Switching Noise - EMC

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Switching Noise - EMC [Copy link]

What is EMC

EMC is the abbreviation of Electromagnetic Compatibility. In Japanese, it is often expressed as "electromagnetic compatibility" or "electromagnetic suitability", and there may be other expressions. It means "not to generate electromagnetic interference to other devices, and to maintain the original performance even if electromagnetic interference from other devices is received." It is called "electromagnetic compatibility" because it needs to have both performances.

"Not to generate electromagnetic interference to other devices" means that if this performance is not consciously ensured, it will cause electromagnetic interference to other devices. EMI (Electromagnetic Interference) is a term for electromagnetic interference (electromagnetic interference, electromagnetic obstruction). Since the emission of electromagnetic waves will cause interference, it is often used in pairs with the term Emission (radiation, emission). In terms of switching power supplies, it refers to the switching noise generated by on/off operation.

The opposite term is EMS (Electromagnetic Susceptibility). EMS is often used in pairs with Immunity. It is required to have the ability to withstand "no malfunctions or other problems even if EMI is applied."

EMI is divided into two types: conducted noise and radiated noise. These two terms are more often expressed in Japanese than in English abbreviations. Conducted noise refers to noise conducted through wires or PCB board wiring. Radiated noise refers to noise emitted (radiated) into the environment. For each of these noises, EMS has immunity requirements. Their relationship is as follows.

The above are the explanations and relationships of the relevant terms. In short, EMC is the key to whether EMI and EMS meet the standard specifications. The above explanations are summarized as follows.

Key points:

EMC (Electromagnetic Compatibility) refers to the performance of both EMI and EMS.

EMI (Electromagnetic Interference) refers to the interference to the environment caused by the radiation/emission of electromagnetic waves.

EMS (electromagnetic susceptibility) refers to the tolerance/immunity to electromagnetic interference (EMI).