Faraday cage Definition and 98 Threads

Imagine an uncharged solid spherical conductor. Inside this spherical conductor, there is a cavity of a weird shape carved out of it. And somewhere inside this cavity, there is a charge +q (or rather, a charge distribution of total charge +q). The charge +q induces an opposite charge -q on the...

Imagine an uncharged solid spherical conductor. Inside this spherical conductor, there is a cavity of a weird shape carved out of it. And somewhere inside this cavity, there is a charge +q. The charge +q induces an opposite charge -q on the wall of the cavity of the conductor, which distributes...

So I made this Faraday Cage to block wifi in all directions but 1, to block it from my neighbor. Each side has 6 Layers of aluminum foil on it with no gaps, It looks sloppy because when I tried it and it didn't work I quickly added more trying to make it work. If I put my router inside this...

I am building a walk in size faraday cage. In order to make it re-positionable, I am creating 6 wooden frames (top, bottom and sides) covered in 2 or 3 layers of aluminum screen from a hardware store. I am using at least 2 layers of screen, because that is how many layers it takes to cause my...

I hit a 1:40 ratio pulse transformer with a 1000V (100mA) sawtooth pulse and it creates a spark gap. Unfortunately it also creates a lot of EMI and my micro-controller and power supply has problems because of it. How do I stop this? How do I know what the wavelength is of the EMI field so I...

Okay- first off, I know enough science to sound like an idiot, so please be gentle :-) Now, IF you had a dragon that generated an electrical charge, it wouldn't be able to direct it, lightning-style, without being able to generate an opposite charge at it's target- right? So in essence, to shot...

if I build a faraday cage just to protect device from lightning or other electrostatic source (not electromagnetic pulse), and I need that as light as possible... I will build it using a mesh to make it light.. now, how large the mesh' holes is allowed ? is there any calculation for this...

Hi guys, The other day I found myself asking the question below and couldn't quite manage to re-align my own personal experience with E&M theory. I am sure it will just be a gap in my knowledge base of E&M. The Question: If you are contained within a metal mesh cage which acts as a...

Hi ,imagine a situation , we have a large tesla coil, a faraday cage , a man in it and he cage is grounded. Now we switch on the coil high frequency high voltage currents makes a breakdown of air and produces a path so that the current goes and strikes the cage.Now according to faradays law the...

Is there a force in this case: For the sake of simplicity, a spherical Faraday cage. A smaller charged sphere inside. If we move the small sphere close to the wall of the cage, will there be a force of attraction between the wall of the cage and the small charged sphere?

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...

HI Assume we have a point charge in the center of a shell, now the inside inner wall will get an opposite charge and the outer side of the shell will have the same charge as the point charge. Since we have a charge on the out side, how isn't there any fields outside ?? how are we...

I was wondering how protective a Faraday Cage actually is, can it be overcome by sending more amperage onto the exterior or does that not matter? Also what would cause a Faraday cage to be ineffective, like would a cord powering the device inside render the cage useless? Thanks for your help!

Hi, I am a biologist and I do a lot of experiments on cellular electrophysiology. I keep my preamplifier and the biological subject inside a Faraday cage, and it works well. In some experiments I need to deliver a drug to the cell so I have to enter the cage briefly, with my hand only, and...

So I tried out a small, fun experiment of putting my cell phone in the microwave (not turning it on, of course) to see if the WIFI Hotspot capabilities were hindered by the Faraday cage that insulates the microwaves. I had heard that microwave cages will hinder If not completely block 802.11...

Hi, A parallel plate capacitor is charged from fixed voltage, after I cut voltage source. Now, what's happened if I place a Faraday cage inside capacitor (without touch capacitor) ? Capacity changed ? So energy of capacitor changed ?

I was looking for a mathematical explanation of a Faraday cage. In particular I was seeking something that relates hole size to the reflected and transmitted waves, using electromagnetic theory. This might also relate to a wire grid polarizer. Would anyone be able to help me?

Hello learned Engineers, Physicists, and people more useful than myself: Thank you in advance for reading. I would like to submit a more educated proposal to a utility company for a method that would allow it to install 500 kilovolt renewable power transmission lines through many residential...

The most difficult aspect of hydrogen fusion is overcoming the electrostatic forces that cause the hydrogen nuclei to repel each other. Would it be possible to place one of the nuclei inside some conducting sphere like a Buckminsterfullerene so that the fullerene acts as a Faraday cage? The...

[b]1.I must make a Faraday cage with copper mesh that will protect product from stray 400 MHZ signals.The operator wants to see his product inside of the cage so i want to use the coarsest mesh I can for visibility reasons.I still need good protection from 400mhz.What is the coarsest copper mesh...

Hoi! I was wondering about the Faraday cage. When lightning strikes a car, the driver is not hurt since he/she is sitting in a Faraday cage. The charges cancel out and the net E field in the car is zero, though the potential inside the car should reach whatever is on the outside, meaning...

Hi everyone, I have recently built a Faraday Cage. However it seems to be working in reverse and amplifying the noise! My test setup: I place a 3.3 Mohm Bulk metal precision resistor across the terminals of the meter and measure the pk-to-pk noise using the meter. I now place the meter...

Can a faraday cage be used to stop the radiation at the Japanese reactor? If not why not? I know the frequencty is high but what if you pulsed DC current at the same frequency would that stop it?

Hello I am building a Faraday cage, I cannot find any decent information on the designing one. I plan to use it to shield a precision resistor network and 8 1/2 digit DVM in order to measure Low Frequency noise of a HV power supply. I need to know what dictates the size of the "holes" in...

Would a faraday cage block all types of radar?

I'm working on a project that has a 13.56 MHz RF power source. The thing is, the EM waves emitted by this power source cause problems with the diagnostic equipment of the actual experiment (various capacitive and inductive sensors). So, I am planning to build a faraday cage to shield the...

Most places I've read say it's because the car forms a Faraday cage, but a few say that is incorrect and that it's actually from the skin effect. The notable case of the latter explanation is from the Boston Museum of Science: http://www.mos.org/sln/toe/cage.html This guy, Dr. Davis from the...

I'm working in a tracking solution based on RFiD, that consists on tags without any type of battery or power source. When the antenna generates the signal in the correct frequency, an induction process occur in the tag, generating a response to the antenna (containing the tag's id number)...

When this guy gets inside the Faraday cage and they hit it with like 200,000 volts from a Tesla coil , when he is inside the cage he can touch the inside and not get shocked , so basically the charge flows on the outside , is this because the electric field from all around the circle pushes...

Hi everyone! I was thinking..then I decided to post this thought to ask your opinion about that. We have this capacitor made by different layers, starting from the top we have: electrode, dielectric material (let's assume 10um thick, permittivity k=600), conductive layer (good liquid...

I have designed an electron gun that incorporates a faraday cage setup and I would like anyone's opinion if this setup could actually work. See attachment for image or here is a link to the image of the electron gun http://yfrog.com/j7electrongundesignbj Explanation of image There is a...

Hi everybody. Some expert advice needed here. I am working into an experiment that consists of putting a wave emitter device (a wi-fi router for example) in a faraday cage so those waves don't spread outside the cage (or I get some attenuation at least). I have some questions: - First of...

Well we can use a Faraday Cage to keep magnetic fields from entering a certain area, but I was wondering if the same method could work for containing magnetic fields. I know we use metal cores to concentrate magnetic fields, but is there a way to actually trap them?

1. Suffer extreme symptoms from Microwave RF emissions cell phones, Wi FI, Cordless computers and RF Routers. 2. The next door neighbour has installed a Uniden DECT that transmits continually 24 hours a day. Our bedroom and the next door neighbours loungeroom is separated by a normal...

A real life situation exists where I'm attempting to turn the back of a van into a faraday/rf sheilded cage to transport 2 electromagnetic sensitive beings too properties where there is no microwave tower coverage in the hope they can live fuller longer lives (than are currently expected) in a...

Couple of months ago Deany100 posted a note on microwave radiation which he suspected was his neighbour tracking his movements. I've got a similar problem, a home bathed in emf picked up by a device (15 pounds sterling) that doesn't tell me what the frequency is. Great disbelief from everyone...

I have a few questions and verifying statements regarding the concept as well as practical building of Faraday Cages. 1. A Faraday cage's mesh must have a grid with a spacing less than that of the wavelength that is intended to be stopped. 2. Why is it that foil and mylar also work as...

Homework Statement For my physics project I decided to make a Faraday cage to cancel out cell phone signal. Homework Equations The Attempt at a Solution For my first attempts at making a successful project I used chicken wire and wire mesh to make a cylindrical cage. Our goal was...

Dear readers! I wanted to arrange a little demonstration for my relatives with my cellphone inside a Faraday cage. Of course I expected no EM waves to be present inside the cage, which means that my cellphone wouldn't ring when being called. Well, we repeated the experiment several times...

I have a question regarding Faraday Cages... Faraday Cages blocks static electrical fields I read somewhere that static magnetic fields can penetrate the faraday cage when changed slowly. Faster changes in static magnetic fields cannot penetrate a faraday cage, is this true? Also does...

Hi! I want to know what will happen if I insert current (moving electrons) into Faraday cage, which is ungrounded? Will still there be no electric field, inside the cage?

[SOLVED] Faraday cage problem A man is standing on a rubber mat which is isolated. You place a Faraday Cage around the mat. (the cage is standing on top of the mat) The man is touching the cage Now when lightning hits will: 1) the cage be loaded with electricity 2) the cage not be loaded...

Hello all, I plans to reduce RF strength in my apartment by cover the room with conductive material. - Cover 2 walls which facing the boardcasting tower. - Cover the floor and ceiling. Total 4 sides (since the material is quite expensive) Then I'll grounded them to the apartment...

i heard that a faraday cage is often used in shielding e.g. sensitive electrical equipment. I was just wondering, because, in http://socrates.berkeley.edu/~fajans/Teaching/cartoons/Shielding/TestChargeShielding_files/frame.htm it seems that the electric field is not zero at ALL times. i.e...

I've looked this up extensively on the web but nothing seems to answer this question satisfactorily. For example, here's Wikipedia's answer. I try thinking of it considering the properties of a conductor in electrostatic equilibrium. The charge on a conductor in equilibrium resides on the...

http://img212.imageshack.us/img212/2931/energyplan26qs.th.png There is my uh rudamentary drawing of a scenerio where something emitting em waves(green) is surrounded by a faraday cage(yellow). umm I believe current is induced in the 'cage', how would I divert the current to use, because if I...

Hi, We know that in a space region free from electric charges and surrounded by a conducting surface, the electric field must be zero (this is the Faraday cage). I suspect that this statement can be derived directly from the Maxwell equations, but I don't find this derivation anywhere...

please forgive a not very scientific question, i am wondered if static electricity can penetrate a faraday cage, this has to do with ball lightning being seen in an aircraft.