Dielectric constants what is the limit

[mishraanwesh]

Hi there,

Do we know which material has the highest dielectric constant (exact figures would be nice),and what is the highest break down voltage achievable for that particular material.

 

[vk6kro]

Wikipedia has some lists of these:

http://en.wikipedia.org/wiki/Dielectric_constant

http://en.wikipedia.org/wiki/Dielectric_strength

Note that this last one is in Megavolts per meter. Multiply by 10 to get Kilovolts per cm, or multiply by 25.4 to get Kilovolts per inch.

eg the dielectric strength of air is 30 KV per cm.

 

[f95toli]

The dielectric constant is temperature- and frequency dependent (in some materials there is a very strong dependence) which is why it is difficult to give exact values. High dielectric constants are also very difficult to measure with good accuracy.

A good example is strontium oxide (STO) which has a dielectric constant of about 300 or so at RTand MW freuquency, but that values goes up to to tens of thousands at cryogenic temperatures (unless you go up to about 1 THz or so when it drops down to about 10 or so)

 

[FizzyWizzy]

I once did a back-of-the-napkin calculation that, if we assume an electron is a dielectric-filled shell (mass) with a uniform surface charge (... total charge e ), the dielectric relative dielectric constant of the electron would be about 432. Probably not right.

I've changed my model a bit in the past year, but it's an interesting question to raise. What is an electron? No one knows. Anyone who says they do, is a liar.

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