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How EMI Affects PCBs In Electronic Devices

Electromagnetic interference (EMI) can cause many problems regarding the technology we use every day. Specifically, printed circuit boards (PCBs) feel the wrath of EMI regularly. Thus, learning how EMI affects PCBs in electronic devices gives you an idea of what to look for and possibly fix to reduce this complication.

How EMI Affects PCBs in Electronic Devices

Simultaneous Switching Noise

With the constant switching of functions in PCB circuits, noise may turn into EMI. This ripple effect can ruin a PCB and cause timing errors that render the device useless. It can be even worse on larger PCBs, especially if they all flip at the same time and in the same direction.



No, these aren’t the giant metal rods that were on top of your grandparents’ television set and let them watch their syndicated game shows. However, they are areas on a circuit board that may emit EMI. These antennas may be in heat sinks or tall components within the device. If the board is mounted, the system chassis may have some antennas.


Return Paths

Transmission lines need to have a distinct path in which they travel. Think of your PCB like a stack of dominoes: you expect it to fall forward and follow the way you have set when you push the first one.

Ideally, a signal moves within a PCB, and it carries the circuit board freely with no interruptions. However, if the return path has an error, the route will detour the original source. If this occurs, there will be a significant amount of EMI.



Trace length and its layout are vital for reducing EMI in PCBs. Any manipulation with the traced design will cause the formation of those pesky antennas. To avoid this crosstalk phenomenon, you’ll want to keep your signals separate and return paths short. Also, prevent coupling as a result of having them too close at all costs.

Hopefully, this answers the question of how EMI affects PCBs in electronic devices. We take for granted how our electronics work on a daily basis. Most people are simply satisfied when the on button works, even if the process of getting it to work is a bit more complex.

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