How Electromagnetic Shielding Works To Stop EMI

From your phone to your TV to your microwave to any number of other electronic devices, electromagnetic interference (or EMI) can interrupt service, destroy data, or even cause your devices to fail, crash, and figuratively burn. Other electronic devices, natural forces such as the sun, and even signal-jammers who interfere with electronic communications all generate EMI. Confused and wondering how EMI can affect you? Here’s what EMI is, why it’s bad, and how electromagnetic shielding works to stop EMI.

EMI Is Everywhere

Electromagnetic interference occurs when one electric current causes a disruption to another. EMI can manifest itself as interference with a TV signal, causing the image and sound to break up or disappear entirely. More commonly, you’ve probably experienced EMI when your cell phone dropped a call or you heard noise on the radio while using another electric tool. In that vein, EMI can come from anywhere—and that means anywhere. Solar flares, lighting storms, the Northern Lights, and even other planets can cause EMI. So can microwaves, routers, toasters, and other appliances. Sometimes the same kinds of devices can cause EMI in others—for example, a bank of computers. Again, EMI is everywhere—so how are your devices protected from it?

Inner Protection

An outer case as well as an internal series of covers made of magnetic or conductive materials that reduce the electromagnetic field protect the delicate parts and pieces of your electronic devices. Some materials used to manufacture such covers include screens, wires, metal foam, metallic links (made from copper, aluminum, or nickel-iron alloys), rubber, and plastic.

All this shielding prevents outside EMI sources from affecting the inner workings of the device while providing a barrier that keeps the device’s own EMI from influencing or damaging other devices. Shielding keeps radio waves, static, and electromagnetic fields from bumping into each other by absorbing them and then draining them away via a ground connection. If a device has batteries or plugs into a wall, it likely contains an EMI-combating cage or covering inside.

Shielding Prevents EMI. So What?

The applications of EMI shielding go beyond ensuring you have uninterrupted calls, Internet service, and movie nights. EMI shielding has public, industrial, and even military applications that can prevent everything from petty annoyances to life-threatening signal intrusions. In the medical field, shielding prevents the disruption of pacemakers and other implanted devices, which could threaten the life of the patient. For that same reason, external medical monitoring equipment must also be protected, as should communications devices (phones, radios, and so on) used by doctors, nurses, paramedics, and other medical personnel.

And when you’re pondering how electromagnetic shielding works to stop EMI, don’t forget the military. It has a special need for such protection and security, needing to prevent unfriendly sources from compromising, jamming, or otherwise interfering with GPS, targeting, and communications devices. In short, protection from EMI is serious business.