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Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
we all know there is a load if research going into super conductors, but are there any super insulators available to us mere mortals out there?
They would make building the ultimate Tesla coil easier if there were! No more flashover at 1 million volts!
Interestingly I did some research into breakdown awhile ago and found out that it's a lot more complicated than that!
Given a homogeneous field (like that between balls who's spacing is greater than their diameter) the breakdown voltage is far higher, it's about 30kV/cm.
The breakdown voltage actually increases with humidity until you get condensation (fog), what does decrease is the tracking distance (how a discharge will tend to travel along the outside of an insulator).
The breakdown voltage vs distance relationship isn't linear; it's smaller for larger gaps than smaller gaps.
The breakdown volltage for a given gap decreases with pressure upto a certain point then increases sharply - a vacuum is the best insulator.
Donesn't the resistance of non metals like graphite increase as temperature decreases?
I have a feeling that all non-metals are super insulators at superconducting temperatures. This would make sense, at low temperatures no power can be dissipated something either conducts electricity or it doesn't.
As I recall, both graphite and carbon have positive temperature coefficients with regard to their resistance.
Air, vacuum and most other gasses are similar in insulating properties. Of course, neon, helium, argon, xenon and krypton are another matter entirely! It takes a solid insulator properly designed to handle the high voltages. Sometimes there may be a trade-off between voltage breakdown capability and dielectric constant, although the two sort of tend to go hand-in-hand.
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