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Samson4
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If I crumple and unfold a piece of foil, am I increasing it's surface area? Since it's malleable, if I step on it with golf spikes, without completely piercing it, will it gain surface area?
Samson4 said:Well I mean the conductors, not the dielectrics. Film capacitors are metalized so that might be hard to do. But ceramics have solid electrodes I believe. Why don't they increase their surface area?
Wow! that's great ! and i think its really fun doing that indeed.Samson4 said:To increase the capacitance of my homemade caps. A lot of the things I'm doing needs very specific specs that I don't find available. Also, I enjoy making them.
Bystander said:You're looking at the volume of the dielectric, its surface area times thickness, not a fractal surface area of the plates when calculating capacitance.
Joseph Austin said:un doing that indeed.
I suggest use foil as an alternative capacitance for your homemade c
It is not manipulable in the sense you want. If the dielectric spacing is small compared to the scale of the surface irregularities, and you can "nest" your enhanced surface area plates like cupcake pans, it's worth the effort. Scaling each layer differently to roll sheets of cupcake pans isn't worth the engineering and fabrication headaches.Samson4 said:Is it no manipulable?
Electrolytics aren't really capacitors --- they're batteries with low capacities and high discharge rates, and electrode surface area does make a difference.Samson4 said:Why do they etch the aluminium in electrolytic capacitors?
If you just make the surface of the electrodes 'rough' you may be increasing the area but you are also increasing the spacing between some parts of them and that must decrease the overall capacitance, I think. If you make 'spikes' then you would need to produce matching spikes in dielectric and the other plate, which would be difficult - especially at home because of the possible tolerances. The clever thing about good conventional capacitor design is to make the spacing and dielectric thickness as uniform as possible because it is the point of least separation that determines the maximum operating voltage.Samson4 said:Im more interested in very small imperfections. For example, if I etch my foil with hcl, will this increase the capacitance?
sophiecentaur said:If you just make the surface of the electrodes 'rough' you may be increasing the area but you are also increasing the spacing between some parts of them and that must decrease the overall capacitance, I think. If you make 'spikes' then you would need to produce matching spikes in dielectric and the other plate, which would be difficult - especially at home because of the possible tolerances. The clever thing about good conventional capacitor design is to make the spacing and dielectric thickness as uniform as possible because it is the point of least separation that determines the maximum operating voltage.
If you want to make good home made (tubular) Capacitors then you need very flat foil with no burrs on the cut edges and a very uniform thickness dielectric. Also, you have to wind them (Swiss Roll construction) uniformly tightly and exclude any dust or dirt. I have given students the task of producing Capacitors for a homework task and they mostly are just not careful enough to get good results - internal shorts are very common. If you are very careful, though, you should be able to achieve something worth while. Good luck.
The surface area of foil refers to the total area of the foil's outer surface, including all sides and edges.
The surface area of foil can be calculated by multiplying the length, width, and height of the foil together. If the foil is irregularly shaped, it can be divided into smaller regular shapes and their surface areas can be added together.
Yes, the surface area of foil can be increased by folding or crumpling it. This increases the number of folds and creases, creating more surface area.
Increasing the surface area of foil can be useful for various purposes, such as increasing its strength or creating more surface for heat transfer. It can also be helpful in packaging, as it allows for more efficient use of space.
Technically, there is no limit to how much the surface area of foil can be increased. However, at some point, the foil may become too thin or fragile to serve its intended purpose, so it is important to consider the functionality of the foil as well.