Electromagnetic interference or EMI is the noise or disturbance caused by mixing of signals or waves generated from electrical and electronic devices. This may happen through conduction which is when two or more conductive devices come in contact with each other. It also happens through induction, wherein devices are distantly placed but their signals interfere with each other. This interference produces a disturbing noise which may degrade the functioning of the device and reduce its efficiency. The same is applicable to assembled printed circuit boards. PCBs or printed circuit boards are the DNA of any electrical or electronic device, and hence PCB level EMI must be eliminated. This is done using PCB shields or EMI shields. The shield can be made of metal or a plasticized metal that can block EMI or waves coming from external devices. In the case of circuit boards, there are PCB shields which protect the board from EMI that can be produced from within the mounted components as well as external devices. EMC, on the other hand, is the electromagnetic compatibility of a device. This means the device’s capacity to withstand EMI and function normally. So, EMI and EMC as such are two sides of the same coin. This post discusses the difference between EMI and EMC which also highlights the significance of using EMI shields for PCBs.
Comparative Account: EMI vs. EMC
In a nutshell, EMI is the released radiation or waves, while EMC is simply the ability of a device or a circuit board to resist EMI coming from external sources. Here are some pointers to differentiate both these terms.
- As mentioned, EMC is the flip side of EMI, which means the former gives a measure of the amount of signal interference a device can handle, while EMI is the actual interference.
- EMC is used in testing a board or device for its ability to handle EMI, and is much a part of the testing and inspection process.
- EMC is often used in testing PCB shields used to cover circuit boards to protect EMI. This helps evaluate the quality of that shield and how much EMI it can block.
- EMC is also used for checking the ability of devices to operate well in the presence of EMI and multiple connected devices.
- By and large, tackling EMI and opting for EMC devices and circuit boards is crucial especially in sensitive applications. The level of EMI shielding would largely depend on the types of boards and components, frequency ranges involved, materials used and their dimensions and thickness, the volume or portion to be shielded, and so on.
In case you are an electronics, electrical, or electromechanical devices manufacturer or PCBA services provider, you must have good quality EMI shields especially for complex boards incorporated in sensitive devices. Some applications may have zero tolerance for noise, and hence these EMI shields play a crucial role. Ensure the shields are lightweight yet robust and flexible. Also, you must be able to remove them in case there is a need for component modification, reflow soldering, and so on, and put them back with as much ease. XGR Technologies offers SnapShot EMI shields that assures excellent shielding effectiveness from below 1 GHz to 12 GHz. They offer consistent isolation across a wide frequency range. These shields are super lightweight as they are made of plasticized metal, and they can be removed and reinstalled easily. The shields have non-conductive interior surface which reduces electromagnetic coupling with traces of the circuit, thus increasing safety, efficiency, and device functionality. You can get in touch with their team today to know more about these EMI shields.
