GROUNDED: Your PCB, EMC/EMI, and SI Nuggets

I was reading a highly recommended design guide from a well-known manufacturer when I came across this advice:

"Place stitching capacitors across a split to provide a return path for high-frequency current."

Sounds reasonable, but does it actually work?

🧵:

In an ideal world, this makes perfect sense.

High-frequency signals would see the capacitor as a short circuit, perfectly restoring the return path.

But in the real world, things are different.

- Real components aren’t ideal.

- At high frequencies, capacitors become inductive after their resonance point.

- This creates a high-impedance path, blocking return current instead of guiding it.

The result?

EMI problems that could have been avoided.

The takeaway:

- Don’t compromise the return path.

- Never follow design rules blindly.

- Trust, but verify.

My gift to you to get a better grasp of EMI:

Get my free EMC/EMI design course: http://fresuelectronics.com/course

-Dario

Want to become an EMI Specialist?

Book a 1-on-1 live EMC/EMI training with me here: http://fresuelectronics.com/training