EMC is the abbreviation of Electromagnetic Compatibility. It means "no electromagnetic interference to other equipment, and the original performance is maintained even if electromagnetic interference from other equipment is received". It is called "electromagnetic compatibility" because it needs to have both performances.
"Do not cause electromagnetic interference to other equipment" means that if this performance is not consciously ensured, it will cause electromagnetic interference to other equipment. EMI is a term that represents electromagnetic interference. Because the emission of electromagnetic waves can cause interference, it is often used in pairs with the term Emission. In terms of switching power supply, it refers to the switching noise caused by on/off operation.
The opposite term "even with electromagnetic interference from other devices" is EMS - Electromagnetic Susceptibility. EMS is mostly used in pairs with Immunity (tolerance, immunity, exclusion capability). It is required to have the ability to withstand "even if it is subjected to EMI, it will not cause problems such as malfunction."
EMI is divided into two types: Conducted Emission and Radiated Emission. Conducted emission refers to noise that is conducted through wires or PCB board wiring. Radiated emission refers to noise emitted (radiated) into the environment. For these noises, there are immunity requirements in EMS. Their relationship is as follows.
