# How a Faraday Cage Works

## The Basic Concepts of a Faraday Cage are Illustrated Here

There are many ways to make a Faraday cage for a broad range of reasons. If you work with substantial amounts of electromotive and inductive electrical forces, some form of this is manditory. | Source
For those of us who need a blueprint, this illustration should give a basic idea of how to make a Faraday cage. Just remember to add the grounding circuit when done and it is in use. | Source

## The Faraday Cage and Like Ideas are in Common Use Today

A Faraday Cage is named after the discoverer of the principle, Michael Faraday, who described induction where electrical energy can be guided by a conductive substance like copper, aluminium or steel when excited by a magnetic force. To sum up his law on induction; The EMF (electromotive force) generated is proportional to the rate of change of the magnetic flux” (1). But the Faraday cage today is different from the concept of a simple conductor, because it can be used to isolate sensitive electronic components from a power surge that could come from an electromagnetic pulse or from a lightning strike. Why is this so?

The short answer is that electric force results when opposite charges attempt to balance out into a neutral state. Electric force can build up due to friction as in electrostatics or from induction by a magnetic force. Nature always seeks a levelling of forces, which is why we can step in and tap energy in transition. Electrostatic and electrical-inductive force comes in positive and negative aspects. When there is a surplus of one type or the other, the tendency is for dispersal. Electricians are familiar with the tendency of high voltage to disperse away from a conductor and thus can wear a conductive covering to allow the high voltage a path away from the body when working on high voltage circuits. The Faraday cage works in a similar manner by being an antenna and ground for high voltage or induction surge that comes from an electromagnetic pulse (EMP).

A typical Faraday cage is constructed so that it shields ether buildings from high voltage strikes, or the human body when working with high tension voltage or sensitive electronics from sudden EMP induction that can literally explode sensitive microelectronic circuits. They are essentially a hollow antenna that “picks up” over charges of electromotive or electrostatic force and dumps it into the ground, protecting anything that it surrounds.

## It's Easy to Build a Faraday Cage

The construction of a Faraday cage is simple in the extreme. They can be made of any electrically conductive material, can be made up of mesh wire or solid sheet metal. There are ready made answers in the form of galvanized metal garbage cans complete with lids. Some can be lined with insulating material such as cardboard for extra protection for anything inside. As same charge electromotive or electrostatic charge tends to repel, the force will naturally flow away and around what is being protected via the enclosing hollow Faraday cage. The Faraday cage can be grounded with something as simple as an attached heavy duty wire that is connected to a conductor driven into the ground.

Thus, when lightning strikes, or there is an EMP event, the sudden power surge is carried around what is being protected and directed into the ground to disperse, much as lightning does anyway in nature. The difference is that the Faraday cage will protect anything inside from a direct lightning strike, whereas the unprotected item will absorb the full impact of the instantaneous power surge and be destroyed in the process. That being said, let us look at some videos on how to be protected from high voltage and sudden inductive currents by the use of a Faraday cage.

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## More by this Author

chinese2learning 4 years ago from Beijing

Interesting! During dry seasons, I am scared of touching any metal.

syzygyastro 4 years ago from Vancouver, Canada Author

Cold dray weather is the worst. The air is dry and the temperature difference between an indoor heated space and sub zero outdoor temperatures is enough to really drive up the electrostatic potential. I've seen 1 to 2 inch sparks when I touch anything metallic on those days and it is quite a jolt.

Jim Lenahan 4 years ago

I have been searching for information on how to defend aginst the possible EMP and Solar Flare for months and finally a simple explanation for lay people. Thank you Jim

em_saenz 4 years ago from Europe

Thank you so much for answering my question and good luck in the contest.

dkmayo 4 years ago

I enjoed your Hub. The video really helped to show a real world application.