shieldingelectrostatic is a phenomenon that causes the electric field, inside the conductors in electrostatic equilibrium, is null. Electrostatic shielding protects electronic circuits from damage and malfunctions when exposed to external electrical fields.
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How does electrostatic shielding work?
The materials conductors, such as iron, silver or gold, have a large amount of electronsfree. such electrons they are able to move, suffering almost no resistance inside the conductors. This freedom makes these electrons able to rearrange themselves, almost instantaneously, whenever the conductor is exposed to a fieldelectricexternal.
In an insulated conductor, this reorganization of electrons keeps it neutral, but with charge accumulations in different regions of it (this condition is called polarization), in addition, in its interior, the electric field will be null.
It is important to note that the electric field will only be completelynull inside the conductors when they are in balanceelectrostatic. Electrostatic balance is characterized by the resting condition of electrical charges, therefore, it is not valid for situations in that there are electrical currents inside the conductors, or when an external electrical field is applied to the conductor and variable.
Also, when a conductor is in electrostatic balance, its loadsliquids (excess loads), are distributed throughout the your surface, so the amount of charges per area, known as densitysurfaceicialof loads, be constant.
It is for this reason that the phenomenon known as power of the tips — conductors that have sharp regions (of very small areas) need to compensate for the surface charge density. To do so, they accumulate a large amount of them. This makes the tips more likely to produce sparks, as is the case with lightning rod, used to facilitate the passage of lightning.
Electrostatic shielding applications
Electrostatic shielding is a phenomenon of great use to electronics, since, through it, it is possible to isolate electrical circuits from possible effects caused by interference from electrical fields external. The most famous application of electrostatic shielding is the faraday's cage— a metal cage whose main function is to protect its interior from electrical discharges.
Let's check out other uses of electrostatic shielding:
Conductor wires – electrostatic shielding is used in audio cables in order to protect the transmitted signal from interference caused by external electric fields.
Cars – the interior of vehicles is “safe” against lightning or other electrical discharges, as long as the passengers are inside the car, as its body is metallic.
conductive clothing – are clothes generally made of stainless steel and other materials, used to protect workers who deal directly with high-voltage networks. They work just like a Faraday cage.
![Faraday's cage has been used for a large number of experiments on electricity.[1]](/f/0f9add6e6549d364017c5c12a75d7f3d.jpg)
Experiment on electrostatic shielding
There are a large number of experiments that can be done to observe the action of electrostatic shielding. One of the simplest ways to make this observation is with the use of a metal sieve. Want to know more about this experimental setup? Read our article about electrostatic shielding, in the çanal of andducator.
Most of the experiments suggested in internet articles talk about using aluminum foil, pans or even a microwave oven to interrupt the cell phone signal. However, such phenomena do not actually illustrate the electrostatic shielding, but the electromagnetic shielding of radio waves.
Image credits
[1] commons | Antoine Taveneaux
By Rafael Hellerbrock
Physics teacher
Source: Brazil School - https://brasilescola.uol.com.br/fisica/blindagem-eletrostatica.htm