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Meet Magnetic Shields

RFI Shielding

Magnetic shields contain magnetic interference from within or isolate interference from without. This is the simplest definition of the roles that magnetic shields play. Of course, this definition is insufficiently descriptive to give anyone a meaningful understanding of what magnetic shields do and how they do it. While a truly thorough understanding of the topic would have to involve a crash

It’s important to remember that magnetic shields do not block or eliminate interference caused by magnetic fields; that is physically impossible. Instead, magnetic shields can attract magnetic fields and direct them away from whatever it is the magnetic shield is being used to shield. A material that is capable of this is considered to be magnetically permeable. Bearing that fact in mind, thinking of a simple example situation in which a magnetically shielded environment would be beneficial can be helpful in understanding the concept of magnetic shielding and magnetic interference.

A common experiment used to help students understand magnetism involves placing a bar magnet under glass or plastic and then sprinkling iron shavings over the glass. Distinct line patterns emerge in varying degrees of thickness and distance from each other. Believe it or not, but even this experiment is affected in subtle ways by magnetic fields, both natural and artificial. The positioning of the iron flakes could vary depending on how close the experiment was conducted to certain kinds of electrical devices. The results could also vary depending on the country or even city in which it was performed. In order for this experiment to be conducted independent of interference, it would have to be conducted in an enclosure that was isolated from ambient magnetic interference.