EMC TESTING: THE BEGINNER'S GUIDE

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New to EMC (electromagnetic compatibility) testing? Need to polish up your knowledge? This beginner's guide to EMC gives the concise information you need to identify, prepare for and ultimately pass EMC testing.

In this guide, you'll learn how to find the EMC standards that apply to your product, what the emissions and immunity tests are that you'll need to pass, how to prepare for testing, how to find good EMC test labs, typical pricing and much more.

The beginner's guide to EMC is an in-depth tutorial on all aspects of EMC testing. This guide covers the fundamentals of everything you need to know to be able to navigate, prepare for and pass EMC testing.

Here's what we'll cover in this chapter:
  • Learn what electromagnetic compatibility (EMC) testing is
  • Discover the poor first time pass rate average
  • The 5 reasons manufacturers care about EMC testing
  • The history and future of EMC testing

Read on below!

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What is Electromagnetic Compatibility (EMC) Testing?

Electromagnetic Compatibility (EMC) testing is the process of evaluating an electronic device to ensure it does not emit an excessive amount of electromagnetic interference (EMI), and that it can operate correctly in the presence of EMI in its environment. These emissions—both radiated and conducted—must fall within defined regulatory limits to avoid interference with other equipment.

EMC testing includes two core objectives:

  1. Emissions Testing – Ensuring your device does not generate unwanted interference.
  2. Immunity Testing – Confirming your device continues functioning as intended when exposed to external electromagnetic disturbances.

Most countries require products with electronics to pass EMC testing before they can be legally sold.

Tip: The term "electromagnetic compatibility" refers to a device's ability to function satisfactorily in its electromagnetic environment without introducing intolerable interference to anything in that environment.

Common Emissions and Immunity Tests

Before diving into testing preparation, it’s helpful to know what types of tests your product is likely to undergo. Below is a high-level overview of the main EMC emissions and immunity tests. These are covered in much more detail in later chapters.

Emissions Tests

  • Radiated Emissions (EMI) Tests: Measures electromagnetic energy unintentionally emitted into the air. Tested in an anechoic or semi-anechoic chamber using antennas.

  • Conducted Emissions Tests: Measures unwanted RF energy that travels along power or signal lines, typically below 30 MHz.

Immunity Tests

Each test applies differently depending on the product category and the standards it must meet. These tests are typically defined in standards like IEC 61000-4-x and CISPR 11/22/32.

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Why EMC Testing Matters

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Why EMC Testing Matters

1. Preservation of the electromagnetic spectrum

We rely on a finite electromagnetic spectrum for radio, wireless communications, satellite navigation, and more. Even unintended emissions from electronic circuits can pollute these frequencies, causing cross-interference.

2. Safety in Critical Systems

Failures in devices due to EMI can cause serious harm, especially in sectors like medical, military, automotive, and aerospace. EMC standards are built to safeguard the performance of safety-critical equipment.

3. Product Performance and Reliability

EMC issues can degrade sensitive electronics, from sensor readings to wireless signals. Thorough EMC testing helps identify and resolve interference sources early—improving product reliability and reducing returns.

4. Regulatory Compliance & Legal Risk

Regulators such as the FCC (US), CE (EU), ISED (Canada), and others enforce EMC standards. Non-compliance can lead to fines, product recalls, and even bans on market entry.

5. Market Access & Customer Trust

EMC testing fines

Passing EMC tests ensures smoother certification and faster time-to-market. It demonstrates professionalism and builds trust with distributors and customers worldwide.

What is the EMC Testing Pass Rate?

Only ~50% of products pass EMC testing the first time, according to one of the largest studies by Intertek Labs.

A failed test can delay time-to-market by days or months, making proper preparation critical.

 

In this guide, we’ll show you:

  • How to determine applicable EMC standards

  • The typical emissions and immunity tests

  • How to prepare effectively (including pre-compliance testing)

  • What labs look for—and how to choose the right one

  • Pricing ranges for different regions and products

A Brief History of EMC

  • 1882 (Germany): First known EMC regulation for telegraph systems

  • 1899 (UK): The Lighting Clauses Act to stop lamps from interfering with neighbors’ lighting

  • 1938 (US): FCC emission rules for transmitters

  • 1989 (US): Standardization of general-purpose emission limits

  • 1992 (EU): Introduction of the EMC Directive to harmonize compliance across member countries

EMC rules have evolved in response to real-world problems—protecting both the spectrum and user safety.

The Future of EMC Testing

1. Global Standardization

Driven by IEC efforts, more countries are aligning with international standards (e.g., CISPR, IEC 61000 series).

2. Expansion of Immunity Testing

Regions like Australia, New Zealand, and parts of Asia are moving toward the EU model that mandates both emissions and immunity testing.

3. Stricter Test Lab Accreditation

Governments now require labs to be accredited (e.g., FCC rules for US transmitter certification). Smaller labs may be phased out in favor of those with deeper compliance capabilities.

4. Increased Testing Costs and Complexity

As test requirements increase, manufacturers should expect longer test cycles and more detailed planning to meet both emissions and immunity thresholds.

Coming Up Next

This guide is just the beginning. To fully understand how to prepare your product for successful EMC testing and global compliance, continue reading the rest of the guide:

Each chapter is designed to walk you through the entire process with practical tips, expert advice, and actionable tools to help you succeed.

That's it for the first part of the beginner's guide to EMC. Remember to share this with any friends or colleagues that will find it valuable. Also leave any comments or questions below!

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  4. Very interesting indeed, going to read through your papers and compare to my own experiences here in Canda.
    Thanks,
    Wayne

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  5. You mention above that “in Europe, both emissions and immunity testing are mandated.” For any product required to meet the European EMC Directive, this is not true. In reality EMC testing is an option only. Compliance with EMC test standards can only, at best, only give a presumption of conformity with the Directive.

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      Hi John. yes you have a point – will fix up the article to highlight that emissions and immunity testing is only the preferred method of proving/ensuring compliance with the EMC directive for *most* legitimate manufacturers. I’m impressed that your comment comes from someone who is involved with an accredited EMC lab. Normally this information is obfuscated by labs in an effort to get more business.

      Reply

      1. Hello Andy. I found your information to be well thought out, well written and useful. I wasn’t not looking to do anything other than read it. 🙂

        Reply

  6. Hi Andy,

    Excellent work. Congratulations. Talking of obfuscation, are there any figures on expected costs at a testing lab? I understand that there may be a variation in fees, and I am looking at a product that has been well tested and shielded, before going to the lab. The lab requires a few hours (1/2 day) to test and certify, say to fulfil ICNIRP or FCC Chapter 15 standards.

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  7. Andy,
    You reference broad sources of nomenclature, requirements, and testing facilitation. It’s what I need to become a wireless shark. I came from old HP EMC labs and the goodies in your chapter 8 will help me to sharpen my senses to improve pass rates. If ever you come to the SF bay area, look me up and we can swap stories.
    Thank you.

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  8. Hi,
    If I have FCC, RoHS, and CE certifications, will I need any other certifications for the device that has bluetooth function, but is not actual bluetoth device. I mean, bluetooth has peripheral function on it.

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  11. What are the advantages of using Anechoic chamber over GTEM cell ? Precompliance testing testing with GTEM cell is comparatively less but should we go for GTEm cell for precompliance testing.

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      If you’re talking about a smaller pre-compliance semi-anechoic chamber vs. a GTEM, the benefits (of a chamber are):
      1. Can accommodate larger EUTs
      2. Better low frequency (<200MHz) correlation to fully compliant chamber
      3. Less sensitive cable positioning
      4. Don't have to deal with cable penetrations through GTEM walls to auxiliary equipment
      5. GTEM measurements are harder to correlate to fully compliant chamber (need to measure in 3 axis and use software to average)

      But as you say, GTEMs are cheaper. I would go with a compact semi-anechoic chamber if your budget allows for it.

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      1. Gtems are accepted for full complience in some standards. My current company use a calibrated GTEM for immunity testing upto 75V/m & upto frequencies of around 6Ghz. For the higher frequencies, and the emissions work we use our AC (Anechoic Chamber) or our large SAC (Ssemi-anechoic Chamber). All are calibrated and accredited by UKAS. (United Kingdoms Accreditation Service.)

        In my experience getting the support equipment out of the GTEM is often easier than getting it out of the AC, as the lenght of cables need to be longer. Of course each to their own.

        If you are only going to test EUTs of around 50cm x 50cm x 50cm then I think the GTEM is the best option.

        The cost of the chamber/GTEM isnt the only consideration the running equipment for a GTEM will be less that that of an AC, the antennas are less for the GTEM as they are fixed, hence the cableing etc is much simpler.

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  12. Hi Andy,
    I’m impressed with your guide…:-) I have 3 years of experience in EMI/EMC still I can find more that I don’t know. Thanks for showing me your views. Please add more posts..:-)

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  13. Sorry, real novice here and trying to make sense of the new Regs. Could anyone confirm if testing is required when the handbrake of a vehicle is applied (vehicle immobilised) and system operated. I read this in VCA documentation but now desperately trying to relocate it.

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  14. Regarding the need to register products on the ACME database for Australia. I assume if a device is compliant to the EMC standard (IEC 60601-1-2), issuing a DoC and registering the product is all that is required. Do you agree? Can you provide additional information to clarify?

    Thanks

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  15. Thanks for the publishing.
    Is switch racks consists of dry typr transformer,cpt,indication lamps etc. are required to be having EMC test?
    Kindly advice a statement to justify why it is not applicable .

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