Faraday cage (hollow conductors)

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A Faraday cage can still function effectively even with holes in its surface due to the relationship between hole size and the frequencies it blocks. While high frequencies can pass through these openings, the cage remains effective against low frequencies, which are blocked by the conductor. The effectiveness of the cage is influenced by the size and shape of the holes, as well as the spacing and amount of metal present. A general guideline suggests that the largest dimension of any opening should not exceed one-tenth of the wavelength of the highest frequency intended to be blocked. Understanding these principles clarifies how Faraday cages can maintain a zero electric field inside despite having perforations.
Pepealej
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Hi! I have a question regarding the Faraday cage.

I know how a Faraday cage works and understand the principles that make it work and why (potential difference, flux, gauss' theorem...) but I have a question.

Why some Faraday cages work eventhough they have holes in their surface. For example, I have seen things similar to wire fences used as faraday cages (in experiments with Tesla coils), and they work.

Why? Does this mean that the conductor can have holes in it's surface and still the electric field inside it is still zero?

Thanks! :)
 
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It's a question of the frequencies that you want to block. Holes allow high frequencies to pass through, but the shield acts effectively as a solid to low frequencies. The pass-band transition frequency is primarily determined by the size of the holes.
 
And which is the relationship between the size of the holes and the frequency?
 
The specifics are complex and depend on hole shape, spacing, amount of metal between holes, etc. As a very rough rule of thumb, largest dimension of any opening must not exceed lambda/10 of highest frequency.
 
I think he may be asking why it works, not how.
 

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