Faraday cage Definition and 98 Threads

Some companies seem to be selling "smart glass" products that can be electrically tuned at will to be either mirroring or transparent, at least in visible wavelengths. Suppose someone were to Faraday shield a room to prevent van Eck phreaking or whatever kind of eavesdropping from outside...

Is this a good response? The lift is a conductor, therefore electrons can move freely. The charges on a conductor reside on the outer surface as they like to be as far from each other as they possibly can be due to the repulsive coulomb force. There is no charge between the inner and the outer...

We have built a faraday cage out of 1,5mm thick galvanized steel sheets. Size is 1.5m*1.25m*1.5m. The steel got powder coated and was assembled on a frame. Each side of the cage is made from separate sheets that are joined using rivets. All of the separate sheets are connected with grounding...

Are A and ϕ always zero inside a Faraday cage, like E and B are? If not, can its design be modified to accomplish that? If not, is there an analogous mechanism that'd always have A=0 and ϕ=0 inside?

A faraday cage made of a perfect conductor would theoretically have a zero E field inside. However, are there cases where a faraday cage made of a real conductor like copper wouldn't block out all EM radiation, like very high or low frequencies? How can the design be improved to make a real...

Hi All, I’d like you to weigh in on a debate I’ve been having. I’ve been thinking about a Faraday Cage (FC from now on) but from the opposite perspective. Sure it stops EMF getting in. But does that also mean, if there are items emitting EMF in there, that gets trapped within the room. Taking...

How did you find PF?: Via Google search From what I understand in scientific publications, if there is a strong solar storm directed towards the Earth, the effects would be such that any electronic equipment would suffer irreparable damage. I ask, if I put my computer inside a Faraday cage...

Hi. I was reading about conductors in electrostatic equilibrium and how it makes sense that they have zero electric field inside the material even when an external charge is brought near. The charge density of the material just rearranges itself to cancel. Then I searched for hollow conductors...

I came across a problem that seemed fairly interesting; it asks what would be the trajectory of an electron released from rest inside a Faraday cage (which is itself within a uniform gravitational field ##\vec{g} = -g\hat{y}##). I didn't quite understand their explanation. They say that...

I've been reading about faraday cages. The way I see, it works because the condutor will separate the charges so that the eletric charge inside is 0. Then I saw a lecture in which the professor was carrying a radio and the signal stopped as soon as he entered the cage however we were still able...

It is possible to show via Gauss' law that the the net flux through a surface within the Faraday cage must be zero, however this is not a sufficient condition for the electric field to be zero. For the electric field to be zero in the interior of the cage, all points within the cage must be at...

Is there a need to put a household router in a faraday cage to cut down on radiated signals that could damage the human body? I would think the manufacturer's would have shielded what needs to be shielded. I see these advertised on Amazon among other places. My router sits about 6 feet from...

So I'm trying to put together a Pi Zero mini computer to use for security-oriented applications, for example encrypting/decrypting messages, working with encryption keys, etc. It's cheap, very small and thus easy to carry around. However, I'm not entirely comfortable with the presence of the...

I'm working on a wifi device testing box and made the first prototype of the Faraday cage. I need holes because of cooling. For this reason, the box has 3mm diameter holes on the top. The box made from steel, and have 2mm wall thickness. The wavelength around 12,5 cm for 2,4 GHz and 6 cm for...

Why does a Faraday Cage work? (or more generally, why does the inside of a conducting shell have no electric field if there are charges placed outside it?) I understand that this is the result of polarisation, but why does the polarisation happen to exactly cancel out the field? Could there be...

Greetings, I have a question regarding the attenuation properties of Faraday cages. More specifically, I'm looking for a generalization I can use to better understand how thick they should be for a given frequency. I did a small experiment by taking a small enclosed aluminum box and placed an...

Does chromium oxide reduce the effectiveness of a faraday cage constructed from stainless steel mesh? I am using mesh that is like insect screen for windows. It will be in moist environment. I appreciate your help!

In the Faraday cage, after injecting the charge, it takes about a nano second for charge to be distributed over the external surface. Why doesn't one become electrocuted in this very little time (nano second)?

Dear forumers, I need a 50hz 250VAC power line filter for an EMI shielding faraday cage. The filter should work between 100khz and 20ghz, attenuation should be >=60dB between 1mhz - 5ghz. Regular power line EMI filters like this don't seem to go that high (only up to a few hundreds of mhz...

Hi guys, I'm wanting to simulate faraday cage form, analysing mesh perforations defined by wavelengths of different electromagnetic spectra (eg. radio, microwave, UV etc). Are there any good analysis softwares which I could import a pre-made digital model with these perforations and simulate...

Hi guys, I'm wanting to test materials developed in CAD software for their radiation blocking qualities (EM Spectrum), I would ideally need to use a software where I can set the wavelength and frequency of the emitter and set up a receiver, allowing me to place different materials in the middle...

I'm trying to understand if it does exist something (material, construction) that shiled you against alll kind of electromagnetic radiations. Something that shields you from the lowest frequency radio waves up to the highest frequency gamma rays. I've read about faraday cage but it does not...

If inside of a metal (for ex. Aluminum) enclosure, could it potentially create more harm than good if frequencies were able to penetrate due to an imperfectly sealed cage or due to a relatively high power level of frequencies that allowed them to penetrate the metal? If the power level was high...

I have a function of the cartesian coordinates x, y, z such that: f = a * ln|sin(px + iqy)| + by + c This equation should be describing the electric field nearby the wall of the Faraday cage. I solved the Laplace equation Δf = 0 and got : p = +/- q, so p = q. I should choose the constants...

In the following video: I understand how the Faraday Cage works, but what has me confused is the arching. If charge is building up on the sphere and then arching over to the cage, where then is that charge sunk to? You would think it would stop arching when there was sufficient charge on the...

So i have learned about the ability of Faraday Cage for blocking an external electric field. But is the thickness of the conductor effect the ability? Is there any limit of its thickness so that the cage won't be able to block external electric field anymore? I have read and searched about this...

A metal piece has no E field inside too. Why must the microwave use a metal mesh with hollow spaces to block radiation? They can simply use a metal piece just like the interior part of the box.

Hi. Is it possible to derive the properties of a Faraday cage from Gauss' law alone? I found some "derivations" which I find rather unconvincing since they somehow conclude from a vanishing flux that the E field must vanish as well. Some slightly more elaborate derivations use a combination of...

Hi. Assume a long hollow wire that both carries a nonzero net charge and a current. Is it still true that all charge sits on the outer surface of the cable and that the empty space inside is field-free (Faraday cage)? I know proofs of those facts in electrostatics using Gauss' theorem, but they...

This is an interesting short article from SIAM news that says the Feynman lectures are wrong about the Faraday cage: https://sinews.siam.org/DetailsPage/TabId/900/ArtMID/2243/ArticleID/757/Surprises-of-the-Faraday-Cage.aspx

Faraday cages of the conducting type are not effective for lower frequencies; https://en.wikipedia.org/wiki/Electromagnetic_shielding#Magnetic_shielding mentions a frequency of 100 kHz. The electromagnetic spectrum is composed of both an electrical, and a perpendicular magnetic field. If a...

Hi, I was wondering if I could make my house a big Faraday cage capable of blocking Wifi and cellphone signals from the outside by covering all of the inside walls with chicken wire? How big of a problem is it that windows would stay uncovered? Or that electrical wiring inside the wall (so...

Hi pf, Please could someone provide an explanation of why the relationship between the wavelength and size of the gap is the significant factor for determining whether or not it blocks radiation in particular reference to the mesh on the door of a microwave oven. It seems very simple when a...

If I use 10mm (thickness) of a metal for the sides of a Faraday cage, with a 5mm skin depth at the frequency to be shielded, & increase the v/m of the EM wave to be blocked gradually, will there be a stage where the skin depth will increase to 6mm, or is 5mm the maximum limit?

Another question and a another terrible illustration. So my question: do faraday cages interfere with dispersion of ionic solutions? In the illustration, a chemical reaction or some other cause for a lower concentration of ions is happening inside a faraday cage at B. Will the solution disperse...

In our school we made a submarine. The inner hull is a few cm thick metal, so it should be a good farady cage, but it does not act like one when blocking wifi from inside the hull. Wifi antenna is not touching the hull. The hull acts like a faraday cage when blocking a phone signal from the...

Homework Statement I am having trouble understanding how a Faraday cage works.Homework Equations $$\oint \vec{E}\cdot\,d\vec{A} = \dfrac{Q_{encl}}{\epsilon_{0}}$$ The Attempt at a Solution It says that Faraday cage is a hollow metallic conductor and hence, inside the cage, $$\vec{E} = 0$$ I am...

Here is what it looks like I have two questions. 1) What if the guy sticks a finger out of the cage? 2) The idea is that it doesn't matter if the cage is solid or hollow (has bars). As long as it's a conductor, the man inside is safe. What if I start removing the bars to make the cage...

Can a cylinder with 1 side open act as a faredey cage (which do not allow passage of magnetic field) when magnetic field are only coming parallel to the curved part

Hello. I was trying to understand the mathematics underlying Faraday cages. After hours of research on the web, It turns out that there are very few mathematical analysis related to Faraday cages, even in the electrostatic case, and those that I read do not satisfy me. So, I tried to solve the...

"A Faraday cage or Faraday shield is an enclosure formed by conductive material or by a mesh of such material. Such an enclosure blocks external static and non-static electric fields by channeling electricity along and around, but not through, the mesh, providing constant voltage on all sides of...

Hello. Let's say we build the Faraday cage which surround strong radiation such that no radiation can escape to outside world for safety. What happens on external surface of the Faraday cage in voltage during shielding? Is it fluctuated?

Hello. The ground plane is sometimes used as current return path. If current is low frequency and amplitude is small then voltage rising due to current flow can be ignorable. However, what is return current is actually very high in both frequency and amplitude? In our lab, gas discharge...

Hi, I am making a faraday cage to be used in reactive ion etching of silicon. I was wondering if the size of the cage, or the surface area has any impact on it's effectiveness or how it works? I know the size of the mesh and the material I use, as well as whether or not it is grounded all...

Hi there, I recently attended a physics demonstration (Lightning show at Boston Museum of Science, my favorite exhibit obviously), where the educator argued that the reason she could safely sit in a Faraday Cage while lightning was striking said cage was the skin effect. As I understand it...

Hello. I've recently have a lot of question of building Faraday cage for our high voltage gas discharge lab. I think this question is a kind of fundamental question for such a job. Let's say I would make perfect Faraday cage with perfect shielding or have metal plate of infinity transverse...

Hello. I've uploaded similar question before but I think it is time to make this clear. I've seen the attached one during reading of grounding. In the picture, the body of the power line filter (or ground of the filter) is connected to inner surface of Faraday cage and signal ground is...

Imagine there is a hollow toroidal conducting chamber and a long solenoid in the middle. When we power the coil, does the induced electric field "propagate" inside the chamber? My prediction is that the changing flux will cause induction regardless of the cage. Thank you.

A recent thread talked about a radio inside a metal box. That reminds me of a question I never resolved. 9 years ago my sailboat was struck by lightning. 6 people were on board, but nobody was hurt, luckily. My mast is grounded to an underwater plate via a thick copper cable inside a plastic...

Hello. Let's say there is a instrument needed to be EM wave-shielded in High voltage discharge lab. Building Faraday cage becomes necessary and the instrument is moved to inside the cage. The cage is grounded to lab ground and the frame ground of the instrument (it is also signal ground for the...