How Do Faraday Cages Work

Electricity has numerous uses in our society. From computers to dishwashers, electricity is useful in any number of ways but too much of it can be harmful for obvious reasons. This is where a Faraday cage comes into play. Faraday cages are used to protect sensitive electronics from dangerous electric fields that can damage them and leave them completely useless.

Faraday cages often look like, well, a cage. They are built out of a conductive metal mesh that surrounds the sensitive electronics. This mesh of metal absorbs electromagnetic radiation that can be found throughout the universe and distributes it around the cage instead of letting it damage the components inside of it. This isn’t the level of radiation that can be harmful to humans and it’s not essentially harmful to electronics. Electromagnetic radiation is what allows for radio signals, microwaves, and even Wi-Fi but some types can be harmful.

When a charge or radiation comes into contact with a Faraday cage, the charge is distributed around the exterior of the cage by flowing through the conductive mesh. When this happens the charge inside of the cage is canceled out and the components that are inside are unaffected by the charge.

The Faraday cage was invented by Michael Faraday during his experimentation in the 1800s when he noticed that when conductors are charged, they only exhibited the charge on their surface. Faraday further tested his findings by lining a room with aluminum foil, placing an electroscope, a device that measures charge, into the center and charging the aluminum foil. The electroscope showed that there was no change in the charge in the center of the room. Although this particular instance didn’t yield much practical use, the concept went on to be developed by other scientist and inventors to become some of the most import inventions of the age.

In the modern world, most of our vehicles, like planes and cars, are made using metal which will absorb the electricity and make it pass around the occupant rather than through them, making travel much safer. Microwaves reverse the common effects of Faraday cages by trapping waves inside them rather than keeping them out to cook food quickly. Metal faraday cage suits can be worn by technicians when they are working with high voltage electrical lines. Faraday cages are often used by electronics companies, military outposts, and the government to protect sensitive and vital electronic and communication equipment from EMP (electro-magnetic pulse) attacks.

EMP attacks are some of the greatest threats to modern society that relies hugely on electronics and computers for everything. In the 1800s, the sun sent out a short but powerful burst of electromagnetic waves. As this was early into the use of electronics there wasn’t much to be damaged but the unprotected telegraph stations and power lines exploded or caught fire. This can be replicated on a smaller scale by EMP devices that could short out and destroy electronics with ease. Faraday cages are some of the only protections against EMPs which is why they are in broad use today.