Types of Electromagnetic Interference

What’s EMI? Electromagnetic interference (EMI) is electronic “noise” that generates from natural and artificial external sources and interferes with an electrical circuit or path. Also referred to as radio frequency interference, EMI can lead to anything from poor electronic device performance to physical damage, with the potential for component malfunction or full system failure. Learn more about the types of EMI interference, its effects, and how to prevent it.

Types of Electromagnetic Interference

EMI (electromagnetic interference) occurs between three parts: the source, path (electrical transmission method), and receptor (victim of the interference). EMI can travel from the source to the receptor by several path types.

Radiated EMI

Radiated EMI occurs when an electrical device serving as the receptor picks up on a far-off radio frequency. The source of such frequencies can be another electronic device or high-powered components like transmitters. Either way, this EMI negatively impacts the receptor and its performance. For example, your Wi-Fi signal may fail when someone uses an outdated cordless phone. Radiated EMI covers both broadband EMI, when malfunctioning devices affect a broad spectrum of radio frequencies, and narrowband EMI, when devices like radio transmitters impact a small range of frequencies.

Coupled EMI

With two transmission methods, coupled EMI impacts a receptor when it and the power source are in close proximity but not physically joined. Capacitively coupled EMI happens when parallel conductors are extremely close and, between them, accumulate a capacitive electrical charge. This type of coupled EMI affects circuit boards or long, closely grouped wires. The second transmission method, inducted or magnetically coupled EMI, is like a hum on an audio line when audio and power cables are located close by one another. When inducted EMI occurs, the magnetic field from one conductor induces interference in another.

Conducted EMI

When an electronic device includes a physical path for electricity to transfer from source to receptor, as is the case in power transmission lines, conducted EMI can occur. Large motors and power supplies like clothes dryers and treadmills can cause EMI in systems like computers, resulting in circuit reboot.

What Are the Effects of Electromagnetic Interference?

EMI sources in data centers can be a challenge to detect. When they go unmanaged, however, EMI can impact cables, hardware, and servers, even exposing your data center to electromagnetic field (EMF) attacks.

Data center cables can experience voltage surges when unintended currents generate from nearby EMFs. In turn, this interference with the cables can impact data center functionality. EMI can also interrupt remote receivers that identify data packets, causing network congestion due to the retransmission of the dropped packets. Low-frequency EMI, in particular, is harmful to data center hardware, potentially resulting in complete solid-state drive (SSD) and hard drive data loss.

How to Protect Against EMI

Cheaply or unskillfully made components often lack the necessary shielding or sufficient product testing to effectively prevent EMI. The same can be said of counterfeit electronics. Also, while numerous countries worldwide have set EMI standards for their electronics, that doesn’t mean that internationally manufactured devices will adhere specifically to U.S. standards. The U.S. Federal Communications Commission (FCC) mandates that domestic companies test their electronic devices to ensure they meet U.S. emission standards, which aim to prevent devices from generating EMI that would impact other devices.

To successfully avoid electrical interference, you should:

  • Source quality electronics. Working with parts and devices from suppliers with proven track records is one of the most important ways to increase your chances of receiving quality products that safeguard against EMI.
  • Use current filters and error corrections. Today’s advancements lessen the chance that EMI from other devices will impact your components.
  • Remember EMI in high-speed wired network planning. Wired networks require separation between data and power lines. Using twisted pair shielded cables can also enhance signal quality.
  • Include wireless network planning. To successfully plan your wireless network, take into account the number, location, and power of any power transmission sites and lines as well as radio frequency sources close by.
  • Swap out copper for fiber-optic cables. EMI doesn’t affect fiber-optic cables, making them an ideal alternative to copper cables.

Contact MH&W for Help Today

EMI results in unintended interruptions or damage to electronics. Taking precautions, such as using quality electronics and shielding, can reduce the likelihood of EMI. At MH&W International Corp., we understand how detrimental EMI can be. We’ve delivered high-performance magnetic parts and cores since 1964, specializing in innovative noise-filtering solutions within filters and chokes for solar, wind, EV, VFD, and motor applications. To learn more about our products for effective EMI prevention, contact us today.

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