If you’re designing an electronic device, you’re likely familiar with the importance of complying with electromagnetic interference (EMI) and electromagnetic compatibility (EMC) regulations.

These regulations, which exist in all major markets, set limits on the amount of electromagnetic energy your electronic device can emit. They also set clear minimum requirements for immunity to electromagnetic energy to ensure your device can function properly near other devices.

Testing your device to verify that it complies with EMI and EMC regulations is a key step in the process of bringing it to market. 

EMI and EMC testing can seem confusing at first, with numerous standards to consider and a range of test procedures. However, it’s easy to understand once you’re familiar with what EMI and EMC are, what standards apply to devices, and how electronic devices are tested.

We’ve discussed all of this below, starting with the basics of EMI before covering common test methods and standards to keep in mind for your device.

If you need help with EMI/EMC testing, or if you have a question about regulatory compliance for your device, please feel free to contact us online or call us at 866-540-5287 to talk with our engineers.

What is Electromagnetic Interference (EMI)?

Electromagnetic interference, or radio-frequency (RF) interference, is unwanted noise that can originate from an electronic device or a natural source. When electronic devices are exposed to EMI, they may stop working normally or fail to function at all.

Man-made EMI develops as a result of electrical activity within a device. As the current inside a device changes, the wires and components inside can function like antennas, causing electrical noise to radiate from the device into the surrounding area. 

This noise is referred to as radiated emissions, and it can affect devices in a shared area. Other types of EMI, such as conducted emissions, can also develop. These forms of EMI are listed in the section below.

Controlling electromagnetic interference is critical for ensuring your device functions properly, is not a cause of disturbances for other devices, and meets regulatory requirements. 

Our guide to electromagnetic interference provides more information about what EMI is, how it can develop, and more. 

EMI Basics

Common EMI concepts include:

  • Emissions. Electromagnetic emissions are noise that’s generated by your device and transmitted into the surrounding environment. Emissions are radiated (travel via air) or conducted (travel via power or signal lines).
  • Immunity. Electromagnetic immunity refers to your device’s ability to operate when it’s exposed to noise from other sources. A device with high immunity will function normally in an environment with lots of interference, while a device with low immunity may fail.
  • EMI/EMC standards. EMI and/or EMC standards are performance requirements set by governments and/or standards organizations. Your device may need to meet a range of standards to gain a certain compliance mark or go on sale in a specific region. 

What is Electromagnetic Compatibility (EMC) Testing?

Electromagnetic compatibility refers to your device’s ability to operate normally when it’s in a shared electromagnetic environment, meaning an environment that includes other electronic equipment. 

A device that’s electromagnetically compatible can function normally in a shared environment without causing interference that affects other devices, or being affected by interference from other devices. 

In other words, it’s a responsible electromagnetic neighbor that doesn’t affect other equipment around it, and isn’t affected by other equipment. 

EMC testing is a process that’s used to determine if an electronic device meets the necessary electromagnetic compatibility standards. It involves testing a device in a lab, typically inside an EMC test chamber, and measuring its electromagnetic emissions and immunity. 

These measurements are compared against a standard — typically a government regulation or an industry standard — to verify that the device is compliant and suitable for the market.

How EMI & EMC Testing Works

During EMI and EMC testing, your device is monitored in a special environment to measure its performance. Its emissions are recorded and compared to a standard, as is its ability to work in an environment with significant electromagnetic fields.

Emissions testing involves measuring the amount of electromagnetic energy that’s emitted from your device while it’s operating. Your device is placed inside an anechoic chamber, with special monitoring devices used to measure its emissions.

As your device operates, measurements of electromagnetic energy are taken at a wide range of frequencies to identify and quantify its emissions. These emissions are then compared against a standard to determine if your device is compliant with relevant regulations.

Immunity testing involves measuring how your electronic device can operate when it is exposed to electromagnetic energy from an external source. 

Similar to emissions testing, immunity testing is performed in an anechoic chamber. Your device will be exposed to electromagnetic fields at a wide range of frequencies. The test environment is designed to mirror real-life scenarios that involve significant electromagnetic fields. 

Your device is compared against a specific performance standard to verify that it functions when exposed to interference and meets all testing requirements.

Regulations and Standards Related to EMI & EMC

All electromagnetic compatibility testing is performed against specific standards. These include regulatory standards, which your electronic device might need to meet in order to go on sale in certain countries, and industry standards set by professional organizations.

Some of the most common EMC standards and regulations include FCC Part 15 and European Union directives, such as the Electromagnetic Compatibility and Radio Equipment directives. 

FCC Part 15

FCC Part 15 is the most significant EMC regulation for devices sold in the United States. It sets radio frequency emissions and electromagnetic immunity standards for all devices that use the radio frequency spectrum, including consumer and industrial electronic equipment.

The FCC Part 15 rules apply to devices that can emit radio frequencies intentionally (referred to as intentional radiators) and devices that can emit RF waves as a result of their design (referred to as unintentional radiators).

If your device is subject to the FCC Part 15 rules, it will need to complete lab testing and receive FCC equipment authorization before it can enter the US market. 

We offer FCC testing services and, as a recognized Telecommunications Certification Body, can help you receive FCC certification for your device. 

EU Electromagnetic Compatibility Directive

The Electromagnetic Compatibility Directive, or EMC Directive, is a European directive that sets electromagnetic compatibility requirements for devices sold in the European Economic Area (all EU countries, plus Iceland, Liechtenstein and Norway). 

Similar to FCC Part 15, the EMC Directive requires testing for emissions and immunity. Devices that meet these requirements can affix the CE mark and go on sale throughout Europe. 

We offer EMC Directive testing and compliance services and can assist you if you intend to sell your device in Europe. 

EU Radio Equipment Directive (RED)

The Radio Equipment Directive, or RED, is a European directive that applies to radio equipment sold in the European Economic Area. If your device uses radio, Wi-Fi, Bluetooth, NFC or similar communications technologies, it’s likely subject to this directive. 

We offer RED testing and can help you ensure your device is compliant with all EMC regulations required for sale in Europe.

How to Improve Electromagnetic Compatibility

If your device fails to meet EMC standards, you will need to make changes to its design before retesting it. In many cases, a device can improve its EMC performance with simple changes to its internal design and the use of EMI reduction techniques.

Common methods for improving electromagnetic compatibility include:

  • Shielding
  • Filtering
  • Grounding and bonding
  • Changes to PCB design
  • Changes to components
  • Changes to enclosure design
  • Changes to cable routing
  • Software techniques

Our guide to reducing electromagnetic interference provides more information about how EMI can be managed and the methods listed above. 

If your device is currently non-compliant with FCC Part 15, a European directive, or other EMC regulations, our engineering team can help you identify potential causes and implement design changes to improve its performance and pass testing.

Feel free to contact our engineers for help if you would like to talk about your device and identify potential EMC improvements. 

Contact Us to Discuss EMC Testing & Certification for Your Device

If you’re planning to market your device in the United States, European Union or other markets, it’s essential to verify that your device complies with all EMC regulations and is certified to enter the market. 

As an ANSI-accredited testing lab and FCC-recognized Telecommunications Certification Body, we specialize in EMC testing and certification for electronic devices of all types and sizes. 

Our team can test your device, provide EMC recommendations, and help you get certification in the United States, Europe, Canada and other major markets. 

To request a quote for testing and certifying your device, or to talk to our experienced engineers about any part of the testing and regulatory compliance process, feel free to contact us online or call us at 866-540-5287.