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If your electronics have failed FCC/CE certifications, you might want to read this.
It could save your design now, or in the next round of testing, particularly for radiated and conducted emission or immunity.
The reason your device failed the test is that its emissions exceeded the allowed limits.
Emissions are generated by time-varying currents, not voltage.
This means that wherever you have currents, you have emissions.
The question is: how much, and from which source?
Essentially, emissions can be divided into two types:
- Emissions from differential-mode currents.
- Emissions from common-mode currents.
The way you design your PCB, along with the entire system, determines how these currents, and their associated emissions, behave.
In other words, this is a design problem.
You can (and need to) address it before the design phase is complete.
If you went to the EMC test without planning for this, your solutions are now limited and expensive.
Now, how to tackle this at the source?
It starts with how you design your electronics.
If your electronics are poorly designed, the system will likely amplify that.
That's why you need to start from there, from your PCB.
At this stage, the issues are usually quick and inexpensive to fix.
The key is understanding how your design choices relate to the emissions shown in the test results.
Simple, not easy.
-Dario P.S. Want to make passing EMC tests faster a routine?
I put together a guide on the top 10 PCB design mistakes for EMI control.
It’s practical, hands-on, and built to help you pass EMC tests faster.
Grab my new EMI Control Guide here: