A neat thing you can do with a high voltage capacitor, usually a Leyden jar - take it apart, discharge the plates, put it back together and it still has most of its charge! Enjoy!
RimstarOrg I seen someone charge a bottle of coke with like a million volts on a RU-vid video and then they drank it and it looked like they got shocked I'm pretty sure it basically was acting as a capacitor
For the people that say they have never seen anything like this before, well if you ever heard of or used an electrophorus in school you have. A electrophorus is a dissectible capacitor. It is all caused by dielectric stress in the dielectric and the fact that dielectric will stay stressed for some time and can be made to stayed stressed for months if properly set up. But if this demo helps you understand more about charges and how they react in different materials, then this is good. BOB
Now we need some experiment to find out if indeed is the metal holding charges and not the dielectric only all along! This video made me come up with a question I have about capacitors in general: the usual thinking on capacitors is that we get a voltage between the plates and it will charge up (drawing amperes) until its voltage value equals the source of power. But, AFAIK, electrostatic machines will always generate little voltage, still a capacitor connected to them eventually raises an high voltage. Maybe these machines actually generate pulses of high voltage?
Regarding the dielectric only holding the charges all along... we know electrons are going to the negative plate, the plate is in contact with only some of the dielectric (in this case), so at most electrons would go to the dielectric there because electrons won't conduct across the surface to other parts that aren't in contact. So the dielectric alone couldn't hold all the charge. I don't know what would happen if you had a capacitor where all the dielectric was in contact with the plate though. I have heard of an experiment where if you start with too low a voltage then the charge stays with the plate since it can't reach high enough voltage to ionize the air. Regarding your general question, in a Van de Graaff generator the dome can build up a very high voltage despite the belt and brushes being at a lower voltage because of the Faraday cage effect. In a Wimshurst machine, the capacitors build up a high voltage because the charge on the opposite capacitor plates have opposite charges that attract each other.
It would be just the reverse of how to dielectric container got charged. When the plates are put back, there's not a huge amount of surface area in contact with the container so only a little charge would move to the plates where the plates touch the container (since the container is an insulator, charge doesn't migrate across its surface to where it touches the plates.) The real action, I think, happens when the two ends of the alligator clips are brought close together, the spark gap. That's essentially the same as bringing the two plates close together, or the inside and outside of the container close together, creating a high potential difference between the inside of the container, the inside plate, through the spark gap, to the outside plate and the outside of the container. That potential difference is great enough to cause the ionization of the air gaps between the container and the plates. At that point the remaining charge where the container doesn't touch the plates goes from the container to the plates to the spark gap.
I had this come up yesterday as a question to a proposed design! Glad you made this demonstration. I am making a Leyden's Jar with distilled water and graphene. The concern was that the graphene would settle in the water eventually without a additional binding agent, but I brought up this example! To my estimate you can simply shake up the graphene water and the charge should redistribute from the dielectric back to the graphene without an issue. Sound about right?
So if you do this then give grandma the glass with water in it her mustache will stand up? ;) As always an excellent video with great graphics. I love your channel.
That will still result in a charge difference between the two plates. The means there will still be a voltage and you'd still see an effect. It just might not be as large an effect.
So if you put a conductor in contact with both sides of the dielectric when its dissembled, does it neutralize the charge? Looking at your animation, I got an idea for a sliding capacitor step up transformer... Do you know if its been done before? I cant see it being fast or convenient, but an interesting learning tool maybe. I've been looking for a good video on this for ages. No doubt I'll be linking to this oftern. Great work as usual.
If you put a conductor in contact with both sides of the dielectric when its dissembled it may or may not neutralize the charge. Since a dielectric is an insulator, electrons don't flow freely across it. So to discharge the dielectric in that way your conductor would have to make contact with then entire surface of both sides of the dielectric. That's not an easy thing to do. I've seen a number of people experiment with capacitor transformers over the years. I don't recall any sliding ones though. I'm glad you enjoyed the give. Thanks.
jon sanford I'm not sure I made the point of the one in this video clear. It was to show that you can remove the capacitor plates, discharge them, and put them back and the capacitor was still charged, since the charge had moved to the dielectric. Another thing I should have made clearer is that you need a sufficiently high voltage on the capacitor, otherwise when you pull out the inner plate there won't be enough voltage produced to ionize the air and dump charge to the dielectric. If the starting voltage is too low then when you pull out the inner plate, no charge will go to the dielectric and when you discharge the plates, they will actually discharge. After reassembling the capacitor it won't be charged anymore.
jon sanford I was thinking about a capacitor that gets charged, then reduces the plate area. Lowering the farads, and thus forcing the voltage to increase to compensate for less storage volume.
Mongrel Shark There was a clever High voltage supply for a Giger Counter that charged up capacitors in parallel then switched them to series. with a printed circuit switch.
Hello. I have a question. 1. Why is the inner plate positively charged? I think, electrons are flowing into the recipient, so it should be negatively charged, right? 2. If you touch the plastic, Should it lose its charge?
Hi. 1. If you mean at 2:06, you're right that electrons flow into the plate but only enough flow there to neutralize some of the positive charge. You can see some of them get neutralized in the animation. There's still some positive charge that doesn't get neutralized. 2. I do touch the plastic in the video and it removes some of the charge, but not all. Touching a metal plate removes all of the charge because the metal is electrically conductive and so the charges can move around it to get to my hand. But the plastic is not electrically conductive, so the charges can't move around to get to my hand. That means that only the charge at the places where I actually physically touch it get removed. It turns out that it's very difficult to make physical contact with all of the surface of the plastic and so there's always charge left on it, quite a bit in fact.
Thank you very much. Just one more question left: 1. Electric field between one plate and the other it's capable to break through the plastic, even despite is not electrically conductive?
It's possible if the electric field is strong enough. In this case it wasn't strong enough. Searching for "breakdown voltage" or "dielectric strength" and the material your dielectric (the plastic in between the plates) is made of will tell you how many volts you need per thickness in order for it to break down.
+Andrew Kimble You'd need to make or buy an amplifier and then use the solar panel to power the amplifier instead of using batteries. For example, it could be done with my homemade amplifier here ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-JtPwxbOgBHw.html, though you'd need around a 9V solar panel.
+Akash Padhye When you touch one plate of the capacitor with your fingers then some charge will move from your finger to the plate but I don't think it will be enough to give a shock. For it to give a shock, there has to be enough charge to electrically break down the air just before you touch it and I don't think there's enough for that. At least not with my experimental setup. Most of the charge is on the plastic or glass jar.
+Andrew Kimble Maybe, but only if you were luck enough to find are transformer what was the right shape. You need to be able to move a tuning bar across the top of the coil to tune the crystal radio. You could instead carefully remove the wire from the transformer and wrap it around a toilet paper cardboard tube to make your own coil. Just be careful to not damage any of the thin enamel insulation that's coating the wire.
Here's my source en.wikipedia.org/wiki/Leyden_jar#Storage_of_the_charge which uses this source web.archive.org/web/20110727024546/www.sis.org.uk/bulletin/99/mills.pdf
@@RimstarOrg thanks for the source, but I feel its different than this unicorn charge particle theory. You can feel the electro static field, that's not based on particles but based in the electric field.
I taught for a software company (QNX) for 13 years, traveling around the world for them, and still teach other things on a part time basis (taught a solar cooking class yesterday!). But I've never taught science or electronics in classrooms.
They do discharge, but the charge on the plates when you pull the out is small, so it's not very noticeable. At 2:16, I point that out. You can see the plates losing chage starting at 1:55.
@@RimstarOrg I do understand the your explanation at 1:55 though but what I’m asking you is at 0:38 where the first plate and second plate touched each other. What puzzled me is that if I’m not mistaken both plates are conductors and they are charged (with equal amount of charge but opposite sign) so if they touch each other then both of them should be immediately discharge and both plates become neutral right? but it turn out at 0:59 after you reassemble the Leyden jar and you take the two alligator clips (one connect to the inner plate and another connect to the outer plate) close to each other and then there is a spark or discharge therefore that mean both plates are still charged even after you made both of them touch each other. So the question is how is there a spark at 0:59 even though both plate were already touched each other at 0:38? It would be cool if you help me further clear my confusion.
I guess I should have made another animation similiar to 1:55 but instead showing what happens when you put the plates back together. You're right, after discharging the plates at 0:38, they become neutral. But when you reassemble it, the electric field from the charge on the plastic recharges the plates, similar to how at 1:55 the electric field removed charge from the plates. That's why when you bring the alligator clips close together at 0:59, there's a spark.
+Andrew Kimble Parts list or pictures for what? Do you mean for the solar cell powering an amplifier to power a crystal radio? I that case just just build the amplifier in the video I linked to or using the details for it on this page rimstar.org/science_electronics_projects/make_crystal_radio_amplifier_for_speaker.htm but use a solar panel instead of a 9 volt battery.
I am sorry, but anyhow that whole explanation doesnt fit. Question. How can hold plastic an dipole, what parts of it can magnetize, to form a dipole. Where the next Question come. When plastic got dipoles, what kind of Material can it attract, since it becomes small magnets. Maybe only other small plastic parts what are "charged"? Maybe, but its more the electrostatic effect. Would that work with glass too? But then still, the charge is hold into the dielectric, not the plates, plates are then more the conductors. Anyhow the effect doesnt fit with explanation from the whole classic theorie.
The term, dipole, isn't only used for magnets. As you know, an atom container positively charged protons in the middle and negatively charged electrons surrounding it. If the negative electrons are off center then the whole atom is more positively charged in one direction and more negatively charged in the other direction. It becomes a dipole, two poles, one negative and one positive. The same applies for molecules.
RimstarOrg Ty anyway for your reply. A nice Video, simple and clear. Just, some Questions still left for me. Like one, how importend is the dielectric material at capacitors and its layout for the capacitance and the charge and discharge.
The dielectric is very important. The material itself, the thickness, surface area and breakdown voltage are all important. I go over them in quite a bit of detail in my two capacitor videos ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-GveI9gXIsHw.html and ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-MPD7skZ8OSo.html. The first one goes over how all that affects the capacitance and the second one talks about the breakdown voltage. I have another one, ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ml2TdQ2_2mk.html, that explains elecrtolytic capacitors, which are pretty neat since one of the plates, instead of being metal, is a very thin layer of aluminum oxide.
but that's nonsense! it's an insulator how could charge "jump onto it"? If charge could move across the surface of an insulator it would just move to the other side across the surface!
I didn't say charge moves across the surface of the insulator. You're right to say it doesn't. But charge can definitely jump onto or off of an insulator.
+Andrew Kimble I no longer know what you're asking. Or are you asking for something? It sounded like you were asking for a parts list or pictures, so I gave you a link to my webpage that has pictures, diagrams, videos,...
