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The difference between EMI, EMS, and EMC, engineers must read!

Edit: GCDC  Affiliation: Technical Information  Views: 79  Release time: 2022-12-19

The electromagnetic radiation problem of electronic products has attracted more and more attention. I believe that most people are familiar with the term EMC (Electromagnetic Compatibility). However, similar professional terms such as EMI and EMS often appear in front of everyone. They It seems that they are all related to radiation protection (electromagnetic radiation), which makes people confused. So, what are the similarities and differences between them?

EMI—Attack Power
The literal translation of EMI (Electro Magnetic Interference) is "electromagnetic interference", which refers to the phenomenon that electronic equipment (interference source) interferes with other electronic equipment through electromagnetic waves. For example, when we watch TV, someone next to us uses a hair dryer or an electric razor, and there will be snowflake noise on the TV screen; the rice cooker will not cook the rice well; the air conditioner will start by itself when it is turned off... These are common electromagnetic interference phenomena. What's more, if the electromagnetic interference signal interferes with the medical electronic equipment that is monitoring the disease or the aircraft in flight, it will cause disastrous consequences. Judging from these examples, it seems that electronic equipment has invisible "attack power", causing disruption and damage to the normal operation of other electronic equipment.

Where there is a spear, there is a shield, and where there is electromagnetic interference, there is anti-electromagnetic interference. Please name our second protagonist EMS below. The literal translation of EMS (Electro Magnetic Susceptibility) is "Electromagnetic Susceptibility", which refers to the ease with which the performance of electronic equipment degrades due to external electromagnetic energy. For example, due to the same interference from hair dryers or electric shavers, snow noise appears on the screen of some TVs, but some TVs are safe and sound. This shows that in the case of being "attacked" by electromagnetic interference, the former has higher electromagnetic sensitivity and is more vulnerable to injury, that is, lower "defense power"; while the latter has lower electromagnetic sensitivity and is less likely to be injured, that is, "defense power" higher.

EMC—comprehensive offensive and defensive capabilities
With the spear and the shield, we finally use them to arm our third protagonist, EMC.
The literal translation of EMC (Electro Magnetic Compatibility) is "electromagnetic compatibility", which refers to the ability of the electromagnetic energy generated by electronic equipment to neither interfere with other electronic equipment nor interfere with the electromagnetic energy of other electronic equipment. Therefore, EMC includes two requirements: EMI and EMS: on the one hand, it is required that the electromagnetic interference generated by electronic equipment in the environment during normal operation should not exceed a certain limit, that is, EMI; The electromagnetic interference that exists has a certain degree of anti-interference ability, that is, EMS.

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