How a Van de Graaff Generator Works
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- Опубліковано 26 чер 2024
- Detailed explanation down to the electrons and protons on how a Van de Graaff generator works. Includes the triboelectric effect between the rollers and belt, corona discharge and photoelectric effect between the belt and brushes/combs, and Faraday ice pail effect at the top dome/bowl. Shows how arcing/sparks happen and how strong electric fields contribute to creating ions and plasma for making air gaps electrically conductive.
This video has correct English captions. Click on the CC button at the bottom of the video to see them.
See also, Triboelectric effect/series or triboelectricity:
• Triboelectric effect/s...
How to Make/Build a Van de Graaff Generator Part 1 (Homemade/DIY):
• How to Make/Build a Va...
Magnetic field using horseshoe magnet, keeper and iron filings:
• Magnetic Fields, Keepe...
I purchased the big and small Van de Graaff generators from Information Unlimited many years ago:
amazing1.com
The big one is made and also sold by Science First:
www.sciencefirst.com
I don't see it any more on their website but they have others. They also sell spare belts but don't say what they're made of.
To see how to make your own Van de Graaff generator:
rimstar.org/equip/build_make_v...
Follow me on Twitter:
#!/RimStarz
rimstar.org - Наука та технологія
Thanks! I'm glad you liked it. It was a lot of work so your feedback is appreciated.
-Steve
Excellent video! You are the only person on UA-cam who actually explains this. Thanks a bunch!!
Absolutely agree with you. I have watched many videos about this topic, no one can explain how the positive charges accumulate on the outer surface of the belt, but he did.
I'm glad my presentation helps! Thanks for letting me know.
Finally, a person who explains this in detail! I don't get why other youtubers explain the Van de Graaff generator as a machine that simply collects electrons and they leave at that explanation, which is vague and does not really makes sense.
You're welcome. And thanks for you generous feedback. I'm kind of fond of this one myself but it's reassuring to hear it from others.
Wow! You're welcome! I'm delighted you liked it so much. And thanks for saying so.
Yes, you can use the same materials with a small homemade van de graaff. In fact the small one I show at 2:12 in this video has a Teflon roller at the bottom and a metal roller at the top and uses a rubber band for the belt. Using metal for the top roller is less effective than using something that's triboelectrically positive with respect to the belt material but the teflon and rubber band combination works so well that the results are still very good.
The charge is deposited using the triboelectric effect. When two particular materials make contact and then break contact, their molecules interact such that charge is exchanged while they are touching but doesn't get restore when the separate. The belt and rollers are constantly making and breaking contact. And yes, we are transporting the protons and electrons exactly like transporting materials on a simple conveyor belt. See my video Triboelectric video, see link in this video's description.
I'm glad you liked it, thanks. And welcome to interacting on UA-cam.
I have to agree with everyone - your explanation of how the charges move and where they're coming form and going to is perfect. This video needs to be made into a section in a physics or an electrical engineering text book, seriously. Thank you for laying it out. Your video is in my play list. I'm going to make a Van De Graaff generator too.
Thanks! And thanks for the feedback. It's good to know the explanation works.
Thanks. The section explaining how the Faraday cage works is a little contentious since I wasn't using the standard approach to explaining it with just fields. But I really wanted to do it at the electron and proton level; more tangible, and also consistent with the rest of it. Have fun making your Van de Graaff generator. Be sure and check out my videos on that topic and ask questions if you run into problems.
Just discovered you channel. I'm a fourth semester electric engineering student from Venezuela and this is just breathtaking for me. Thank you for the videos!
If you're not an educator by trade, you have certainly earned this educator's respect. Very well done.
Thanks. That's a big complement indeed. I spent 13 years traveling around the world teaching for a software company, I currently teach a few times a year for an adult education program, and have done other teaching and course development over the years. I can't seem to stop myself. :)
It's an insidious passion of mine, too, friend. Learn something new everyday, I say. It keeps Alzheimer's and boredom at bay.
You're welcome. I'm glad you like the videos. Thanks for watching them!
To understand Van de Graff Generator, I watched a lot of videos and this one was the most informative and useful one for me. Thank you for your effort! :)👏
Wow, this was so much more informative than I expected from a UA-cam video. Excellent video!
Thanks. It's a lot of fun (but also a huge amount of work) making these detailed ones. Two others which I'm proud of are How a Crystal Radio Works ua-cam.com/video/0-PParSmwtE/v-deo.html and How a Wimshurst Machine Works ua-cam.com/video/nA4aCd5qFWs/v-deo.html
@@RimstarOrg you didnt leave a single little question. every small details was explained. nce work. thanks.
This is the best video I have seen for some one who wants to understand the Van De Graaff generator. Thanks Rimstar.
I'm glad to hear it. I try to leave nothing to the imagination so maybe that's why my explanation works for you. Thanks for the feedback.
You're welcome. Thanks for the feedback.
Das ist eine gute "How to"-Anleitung. Interessant war die Verwendung von Isolierband für den Antriebsriemen und wie man es auf die Rollen legt. Danke für die Zeit und Mühe, diese Videos zu machen. Es hilft vielen Menschen und inspiriert sie, etwas aufzubauen.
Thanks. I'm glad to hear it helped.
@lx0199 I purchased the generator years ago as a whole from Information Unlimited (I'll put the link to their website in the video description.) The unit itself is made by Science First (again, link in the description or just search for their name) and was a slightly different positive charge version of their # 615-3145. I don't see any spare rollers for sale on either of their websites, though Science First does sell the belts. Contact them to find out what the belt is made of.
@JeanAlex23 Glad to hear it, thanks.
This is just simply an excellent description. A comprehensive class unto itself. The best on the internet. Thanks for your efforts.
Yes, by sharper surface I mean smaller in diameter.
Assuming 79kv between two domes, the smallest diameter dome has the stronger electric field around it. The air molecules will be repelled from the smaller diameter one, and be attracted to the larger diameter one.
And you're welcome. Glad I can help.
@sanches2 Thanks! My pleasure.
I gotta say you really did well on explaining this device, and even the effects that happen on the machine
@daytonharmon94 Thanks, and you're welcome. I do the best I can.
The triboelectric effect's video really helped.. Thanks a lot for helping and clearing my doubts :)
Thanks. I tried to make it as complete as I could for the popular types of Van de Graaffs at least.
Going to have to watch this many times. Very detailed. Thanks!
Great Great Great. Thanks. First time in my life to understand clear easy I try many channels at you youtube but you are the best
The upper brush is connected to the inside of the dome.
Is that what you thought, or did the video somehow lead you to think it was connected to the inside? If so, which part of the video made you think that?
Oh good, glad to hear it helped. Thanks.
Best video to clarify all doubts about Faraday cage etc.
By the way, which Myles? There seem to be two of them depending on if you include user in the URL.
Best explanation and the questions give better insight, thanks
You explain it much better than Plasma Channel
You're welcome. I hope my answers helped. Cheers.
Thank you for the video, it's the best explanation I found on Van Der Graaf generator, now I can build my own knowing how it works and why.
@aethersheep Great! I hope you aced it.
That's a perfectly reasonable question. A big use for them in the past was for generating high voltages, in the millions of volts, for particle accelerators for doing science experiments. I don't know if any particle accelerators still use them. These days they're mostly used in classrooms for teaching about electrostatics or by hobbyists who just like to play around with high voltages. Science museums also use them for demonstrating electrostatic phenomenon.
Great stuff, I always enjoy your videos.
Comprehensive video! Thank you for making it
its the best video on van de graaff generator..thanks for uploading it
Oh good. I wasn't sure I'd understood your question correctly. Thanks for letting me know.
Thank you very much for all the information! Helped me understand how to build my future Van de Graaff generator! (Already ordered the parts)
I searched hours for this explanation.. THANK YOU
even though I do not know English, the video is so didactic that I understood, thank you very much!!! from Brazil, translated by google translate hehehe
AMAZING!!!!! BEST EXPLANATION I HAVE SEEN!!!! THANKS SO MUCH!!
Thanks so much! This has helped my physics revision improve SO WELL x
Thanks! That's high praise; that's a good school.
Yes, the effect only charges the inner side of the belt. But the main reason is that the charge on the inner side of the belt is spread out over the larger inner area of the belt. The roller, however, has a smaller surface area and so the charge is more compact, the voltage is higher. So we use that higher voltage to pull more charge onto the outer surface of the belt. As a result, the outer surface of the belt has more charge than the inner surface. It's that larger charge that we're after.
my bad at english and your good at presentation make my mind blow :)) ho ho ho thank you. Such a good guy. Spend a lot of his time to help people :D
@ken25taylor Thanks, Ken! And thanks for the feedback.
your video is amazing it really helped to understand what a van de graaf genarator is
Very informative. I wondered how they worked. I just wanted to see how the dome was constructed and attached to the circuit. Thanks.
It's my first time to log-in my account to UA-cam. To like and comment to your video.
Very informative, thank you very much! :)
You're welcome. I'm glad I could help.
Very clear, nice and informative. Helps allot!
Wow this is an amazing video. I love learning things like this thank you so much for helping me understand better
Excellent explanation
So informative and visual. Thank you so much.
Such a nice video to study for Physics Exam!! Thank you!
Excellent explanation, thank you.
Wonderfull explanation... Thankz a lot..
You're welcome! I'm sure the little ones will be delighted. Have fun!
Wonderful explanation
If you have an ice pail with a large enough opening, you could put the terminal of an electroscope inside and the electroscope leafs wouldn't repel each other. If you're not familiar with electroscopes, see my video "How to make an electroscope (DIY)" (to help you find is it's one of my oldest videos.)
It's great explanation 👍
Awesome awesome video, thank you so much! Answered a lot of my questions I couldn't gets my heads around!
Superbly done.
Thanks! During the last days I have been trying to make my own generator without success. Your video helps me a lot to see why my attempt didn't work. Now I *finally* understand why there is some charge accumulation at all (ie, which is the origin of the first charge gradient).
Glad to hear it helps! Know how it works makes all the difference between engineering and guesswork. Let us know how it goes.
You' re welcome, and thank you.
Nice job , good explanation , a lot going on there
Thanks!
Great an complete explanation! Thanks a lot.
Man's replaying to comments 10 years later
12 years later, too.
Thanks a lot for the video and the detail
Yes. Air contains a number of different atoms. One I know for sure gets ionized negatively is oxygen, which can then attach to an O2 molecule to produce ozone (O3). I'm don't know offhand which ones get positively charged. I talked about atoms becoming ionized in the video but molecules (which are made up of multiple atoms) can also become charged.
Not usually. The electric field and resulting current flow are usually too weak. However, you can sometimes replace the regular multimeter probes with a high voltage probe to measure weak electric fields - by contact with the affected surfaces. You can see one of these probes in action in yet another of my videos :) "High Voltage Probe How-to with Fluke 80K-40".
That was so informative thanks for sharing.
Thank you for good clear information.
Thank you very much! Well explained
K, thx allot dude, this vid is great as well as the others on your channel. Keep up the good work :)
Both of my VDGs in this video were bought, I didn't make them from scratch. The big one was from amazing1 dot com. They don't sell the domes separately. A lot of people make the domes by attaching two steel salad bowls together at their open ends and cutting a hole in the bottom of one. After you make the cut, smooth out the edge; sharp edges reduce the voltage. Note that VDGs produce high voltage but not a lot of energy; the current is very small.
The motor has a power chord which is plugged into the wall socket to power the motor. That power chord has three wires: a black wire, a white wire, and a green wire called GROUND. That green ground wire goes through the wall socket and eventually to a metal rod in the ground in the backyard. That green ground wire is the one you see in the video at 2:04. The brush and the green ground wire are both connected to the metal case so they are connected together. Let me know if that doesn't help.
Very well done. Thank You
Great video. keep up the good work.
Thanks. I'm glad it helped. Yeah. as long as the connection is to the inside of the dome then you're okay. Connecting to the outside makes it much less efficient.
Great explanation 👍
that's amazing thank you so much for the video, it is a good explanation going into details. god bless you man
Thank you ... The Video is much informative and helpful..
Sorry, I don't know of a good website off-hand. I used my old high school physics textbook to double-check my knowledge of this.
My approach was to first make sure my understanding of the relationship between electric fields and voltages was right. They're proportional to each other, denser e-field = higher voltage. Then I reminded myself that a charged VDG dome is a capacitor, with the room being the other plate. Since voltages are the same, e-field is the same, affect on ions is the same.
I don't have a video on that. Though if you look at my "How to make an electroscope" video it's the same thing that makes the leafs inside the jar spread apart. If the VDG dome is positively charged then the hair is also positively charged and since like charges repel each other, the hairs all repel, getting as far apart as they can. Similarly if the VDG is negative then the hair is negative and repels.
Thanks. And thanks for subing.
(... continued) The same for a capacitor. The more charge you put on the cap plates, the stronger the electric field between the plates, the higher the voltage. The VDG dome and ground can be considered a capacitor. Pressure is sometimes useful analogy for voltage. By pumping more charge onto the dome you've built up the pressure. Bring a grounded ball close to the dome and the charge on the dome rearranges closer to the ball. The pressure may increase until the charge bursts across the gap.
amazing. your better than my physics teacher who went to oxford!!!
Kewl vids. I just subbed him. Thanks for the tip.