stabilises the electric field between each layer and allows you to stress the dielectric to it's published value. Also, you have to test the capacitors in oil if you work above the corona inception voltage (about 10kV) or they'll fail from corona and not dielectric breakdown.

[@50hh05]

this is a very interesting (and logicaly explained) piece of information but i cannot find any source for "dielectric stratification". Is there another term for it ?

[@johnrouse6957]

Thanks so much for taking the time to share your knowledge and build skills/ design ideas. I'm currently working on building my own capacitor discharge device for magnetizing. I want to experiment with a diy foundry and try some different alloys etc. the goal is to use raw materials/ easily attainable materials for alternative energy experiments. I can't thank you enough for your videos!

[@RimstarOrg]

+John Rouse That sounds like a great project, made up of interesting sub-projects, like the foundry. Have fun with it, and thanks for watching!

[@Eddygeek18]

Im very new to electric applications the most i have done is built a small kinda hovering motor thing using very basics like a motor an ac 16v adapter and a few cables with propeller blade mounted to the motor. I found this video extremly interesting and it has definatly expanded my knowlage atleast abit. Thank you great video :)

[@alocin110]

One of the best video on capacitors, capacitor testing, and workable design. Thank you so much for sharing your knowledge with others. \keep up the good work. Your lab set up is so professional that tells you have a good hand-on experience. Thank you again. I liked your video.

[@RimstarOrg]

For voltage you can use a meter with a suitable probe. In this video, since I'm measuring high voltage I'm using a high voltage probe connected to my analog multimeter. Some meters, like my Fluke digital multimeter, can measure capacitance. You can see me do it in my "How to Make Capacitors - Low Voltage Homemade/DIY Capacitors" video at 5:01 into it. There's a link to that video in the description below this video and you can find it on my channel page.

[@RimstarOrg]

You're welcome! And I never get tired of the feedback, so thank you. Yeah, capacitors are my favorite electronic component. Go electric field!

[@MotherRussiaisforever]

When the current is off the scale how much is the max on the scale?

[@RimstarOrg]

To get those ratings I just did a google search for the dielectric strength of polyethylene. If you do that you'll find a bunch of tables on different websites. All they say is "polyethylene", nothing about any grade. So I don''t know what grade the numbers were for. Also, for mine all I know is it's used for putting on floors under carpets to act as a vapor barrier. And thanks, I'm glad you find my videos and website helpful. Sorry about speaking fast.

[@AssExtinction]

Thank you for taking your time and replaying. I really do enjoy your videos about capacitators.

[@RimstarOrg]

Thanks! That's partly why I like making these videos is to show just what's possible on the kitchen table level. You'd be amazed at what you can do.

[@RimstarOrg]

+Nathaniel Charles Put a resistor in the circuit in the discharge path. PS There's no Reply button under your comment because of your Google+ settings. - go to your Google+ page, - in the top, right corner click on your thumbnail icon, - in the popup that appears, click on "Settings". - for the 2nd question down "Who can comment on your public posts?" set it to "Anyone".

[@gametrue2229]

RimstarOrg ?

[@sadunnakipoglu9471]

Thank you and appreciate your effort. Greetings to you from Turkey .

[@Slider2732]

Great video, learned a lot there. Heck of a bang a few hours ago here, from a substation a couple of blocks away. The power dipped off in the house and a second later heard the boom...I bet they were down to 1 sheet after watching your video LOL

[@bandoman59]

Great now I'm gonna be spending lots of time watching your vids. Even though I understand electronics. Been in it for years, still amazed by the physics of it all. I think you do a great job on explaining and showing it all also. And lastly you just helped me out with a project I've been working on.

[@JustinHallPlus]

I saw a really cool video where a capacitor made of a glass jar, and two pieces of foil was charged. The foil was removed while it was still charged, and then touched together with no discharge, however when the foil was replaced the capacitor was still charged. This shows that the charge is not held on the conductor, but on the outside of the dielectric, at least with a simple leyden jar.

[@RimstarOrg]

Justin Hall Yeah, the charge is sprayed onto the dielectric as the metal electrode is removed. That might have been MIT's video or that might have been my own video. Here's mine about dissectible capacitors kzbin.info/www/bejne/nYG7p2NsaLRoeJo

[@JSambrook]

I’m working on a magnetic loop antenna for 20m. This video is super-helpful. Very well done. 73 and thank you, John, KJ7RDV.

[@RimstarOrg]

Absolutely, the shape makes a difference. That's what I was trying to illustrate in the video at 6:00. What you're seeing with your wire is what I'd expect you to see. Try it with flat plates and you won't break it down as easily. I don't have any derating factor. I doubt that you'll find derating factors for breakdown voltage. You can find breakdown voltages for different materials, but they're tested with standard shapes. To know for certain with your plate shapes you just have to test.

[@dalenassar9152]

After looking at your page on making high voltage capacitors, I thought that you MUST see (if you haven't already) the standard on making a simple splice (to connect two wires together) to NASA specs.It would go very nicely with your connection and it is ULTRA-SIMPLE...just about five or six simple requirements. Also, now I see that it looks like it is designed to prevent corona leakage...a way I never looked at it before seeing your link. I don't have a link (there are many) at the moment, but you can just google the likes of "wire splice to NASA standards" or "linesman's splice to NASA standards"...etc. This is something everyone from the beginning hobbyist to professional electrical engineers must see!

[@RimstarOrg]

The technique I use, the one I show a bit of in this video at 8:55, has worked well for me up to 75kV and high current without measurable leakage. I talk about it more on this page rimstar.org/equip/hvwiring.htm. But mine is more for temporary connections, sort of a way of plugging and unplugging high voltage components. The NASA one looks great for permanent connections. Thanks.

[@directeeccks]

This is a very good video. You sir get a tip of the hat on the detail you went into. This information is really good for eco types. We could upcycle what most consider trash to this. Good work sir!

[@RimstarOrg]

You can find details in the Equipment section of my website, rimstar.org. Look for "30kV DC power supply (homemade)". I also just put a link to it in the description below this video.

[@RimstarOrg]

It's used for this purpose quite a bit; it wasn't my idea, I was just following common practice. From wikipedia it's used "in transformers where it is known as transformer oil, and in high voltage switchgear where mineral oil is used as an insulator and as a coolant to disperse switching arcs." It's not considered flammable because its flashpoint is above 100F/38C, but is considered combustible for the same reason.

[@RimstarOrg]

I got it from a carpet store. They used it as a vapor barrier under carpets. Though it might also be used in walls during construction for the same reason.

[@JamesBiggar]

great info! nothing helps me to understand something better than watching someone break it down or build it, thx for sharing! could the thickness of the polyethelyne be causing the discrepency between your test and the breakdown info that you found online? general purpose poly is quite thin, whereas construction poly is many times thicker. the poly you used seemed quite dark like construction poly - maybe it's thicker than the poly that the site gave a rating for?

[@RimstarOrg]

If you mean the place in the video where I'm showing leakage at one of my connections (5:32) those are positive ions since they're at the positive wire. I don't know about positive ions being toxic but I know ozone can be produced in this way. Ozone gives off a pale blue light. It's not an ion since it's a molecule of three oxygen atoms. Ozone can be harmful in over a long period of time. My test was pretty short but anyone exposed to it a lot should do so in a ventilated room or outdoors.

[@RimstarOrg]

+Sanskruti Mohanty I'm assuming you're referring to when I said "1 mil = 1/1000th of an inch". The mil I'm referring to is not the metric millimeter. See en.wikipedia.org/wiki/Thousandth_of_an_inch.

[@caseyd471]

So in order to make it larger do I just repeat the layering process? |\|\|\|\|\|\|\|?

[@RimstarOrg]

That depends on what you mean by larger. To get a higher capacitance you want less layers, but that means it won't be able to withstand as high a voltage. And vice versa, to make it able to withstand a higher voltage without breaking down you add layers, but that will result in a lower capacitance. You need to figure out what your capacitance needs are and how high your voltage will be and then go from there. This video talks about the voltage part, the capacitance part is talked about in my other video kzbin.info/www/bejne/fafIemydja6mftk.

[@dfraldas]

Oh yeah! Corona dope for the corona pandemic time is the best combo!

[@JamesBiggar]

just checked out the video again - with coffee in hand - and noticed the 'volts per mil' chart, lol. don't mind me

[@RimstarOrg]

I can sort of understand why. Repetitive pulses wouldn't give the dielectric much time to relax between pulses. It's probably pumping up the energy in the dielectric.

[@jerryuhte1284]

That is so clever om, i built a 20 m cu loop but never could get it to resonate ! I had coax and a split rotor cap , never did figure out why ! You have hit on something ! Lets hear it work ! 73 K9UT Jerry Uhte

[@RimstarOrg]

You're welcome! I really appreciate you're watching it! So thanks right back.

[@ericbelistan6591]

Big thank you from France. Your work is very interisting and well explain. Eric

[@forrestmorgan3222]

Sir You are Genius. I wind large Ruhmkorff Coils, and started with Layered, at 9 years old. My Coils work fine. Finding the "best" capacitor, is more trial and error then math. Oh to have a brain like Yours.

[@RimstarOrg]

Since you're using AC and not DC, the capacitor is being constantly charged and discharged and with alternating polarity. I suspect the vibration is the plates being attached to each other when charged and then relaxing when discharged. The way I suspect there's a loss is that since the plates are free to vibrate a bit, they must not always be as close as they can be. If they're as close as they can be then they'd always have as high a capacitance as they can have.

[@saturn5tony]

To quote the fellow from vulcan..... Fascinating!

[@TheFecesGuy]

saturn5tony are you out of your Vulcan mind -McCoy

[@RimstarOrg]

Good idea. Thanks. Much, much bigger topic than capacitors though.

[@RCengineFAN]

Thanks for getting back to me. Will keep that link.

[@RimstarOrg]

Thanks. I'm glad you like the video. I'll leave it to you to do the dielectric strength tests... now that you know how! :) Make sure to put up a video of the tests. No kidding I'm busy too. Woke up in bed this morning going back and forth on the details for three different videos!

[@roccotinitali1544]

I admire you and your experiments. Thanks for your efforts sir.

[@RimstarOrg]

The sell them in sort of large rolls here too. I have a roll that's around 80 centimeters tall but I don't know how much area is rolled onto it - a lot.

[@vickyheriyantodarmadi6469]

Very good video, very easy to understand

[@bertbronson8395]

IDK if your PE is 94-v rated, but if not, PE turns to liquid fire (imagine water on fire and running everywhere all the sudden) if it catches fire... big deal around electric applications. This is more for the impatient experimenters viewing this in case they decide not to encase it like you do.

[@Landotter1]

As an addition, you may consider showing how to make a HV tesla coil capacitor/s to form a bank for the proper value... series/parallel, etc. I made one 20 years ago with thick polyethelene sheet and aluminum flashing submerged in mineral oil bath in a piece of 6 in. pvc... Sadly, i never got to build my coil and gave the thing away...

[@RimstarOrg]

I just checked. It's 13 picofarads. And thanks! I'm glad you liked the video. Thanks for watching!

[@Bashnja1]

At only 13pf it has very limited useability, to make a useable value of several hundred or thousands of Pf the thing would be unmanageably large.

[@burkegreg]

My new favourite channel

[@RimstarOrg]

Thanks! I hope you enjoy the videos.

[@Ezio-Auditore94]

Awesome video, well documented and explained. Just awesome

[@RimstarOrg]

No. If the breakdown voltage of polyethylene is 500 volts/mil and the polyethylene is 20 mil thick then it can withstand 500 volts/mil x 20 mil = 10,000 volts. If it's 40 mil thick then it can withstand 500 volts/mil x 40 mil = 20,000 volts. So the breakdown voltage increases as thickness increases but the breakdown voltage per unit of thickness (mil for example) stays the same.

[@RimstarOrg]

Oh interesting. I never noticed that before. Even the wikipedia page says "it decreases slightly with increased sample thickness." Almost sounds like there should be a volts/mil/mil value or something.

[@RimstarOrg]

You're welcome and merci, Eric. -Steve from Canada

[@RimstarOrg]

If the power supply is disconnected from the capacitor so that the capacitor is on it's own, then yes, it holds the voltage, though like any capacitor, it loses some over time. If you just unplug the power supply from the wall, then in this case it also holds the voltage. Some power supplies, when turned off, would allow a path to discharge through the power supply.

[@RimstarOrg]

I won't make a video of it but what capacitance are you trying to get? How much voltage? A low inductance mineral oil one is tricky (on first thought) since for low inductance you'd want to connect along the entire length of each capacitor plate, not just at the ends of the plates. Since for mineral oil you'd likely be submerging the plates, only one end would be sticking up.

[@RimstarOrg]

Not directly. A battery puts out direct current (DC), a steady flow, one-way, uniform flow of electricity. A transformer needs current that's constantly changing such as alternating current (AC). You could, however, add some circuitry between the battery and the transformer to change the DC to AC before going into the transformer.

[@ArtyMars]

This was ten times as informative as i was expecting, thanks hahaha

[@RimstarOrg]

Cool! Looking forward to what Buddy has to say!

[@paulojesus8573]

This was sooo good man Thanks alot Good infos Old video but aloot of good infos Working to make graphene capacitors and this video help me to make good ones

[@hartyguyton3800]

You are phenomena ^_^ . it is illustrated in High Professional way. Keep going!

[@RimstarOrg]

Thanks! Welcome to my channel!

[@Deliriousintentionsprojects]

Wonderful description and testing. Good work! well done.

[@ikel6253]

It's funny when u type of people make these video's, and explain/show thing's like we all have these electrical instrument's/machines in our kitchen etc... And ur speedy talk like were all robot scientist's!

[@999manman]

Most appreciated....I shall look them up...sadly, our local Radio Shack just turned into a US Cellular store..sigh....

[@TheSecrecyOfFrequency]

Kapton / Polymide for a 10-20 x Higher Voltage per mm alternative to polyethelene. Great video thankyou.

[@mitchellrose2940]

you're the best...you must do this for a living.

[@mundymorningreport3137]

I read that the higher the voltage, the smaller the gap between plates... something to do with the odd fact that higher voltages actually form smaller fields. You can't really serially stack dielectrics and expect them to hold up to the total high voltage, each dielectric will be hit with the total voltage.

[@RimstarOrg]

Thanks. I'm glad to hear you got something from it.

[@MongrelShark]

Good video! Very informative. Thanks for uploading. Could I request you test the dielectric strength of some common household materials. Like Cling wrap (good quality and super cheap), Disposable cups (plastic and polystyrene), Plastic freezer bags, Rubbish bin liners etc etc? I'll be doing some more testing with Cup-caps and some other ideas sometime, First I need high voltage. Few other things on the go. I know your busy too. Look into lanolin oil if you get a chance. Keep up the good work.

[@RimstarOrg]

Ah, thanks for clarifying. And I agree that adding layers of insulation between the electrodes changes the capacity. But if you're going to be using a certain voltage range then your capacitor will have to be able to handle those voltages. Since it affects the capacity, you'll have to change something, like increase the surface area, to increase the capacity at the same time. That's why at 1:11 I refer to my video that talks more of the variables.

[@TrashcanScienceStuff]

hi first thank you for the simplified explaination that i could not have found anywhere else on the internet, and i have a question please, that capacitance formula is there a similar formula for batteries i am trying to make a salt water batterie using zink and copper electrodes and i wonder if there is a similar formula to calculate the estimated capacity and voltage 🙏🙏🙏 and thank you

[@RimstarOrg]

Thanks! I'm glad you found it helpful!

[@morganchandler5126]

RimstarOrg hello I'm not sure if you'll ever see this or reply but I'm working on some things and I would like you input... a high voltage project

[@RimstarOrg]

You can definitely find it, but just made by a different company. It's use in electronics for helping prevent voltage breakdown. Look in electronics stores and electronics supply websites for "corona dope". It has a very high dielectric strength/breakdown voltage. Look in electronics stores and electronics supply websites for "corona dope". I just put a link for you in the description for this video to the webpage of the manufacturer, MG Chemicals, part number 4226.

[@OK2BCK]

videos like this are VERY appreciated, thanks!

[@MrVaneurin]

Tanks for the very educational video, well done.

[@Travelbeatcreations.official]

Hi, would You be able to check out how graphene performs and if it can be a possible replacement for traditional car batteries?

[@Rico702Vegas]

The polyethylene.. I saw the rating for it was 481-551, does this include the range for all grades of polyethylene? Was your plastic high grade? I really like your website man, and although you speak a little fast for me (novice at this stuff) thank God for videos and the pause button lol. You are very appreciated sir.

[@RimstarOrg]

Glad to hear it. Thanks.

[@mathhuemcmahon]

Awesome videos. Would you be able to do a video of what's inside a microwave ac cap?

[@RimstarOrg]

You may be new to electronics but it sounds like you've done some cool stuff. Thanks for watching!

[@badassredskin]

Great video. You just got a new subscriber!

[@jimawhitaker]

Thanks for the video, I just subscribed. I'm here after blowing 3 cheap Chinese 1000 nf caps and deciding either I'm going to spend way too much or build some myself. I found some teflon sheets used in heat transfer I'm going to tray as my insulator. Do you have any experiance with that material?

[@bryantlarsen4462]

Thank you for your great videos. They are well planned, thought out, and explained so people can easily understand them. I have a question regarding home made capacitors. When building a capacitor, which is the bigger limiting factor - the plates or dielectric? Meaning is the size of the plates a bigger requirement to meet certain parameters? or the dielectric? Also, If I build a capacitor for a certain use, and the voltage is higher than what can be handled, do I just put a resistor and fuse to limit the power? For example, I build a 200V capacitor, and use it in a circuit with a 50V motor. Do I put a 50V resistor and maybe a fuse to limit the power to the motor? I am new to the details of electronics. I am informed enough on building off the shelf stuff, but individual circuits and components are a new world to me. Thank you for your help! I really appreciate your helping people with your videos. I watch them first, research more so I understand it better, then show my kids.

[@RimstarOrg]

+Bryant Larsen Regarding the limiting factor difference between plates and dielectric, it depends on what factor you're talking about, capacitance or breakdown voltage. You can see all the things that affect breakdown voltage in this video (I won't repeat it all here.) Capacitance is determined by a mix of things which I go over in my other capacitor making kzbin.info/www/bejne/fafIemydja6mftk video. If you build a 200V capacitor, that just means the capacitor can handle 200V before it breaks. It doesn't mean you'll be charging it to 200V; that's up to your circuit to do. If your circuit can produce only 40V then the 200V capacitor will charge to only 40V.

[@RimstarOrg]

Thanks! And welcome!

[@raffmaxi]

Hey, I'm looking for a cheap replacement instead of expensive professional capacitors for my Tesla Coil. What do you think? Is it worth a try or should I invest in the expensive ones?

[@greenthizzle4]

raffmaxi try bucket capacitors, they will last the longest and are cheap to make.. well if you got room at least, I personally don't have room so I'm not using them. I was thinking of making my own with copper plates and mica layers to insulate.. you can get mica out of old microwave ovens, they use them on the wave guide.. there are normally alot of people getting rid of microwaves.

[@RimstarOrg]

You sure could. I never thought of that.

[@ExoticHacksXD]

thx for the reply but i was really aiming for what type would be best for a Marx generator

[@StevenSesselmann]

The breakdown voltage should hold for instant on and instant off, ramping up the potential slowly will yield a better result.

[@SirArghPirate]

Very informative! What do you use the capacitors you make for?

[@ExoticHacksXD]

what would be the best kind of capacitor to make to charge to a very high voltage then release that energy. basically use a AA battery (or any dc voltage under 12v)to charge to 50Kv

[@RimstarOrg]

Thanks! Glad to hear it!

[@jjmirks]

Do you know the capacitance of your square capacitor in the beginning of the video? Awesome video by the way, I really enjoyed it. :D

[@jimawhitaker]

Thank you sir, I have been wondering how people are measuring currents from things running at 20 kv+ with regular multimeters. Right now I don't own and analog meter but could buy a cheap one just for this. By the way I really like the old Radio Shack meter. At one time they actually had good equipment. I have one of their digitals that was made by Fluke :-)

[@antoniorioscortes2766]

Hello, very interesting, can you tell me were can I find how to calculate to make a super capacitor that substitutes the battery of my car? it would have to support 15 volts and at least 1000 farads, is it possible?

[@fly5648]

ebay m8

[@999manman]

I am fascinated by this science but know not where to start...I just got my first multimeter last year and have been doing things like measuring voltage drop on my home wiring when the furnace cuts on and measuring the ohms of my guitar's pickups...I'm pretty much a book learner so can you recommend a decent starting point? I've seen a few interesting titles on amazon like Make: Electronics and There Are No Electrons....any insights?