Electrostatic shielding

Priyanka Devan
Updated on

Electrostatic shielding is a method of shielding or protecting a particular region or space or any sensitive building/instrument from the effect of the external field produced by an electric charge. For example, there is an instrument used to measure high voltage called CRO. It is kept inside a hollow conductor or cage called the Faraday’s cage. According to the practical demonstration of electrostatic shielding, there is no electric charge inside a closed conductor when there is no charge inside it.   Michael Faraday took a high-voltage generator, prepared a large wired cage supported on insulators, and sat inside the cage with gold leaf electroscopes, which were electric field detectors.  When this cage was charged with an induction machine, Faraday observed no deflection in electroscopes. This could sit safely and comfortably inside the cage. So, hollow conductors work as a protective layer for humans and devices from mighty electric fields. These hollow conductors or Faraday cages are used to obstruct electric charges from setting at one place by establishing an electric field beyond their immediate vicinity and surrounding the charges with a Faraday cage and connecting this cage to the earth. 

Faradays cage

Faraday cages shield their contents from static electric fields. An electric field is a force field surrounding a charged particle, such as an electron or proton.

These cages often look distinctly, well, cagelike. Some are as simple as chain-link fences or ice pails. Others use a fine metallic mesh. Regardless of their exact appearance, all Faraday cages take electrostatic charges, or even certain types of electromagnetic radiation, and distribute them around the exterior of the cage.

Electromagnetic radiation is all around us. It’s in visible and ultraviolet light, in the microwaves that cook our food and even in the FM and AM radio waves that pump music through our radios. But sometimes, this radiation is undesirable and downright disruptive. That’s where Faraday cages come in.

As a Faraday cage distributes that charge or radiation around the cage’s exterior, it cancels out electric charges or radiation within the cage’s interior. In short, a Faraday cage is a hollow conductor, in which the charge remains on the external surface of the cage.

Applications of Electrostatic shielding

  1. Electrostatic Shielding in Cars: It is safe to sit inside the car during a lightning thunderstorm. It is because the metallic body of the car works as an electrostatic shield. The concept of electrostatic shielding is used in wires carrying audio signals.
  2. Electrocution: To protect themselves from being killed by an electric shock or electrocution, linemen wear suits that are made of Faraday cages. Elevators in buildings act as an electrostatic shield as the cell phone, radio, and audio signals get shielded. The coaxial cables in the outer conductor are connected to the earth to provide electrostatic shielding to the signals that are transferred by the central conductor.

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Electrostatic Shielding and Its Applications

Electrostatic shielding is defined as the phenomenon which is observed when a Faraday cage is used for blocking the effects of an electric field. The use of the cage is to block the effects of an external field on the internal content.

It’s because when an electric field operates on a Faraday cage (box made of copper), the charges with a cage rearrange themselves to directly counterbalance the field, and hence, the shield (protects) the internal of the cage from the external electric field.

Electrostatic shielding is the phenomenon of protecting a certain region of space from external electric field . The electric field inside a conductor is zero. therefore to protect delicate instrumats from external electric field , we enclose them in hollow electric fields, we encloses them in hollow conductor.

This is called electrostatic shielding. Faraday cage is an instrument used to demonstrate this effect.

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