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EMI Enclosures
EMI enclosures, or “faraday cages”, protect sensitive electronic equipment from electromagnetic interference. EMI, or electromagnetic interference, is the magnetic field which is created by electrical currents; EMI can travel along wires, electrical circuits and conductors, while radio frequency interference (RFI) is radiated electromagnetic “noise” which travels through the air as radio waves. Enclosures surround the equipment which needs to be shielded, absorbing harmful EMI and RFI. Electronic equipment manufacturers and suppliers use EMI enclosures in applications such as circuit board housings, central processing units, laptops and mobile phone housings.
With small electronic devices such as circuit boards, laptops and CPUs, most problematic EMI comes from electromagnetic cross-talk between different components on the same board as EMI travels across wires and conductive materials. EMI shielding and insulation on wires and enclosures protects integrated circuits, electrical cords and many types of electronic equipment from electromagnetic interference, which might cause equipment to distort and slow information. Shielding sensitive electronic equipment from electromagnetic interference (and shielding high EMI-emitting equipment from contaminating other equipment) can be achieved by encasing EMI sensitive or EMI emitting circuits in EMI enclosures.
EMI enclosures are generally constructed from aluminum, stainless steel, nickel or copper alloys. Enclosures and shields built to block EMI need not be solid; perforated metals are often sufficient, as long as the surface’s holes are smaller and closer together than the electromagnetic waves it is meant to block. Microwave doors are a good example of this. As electronic equipment advances and electromagnetic and radio frequencies become higher and stronger, EMI gaskets are often used in conjunction with EMI enclosures for more robust protection. EMI gaskets create more robust EMI and RFI protection by preventing the leakage of EMI in or out of an enclosure through seams or gaps.
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