Electromagnetic interference is a common issue that affects electronic devices of all types, from consumer electronics to industrial machinery.
If you’re manufacturing or importing an electronic device, it’s important to ensure it complies with regulatory standards for electromagnetic compatibility (EMC), such as FCC Part 15 in the US, or the EMC Directive in the European Union.
These standards are designed to ensure that devices do not cause electromagnetic interference in a shared environment, and that devices are sufficiently resistant to interference that’s emitted from other devices.
Below, we’ve explained what electromagnetic interference is, as well as the major causes of this common issue.
We’ve also shared the steps that you can take to ensure your device complies with all standards and regulations for electromagnetic interference, allowing it to receive the FCC/CE mark and go on the market.
For personalized assistance with EMI testing and compliance, you can contact us online or call our team at 866-540-5287 to ask a question or request a quote for your device.
What is Electromagnetic Interference?
Electromagnetic interference, or EMI, is noise or interference that affects an electronic device. It can cause a variety of issues, including degrading the performance of a circuit or preventing the affected device from functioning properly.
This type of noise or interference occurs as a result of emissions from other devices, which may affect the functioning of an electronic device. For example, when a TV receives interference, its signal may become weaker or disappear completely.
Similarly, certain types of equipment may fail to function properly when they’re subjected to EMI — for example, equipment may produce false measurements, or simply stop working.
When electromagnetic interference occurs in the radio spectrum, it’s usually referred to as radio frequency (RF) interference.
EMI is closely regulated in most countries. In the United States, the Federal Communications Commission (FCC) creates rules for electromagnetic interference such as FCC Part 15, which limits the level of electromagnetic emissions that a device can produce.
Similarly, the European Union has directives that set clear rules for a device’s electromagnetic performance, such as the EMC Directive and Radio Equipment Directive.
Our guide to electromagnetic interference goes into more detail about what EMI is, as well as common regulations that restrict electromagnetic interference for electronic devices.
Common Causes of Electromagnetic Interference
There are many causes of electromagnetic interference, both man-made and natural. Common causes of EMI include:
- Electronic devices and equipment. Almost any electronic device can produce EMI. It’s common for EMI to develop as a result of phones, radios, TVs, computers and industrial equipment, including devices that are non-compliant with EMI/EMC regulations.
- Power lines. High-voltage power lines can cause electromagnetic fields that may affect other devices by causing interference. These fields can affect radio signals and result in inaccurate readings from measurement equipment.
- Lightning. Lightning strikes can produce EMI in the form of both radiated emissions and conducted emissions. EMI from lightning strikes can affect power lines, communications equipment, and electronic devices.
- Radio and TV broadcast signals. Signals from radio and TV broadcasting can interfere with other devices that receive or use similar frequencies.
- Wireless devices. Devices that communicate wirelessly, such as Wi-Fi routers, phones and Bluetooth devices, can cause interference with other devices that operate on similar or nearby frequencies.
- Switching power supplies. Devices with switching power supplies, such as LED lights and computers, can potentially generate EMI that interferes with audio, video and radio equipment.
- Vehicle equipment and systems. Some electronic systems in vehicles, such as cars’ ignition systems, can generate electromagnetic fields that may interfere with electronic systems and wireless devices.
- Microwave ovens. Microwave ovens operate at frequencies similar to Wi-Fi networks (2.4 GHz). In certain cases, microwave ovens may emit EMI that interferes with Wi-Fi connectivity and devices that operate at similar frequencies.
- Industrial machinery. Heavy industrial machinery, including motors, generators and equipment that uses large electric currents, can generate significant EMI and disrupt nearby devices.
- Solar flares. In certain cases, EMI can develop as a result of solar flares. Solar flares, geomagnetic storms and other weather events can cause electromagnetic interference that may affect power grids and communications systems.
How to Achieve EMI/EMC Compliance for Your Device
- Understand the relevant standards. A variety of EMC standards apply to electronics, including FCC Part 15 and the EU’s EMC Directive. Before you begin lab testing, you’ll need to familiarize yourself with the relevant standards and regulations.
- Complete pre-testing for your device. Before lab testing, it’s common to pre-test your device to assess its electromagnetic performance. This testing can be performed with a lab partner or, in some cases, in your own facility.
- Test your device with an accredited lab. To achieve FCC and/or CE certification, you will need to test your device in an accredited lab. As an ANSI-accredited testing lab, we can test your device and help you comply with all relevant regulations and standards.
- If necessary, make changes to your device. If your device fails testing, you’ll need to make changes to its design to reduce its emissions. This may include making changes to your device’s PCB layout, adding shielding, or other changes. Our team can assist you with your device’s design, shielding and components to ensure you successfully pass your next round of lab tests.
- Affix the relevant compliance marks. After completing testing, you’ll need to prepare a Declaration of Conformity or seek certification for your device. Once successful, you can affix the FCC, CE and/or other relevant compliance marks to your device.
Our guide to the FCC certification process goes into more detail about how you can achieve full compliance with FCC regulations for your device.
Contact Us About EMI/EMC Testing and Compliance
Completing testing and achieving compliance with EMC standards is a key step in bringing your device to market, both in the United States and in other countries.
As an ANSI-accredited electronics testing lab, we can complete testing for your device and help you achieve FCC and CE compliance. Our team has extensive experience testing electronics of all types and purposes, allowing us to efficiently test your device and achieve authorization.
To talk to our engineers and compliance specialists about your device, or to request a free quote for testing, contact us online or call us at 866-540-5287.
