Why Are EMI Filters Important?

EMI, or electromagnetic interference, is any electrical or magnetic force that impedes signal flow. This interference can degrade the quality of communications transmissions, hinder the flow of electricity, and even damage the affected equipment. Both narrowband interference, which is caused by human activity, and broadband emissions, which can be either human or naturally caused, are forms of EMI.

EMI filters are devices and modules that directly counter the effects of interference to stabilize the electrical flow or signal transmission, thus protecting the integrity of the system or device.

Dangers of EMI

Uncontrolled EMI presents many dangers to both the electrical devices being impacted by the interference and the signal itself. Damage can be either temporary or permanent, but even temporary effects can be catastrophic if it interferes with critical components to everyday life, such as medical equipment or military communications. EMI can:

  • Cause damage to electronics: Specifically, residential and commercial electronics, such as microwaves, refrigerators, and television systems, are vulnerable to damage from EMI. Temporary interference may cause systems to malfunction and over- or under-power devices, which can degrade the machinery’s mechanical components.
  • Cause equipment to fail: When EMI blocks communication signal transmissions, it can make cell phones and other mobile devices fail. While this may be simply inconvenient in many residential contexts, it can be costly for employees and businesses and outright dire for hospitals, municipal facilities, and military installations. Some medical devices potentially vulnerable to EMI include pacemakers, hearing aids, and life support sensors.
  • Disrupt wireless communication: EMI can interfere with large-scale radio and television transmissions by inhibiting satellites. Commercial telecommunications systems may also suffer from unreliability, poor sound quality, and slow performance.
  • Interrupt power supply: EMI can be powerful enough to interfere with the power grid and localized electricity stations. It also can cause power failures for independent systems, such as military installations, mobile and remote sites.
  • Result in data loss and electronics malfunctions: When computers and cloud-based interactions are impeded, even for just a second, data can become lost and unrecoverable.

Each of these problems can have great consequences for the systems to which they are a part.

Where Does EMI Come From?

Like we briefly discussed earlier, there are two main sources, or types, of EMI: narrowband and broadband. Another way to categorize EMI is into human-made and natural sources of interference.

Man-Made EMI

In complex electronic systems or systems in crowded environments, such as hospitals or cities, technology can interfere with itself, resulting in man-made EMI. For example, some components within a computer may cause EMI, which interferes with more vulnerable components in the same computer. Alternatively, actively working medical equipment can interfere with sensors in a hospital room. Interference from other electronics in a shared space can be common.

Other man-made sources of EMI include more industrial ones, such as powerlines, generators, television, radio and satellite transmission, and operating systems for railroads and mass transit.

Natural EMI

Natural sources of EMI come from weather and cosmic effects. Common origins of EMI include lightning strikes, heavy storms, and cosmic noise. Even static electricity can cause natural EMI.

<Explore the difference between EMI and EMC.>

Choose Captor Corporation for EMI Filters

EMI filters can reduce or eliminate this issue. At Captor Corporation, we specialize in creating standard and custom EMI filters for a range of electronic devices, including aerospace and military EMI filters. Each of our products is designed to keep critical systems performing in optimal and consistent condition. Browse our EMI filters portfolio page to learn more about our custom EMI filter experience.

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