Attention Deficit Disorder Prosthetic Memory Program

Faraday Cage

ADDPMP134

A Faraday cage or Faraday shield is an enclosure used to block electromagnetic fields. A Faraday shield may be formed by a continuous covering of conductive material, or in the case of a Faraday cage, by a mesh of such materials. Faraday cages are named after scientist Michael Faraday, who invented them in 1836.

A Faraday cage operates because an external electrical field causes the electric charges within the cage’s conducting material to be distributed so that they cancel the field’s effect in the cage’s interior. This phenomenon is used to protect sensitive electronic equipment (for example RF receivers) from external radio frequency interference (RFI) often during testing or alignment of the device. Faraday cages are also used to enclose devices that produce RFI, such as radio transmitters, to prevent their radio waves from interfering with nearby sensitive equipment. They are also used to protect people and equipment against actual electric currents such as lightning strikes and electrostatic discharges, since the enclosing cage conducts current around the outside of the enclosed space and none passes through the interior.

Faraday cages cannot block stable or slowly varying magnetic fields, such as the Earth’s magnetic field (a compass will still work inside). To a large degree, though, they shield the interior from external electromagnetic radiation if the conductor is thick enough and any holes are significantly smaller than the wavelength of the radiation. For example, certain computer forensic test procedures of electronic systems that require an environment free of electromagnetic interference can be carried out within a screened room. These rooms are spaces that are completely enclosed by one or more layers of a fine metal mesh or perforated sheet metal. The metal layers are grounded to dissipate any electric currents generated from external or internal electromagnetic fields, and thus they block a large amount of the electromagnetic interference. See also electromagnetic shielding. They provide less attenuation of outgoing transmissions than incoming: they can block EMP waves from natural phenomena very effectively, but a tracking device, especially in upper frequencies, may be able to penetrate from within the cage (e.g., some cell phones operate at various radio frequencies so while one cell phone may not work, another one will).

The reception or transmission of radio waves, a form of electromagnetic radiation, to or from an antenna within a Faraday cage is heavily attenuated or blocked by the cage; however, a Faraday cage has varied attenuation depending on wave form, frequency or distance from receiver/transmitter, and receiver/transmitter power. Near-field high-powered frequency transmissions like HF RFID are more likely to penetrate. Solid cages generally attenuate fields over a broader range of frequencies than mesh cages.

Faraday Cage - © Attention Deficit Disorder Prosthetic Memory Program
Sinkhole - © Attention Deficit Disorder Prosthetic Memory Program
ADDPMP191
Sinkhole
Miamira Magnifica - © Attention Deficit Disorder Prosthetic Memory Program
ADDPMP311
Miamira Magnifica
Mundaneum - © Attention Deficit Disorder Prosthetic Memory Program
ADDPMP071
Mundaneum
Nasa Aerogel - © Attention Deficit Disorder Prosthetic Memory Program
ADDPMP151
Nasa Aerogel
GAINSBOURG BURNING 500 FRANCS - © Attention Deficit Disorder Prosthetic Memory Program
ADDPMP116
GAINSBOURG BURNING 500 FRANCS
Savonius Wind Turbine - © Attention Deficit Disorder Prosthetic Memory Program
ADDPMP382
Savonius Wind Turbine
Low Orbital Spider Webs - © Attention Deficit Disorder Prosthetic Memory Program
ADDPMP111
Low Orbital Spider Webs
Abu Dhabi by Jack Burlot - © Attention Deficit Disorder Prosthetic Memory Program
ADDPMP230
Abu Dhabi by Jack Burlot
The Philip Experiment - © Attention Deficit Disorder Prosthetic Memory Program
ADDPMP407
The Philip Experiment
Luther Blissett Collective - © Attention Deficit Disorder Prosthetic Memory Program
ADDPMP015
Luther Blissett Collective
Optical Camouflage - © Attention Deficit Disorder Prosthetic Memory Program
ADDPMP105
Optical Camouflage
Five-Hundred-Meter Aperture Spherical Telescope - © Attention Deficit Disorder Prosthetic Memory Program
ADDPMP434
Five-Hundred-Meter Aperture Spherical Telescope

You are using an outdated browser.
Please upgrade your browser to improve your experience.