Faraday cage, what is it? What is its application

Today we are going to talk about the famous Faraday Cage! So if you still didn’t know it or have doubts about its application, I invite you to continue with us in this article and stay on top of how it came about and how it can save your life, come on guys!

What is Faraday Cage?

The Faraday Cage emerged in 1930, from an experiment carried out by the English physicist Michael Faraday. This cage is a way to prevent the entrance of electric and magnetic fields inside conductive surfaces and structures. A curiosity is that the Faraday capacitance unit , was named after Michael Faraday

Faraday discovered that the electric field when applied to a surface or structure with conductive ends, causes the surface to produce electric charges opposite to the electric field, that is, these opposite charges cancel the external electric field creating a barrier that prevents the entrance of the electric field. inside the surface, as you can see in the image below.

Understand how the electric field surrounding the Faraday Cage works

This barrier shown in the previous image is also called electrostatic shielding and to prove his studies, Faraday built a metal cage charged electrically by a high voltage generator and entered it to prove it was safe to stay inside! Hence the name “Faraday cage”.

What is the application of the Faraday Cage?

Therefore, the Faraday Cage is a protective barrier against unwanted electrical and magnetic fields. It has a huge practical application and one of the biggest examples found in our daily lives is the microwave device, it has an internal coating suitable to contain electromagnetic waves only inside. Another good example is cars that can also function as a Faraday Cage.

The Faraday Cage allows you to create an insulation barrier in electrical and electronic devices so that the electric or magnetic field generated inside a device does not cause interference with other devices close to it.

A good example of this are the power supplies as shown in the image below, they are able to prevent the output of signals and also prevent other signals from interfering with their internal functioning. A metal protection prevents the escape of electromagnetic signals that can interfere with other devices close to it, the holes in the surface serve to facilitate ventilation and cooling of its internal parts that generate heat during its operation.

Power supplies are great examples of equipment that act as a Faraday cage

Continuing with practical applications, we started with lightning protection systems! The protection against electric rays in the building is covered on all sides by a conductive cable of electricity grounded in several points of this building, thus creating a protection for all people and objects inside this building, preventing the discharge of a lightning may affect its inhabitants.

Understand how the Faraday Cage works in a building!

How to create a Faraday Cage?

The creation of an experimental Faraday cage is very simple and can be done with common materials used daily in a residence. See the step by step to create a Faraday cage below:

Necessary material:

  • 1 aluminum foil
  • 1 Small radio

The first step if you are going to use a radio is to tune in to a station where the sound is as loud as possible and has the least amount of noise, this will facilitate the perception of signal loss. The second step is to wrap the radio in aluminum foil, if possible wrap the foil in several layers. Then you can see how easily the signal strength drops, and can even transmit only noise.


Although the Faraday Cage was discovered many years ago, it is still extremely useful and widely used today. Its application offering a protection barrier against unwanted electric and magnetic fields protects people from various risks and allows better use of electronic devices, preventing the exit or entry of signals that may interfere with their operation.