What are EMI and RFI & Where They Come From?

What are EMI and RFI & Where They Come From?

Have you ever wondered what EMI/RFI means or from where do these electrical interferences come from? Possibly you know that EMI and RFI sources are responsible for harming the performance of the circuit. But exactly these terms EMI/RFI and EMC mean. In this post, we’ll find out what EMI and RFI mean, as well as their common sources.

What are EMI and RFI?

First, you need to know that EMI and RFI are not the same things. EMI stands for electromagnetic interference, while RFI is radio frequency interference. EMI means any electrical disturbance that causes performance failure in a component. RFI, on the other hand, is a disturbance that occurs within the radio frequency spectrum. Both EMI and RFI are responsible for impacting the electrical components and can cause a disturbance in another piece of electrical equipment.

In other words, EMI is any frequency of electrical noise, whereas RFI is electromagnetic conduction or electromagnetic radiation emitted from an external source. The unwanted signals and waves produced by electronic devices negatively affect other electronic devices. Moreover, the interferences from outside cause malfunction in electronic devices. This means that both ingress and egress of EMI and RFI cause disturbances.  Both these interferences can cause many temporary, as well as permanent issues.  The problems caused by EMI/RFI include mobile phone signal loss, hard drives crash, pacemaker failure, and more.

To prevent EMI and RFI from causing disturbances, EMI/RFI Shielding technique is used. The shielding agents like acrylic-based sprays are most commonly used for protecting the device’s internal components. The pure metals like nickel, silver, and copper are sprayed on the plastic electronics housings which helps in preventing EMI and RFI interference. Besides spray, these shielding agents also come in the form of paints and brush on coatings.

What are the Sources of EMI and RFI?

Now you may ask from where EMI and RFI come. Because Electromagnetic Interference can arise from several sources, the sources can be categorized in a number of ways. The most common way of distinguishing EMI is by the way it was created. This means that the sources of EMI and RFI can be either naturally occurring or man-made.

Man-made EMI arises from other electronic circuits, such as transmitters, transformers, electric motors and generators used in the industries, as well as cellular networks towers. The sources of EMI are also present in our homes, such as microwaves, electric blankets, electric bug killers, heaters, baby monitors, and Wi-Fi or Bluetooth devices. The natural sources of these disturbances include lightning, solar flares, snowstorms, and other atmospheric types of noise all contribute. This means that any source, natural or man-made that can disrupt the electrical components of a device is considered as EMI/RFI.

To deals with problems of noise emission and noise immunity of electronic devices, various types of interference shielding products are used. To achieve Electromagnetic Compatibility (EMC), EMI and RFI shielding products like Foil tapes, Knitted mesh, Conductive rubber, Mesh/elastomer, and many more are easily available.

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About the Author: Angelique Chrisafis

Angelique Chrisafis is the Guardian's Paris correspondent. She is responsible for churning out quality articles based on her research while keeping an eye on the tech world. She likes technology, gadgets, and food. Works as an individual contributor to the team.