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What is in?

• EMC should not be difficult and boring
• Why bother with EMC
• (Electromagnetic) Energy comes and go

EMC should not be difficult and boring

Since my first job in electronics, I have been told that Electromagnetic Compatibility (EMC) is hard.

And that’s it. No more details, no more explanations. When digging more, what I got was:

• It has always been hard
• There is only one way to work on it
• The only way to learn about it is by blood, sweat and tears

Well, it is not true

Yes, many people have learned it a hard way, and now they have mastered it.

But there are different ways

• Less painful
• With more than one approach
• By having fun and recovering the joy of learning

These people do not want to recognize it because they would be admitting that they took the long path

There is no shame in that, the truth is that the material out there does not make it so easy

Who am I?

My name is Ignacio de Mendizabal. I build resources to bring electronic products to the market as fast as possible, so you can turn your ideas into sellable products. Today, you can find these resources in:

• ​My Linkedin page​
• ​This Newsletter​
• ​Articles and guides on my website​

You are not alone

Struggling with EMC is very common among designers, no matter the experience. It is not taught at the University, while it is compulsory worldwide. Strange, uh? On the top of that, the Internet is full of information that seems contradictory and cluttered. When you are building a new product, you cannot afford to spend hours navigating all that documentation and crossing your fingers so it is accurate to use in your project.

If you feel frustrated and overwhelmed due to the pressure from the customer and the massive amount of information, you are not alone.

Why bother with EMC?

I am sure that sometimes you have wondered… Is this really something I should care about?

Yes, it is!

It is compulsory

When you sell a product in a specific country, everything you do should comply with the local regulations: taxes, staff, waste management, quality… and, of course, safety and Electromagnetic Compatibility.

The minimum you should care about is legal compliance.

There are two main moments when the EMC performance of a product is verified:

• The first time it is built. We verify that the product behaves as it is designed for.
• During market analysis. The authorities verify that the product is compliant after many years of production and after producing several units.

EMC requirements do not end once production is planned and started. Every new product placed in the market should comply with the latest EMC requirements.

Your product can stop working

You have already been there: after weeks of hesitation about whether to spend money, you take the leap and buy a new electronic gadget. You start using it and enjoying it, and then the gadget shows a blinking screen or some promised features do not work in all the situations you are using it. You claim it to the manufacturer, and they tell you that you are using it in very rare conditions.

And we both know what the consequences are

You never buy anything again from that manufacturer

The trust is gone

This kind of functional issue can be caused by non-designing for EMC or by not covering enough situations.

Yes, the product can pass the tests. The emissions can be under the limit lines. The approval stamp is there.

And still have functional issues

It steals time from other tasks

EMC problems show up in the worst moments:

• When you think that your design is finished
• When you have planned the Start of Production (SOP)
• When you have told the customer that there are just a few tests left

You have allocated mental space for other things, projects and ideas.

And then, bum! You find yourself firefighting to solve EMC problems

• Spending money on unplanned tests
• Going to the lab on Saturday since it is their only free slot
• Calling expensive consultants that help you to bounce ideas

Once you solve the problems, you are exhausted and without motivation for big projects

What would you be doing…

instead of spending time with EMC problems?

Energy comes and go

We know that energy does not come from nothing; it gets transformed. Mastering EMC is mastering energy: source (attacker), coupling mechanisms (path), and load (victim).

How does energy flow?

Electromagnetic Energy can flow in guided media (cables) and unguided ones (air). No matter the propagation media, we need to keep all the energy under control. Without entering a world full of complex equations, these concepts are the most important ones:

• Electromagnetic energy flows in waves, which have amplitude, frequency, and phase
• Wavelength depends on the frequency and the propagation media (permittivity)
• The concepts long or short are relative to the wavelength

In EMC, we check both guided (conducted) energy and unguided (radiated) energy

Emissions and Immunity

Every electronic product needs to fulfill two requirements:

• It should not disturb other electronic products around it (low emissions)
• It should work fine even in an environment of high disturbances (high immunity)

Emissions and immunity performance are somehow interconnected. A system that is poorly designed and radiates is highly likely to struggle to pass immunity tests such as ESD or bursts.

Tests

EMC tests are divided into four categories:

• Conducted Emissions (CE): we measure the noise over the power and communication cables.
• Conducted Immunity (CI): We inject pulses over the cables to check whether the system continues to work as usual. The degree of performance accepted will depend on the acceptance criteria.
• Radiated Emissions (RE): we measure the noise (unwanted emissions) over the air. We look for the position (angle) where the emission level is maximum, as well as for the position of the antenna (polarization and angle) where it is maximum.
• Radiated Immunity (RI): we apply electromagnetic energy (radiation) over the electronic system and we check if it keeps working. Similar to conducted immunity, the degree of performance accepted will depend on the acceptance criteria.

What is next

• Dig deeper into the topics with the online articles​
• Download the EMC guides and start building your laboratory
• Share your thoughts about this content and tell me what you would like to learn using this form or replying this email.

See you!

Your EMC buddy

Ignacio

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