Faraday cage - How a Faraday cage works

A Faraday cage is an enclosure designed to exclude electromagnetic fields. It is an application of Gauss's law, one of Maxwell's equations. Gauss's law describes the distribution of electrical charge on a conducting form, such as a sphere, a plane, a torus, etc. Intuitively, since like charges repel each other, charge will "migrate" to the surface of the conducting form, as described below. The application is named after physicist Michael Faraday, who built the first Faraday cage in 1836, to demonstrate his finding (see below). ...

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• Faraday cage - Faraday's finding
• Faraday cage - The idealized Faraday cage
• Faraday cage - How a Faraday cage works
• Faraday cage - Real-world Faraday cages

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Faraday stated that the charge on a charged conductor resided only on its exterior, and had no influence on anything enclosed within it. To demonstrate this fact he built a room coated with metal foil, and allowed high-voltage discharges from an electrostatic generator to strike the outside of the room. He used an electroscope to show that there was no electric charge present on the inside of the room's walls. This shielding effect is used to eliminate electric fields within a volume, for example to protect electronic equipment from lightning ...

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Faraday cage, Faraday cage - Faraday's finding, Faraday cage - The idealized Faraday cage, Faraday cage - How a Faraday cage works, Faraday cage - Real-world Faraday cages

Read more here: » Faraday cage: Encyclopedia II - Faraday cage - Faraday's finding

Faraday cages are often put to a dual purpose: to block electric fields, as explained above, and to block electromagnetic radiation. The latter application is known as RF shielding. Practical Faraday cages can be made of a conducting mesh instead of a solid conductor. However, this reduces the cage's effectiveness as an RF shield. Some real-world structures, such as automobiles, behave approximately like a Faraday cage. That's why: If lightning hits near a car, it does not affect the people sitting in the car. If artificial lightning is produced inside a mesh of ...

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Faraday cage, Faraday cage - Faraday's finding, Faraday cage - The idealized Faraday cage, Faraday cage - How a Faraday cage works, Faraday cage - Real-world Faraday cages

Read more here: » Faraday cage: Encyclopedia II - Faraday cage - Real-world Faraday cages

Consider an idealized hollow electrical conductor such as an empty sphere or box. If the outside of the cage is an idealized conductor, it will form an equipotential surface, that is to say, its surface will have the same electrical potential at every point. If there is no electrical charge inside the box, then by Gauss' law and the divergence theorem, there should be no electrostatic field inside the equipotential surface, regardless of what the field is outside the box. Since the electrostatic field equations are linear, even field-generating charges in ...

See also:

Faraday cage, Faraday cage - Faraday's finding, Faraday cage - The idealized Faraday cage, Faraday cage - How a Faraday cage works, Faraday cage - Real-world Faraday cages

Read more here: » Faraday cage: Encyclopedia II - Faraday cage - The idealized Faraday cage