Customary that, EMC including EMI (electromagnetic interference) and EMS (electromagnetic susceptibility) aspects.

     Electromagnetic compatibility (EMC) refers to the equipment or system in its electromagnetic environment does not meet the requirements of their environment to run any equipment generates intolerable electromagnetic interference.

        Therefore, EMC includes two aspects: on the one hand refers to the equipment during normal operation where the environment of the electromagnetic interference can not exceed a certain limit; on the other hand refers to the apparatus present in the environment where electromagnetic interference with certain degree of immunity, namely electromagnetic susceptibility. The so-called electromagnetic interference refers to any device or system performance degradation makes electromagnetic phenomena. The so-called electromagnetic interference is the result of electromagnetic interference caused by equipment or system performance degradation.

       EMC is defined as <device or system in its electromagnetic environment without the normal work environment, any device can not afford anything enough to electromagnetic disturbance ability> EMI (Electro Magnetic Interference) EMI EMC (Electromagnetic Compatibility) electromagnetic compatible EMC = EMI + EMS EMI including conduction, radiation, harmonics, etc.

        Harmonics and flicker should be EMI, not EMS, look 61000-3 family of standards introduced: this section of IEC 1000-3 is concern with the limitation of voltage fluctuations and flicker impressed on the public low-voltage system. Note "impress on" is applied instead of being applied, so the harmonics and flicker are external devices, not the outside of the device, it is EMI, not EMS.