The difference is that EMC is a comprehensive offensive and defensive capabilities, EMI is the attack, EMS is the defense;
The connection is that EMC = EMI + EMS.
Difference in detail:
EMC (ElectroMagnetic Compatibility) - - Meaning:
Directly translated as "Electromagnetic Compatibility". EMC (ElectroMagneticCompatibility) - Comprehensive offense and defense capabilities
Meaning:
Directly translated as "Electromagnetic Compatibility".
It refers to the ability of electronic equipment to generate electromagnetic energy that neither interferes with other electronic equipment nor is interfered with by electromagnetic energy from other electronic equipment.
EMC includes EMI and EMS requirements:
On the one hand, electronic equipment in the normal operation of the process of electromagnetic interference in the environment can not exceed a certain limit, that is, EMI; on the other hand, electronic equipment in the environment where the presence of electromagnetic interference has a certain degree of anti-jamming ability, that is, EMS.
Specific explanations
Specifically in the EMC testing of electronic equipment, the relevant standards specify the maximum value of EMI, as well as the minimum value of EMS, as if to limit the "attack" at a lower level, the "defense" required at a higher level. This is also very understandable, just like we have a watchdog, you do not want it to take the initiative to run out of the door to bite people, but you require it to carry the enemy when they come to offend.
EMI (ElectroMagneticInterference) - Attack
Meaning:
The direct translation is "Electromagnetic Interference".
It is a phenomenon in which an electronic device (the source of the interference) interferes with other electronic devices through electromagnetic waves.
Example:
When we watch TV, next to someone using a hairdryer or electric razor and other household appliances, the TV screen will appear on the snowflake noise; rice cooker cooking rice; turned off the air conditioning will start on its own? These are common electromagnetic interference phenomenon. More seriously, if the electromagnetic interference signal obstructs the medical electronic equipment that is monitoring the condition or the airplane that is flying, it will cause unimaginable consequences. From these examples, it is as if the electronic equipment has an invisible "attack power", the normal operation of other electronic equipment caused by the disruption and destruction.
From the "attack" mode:
EMI has two main types: conduction interference and radiation interference. Electromagnetic conduction interference refers to the interference source through the conductive medium (such as wires) to their own electrical network on the signal coupling (interference) to another electrical network. The most common example is the power supply in our computers will have an impact on the electrical network at home, in the computer at the same time as the computer may be dimmed lights at home, which is more obvious in the use of miscellaneous low-quality power supply computer performance. In the internal structure of today's power supplies, one or two EMI filtering circuits are essential, where "EMI" is aimed at electromagnetic interference to prevent the power supply from working too much on the outside world.
EMS (ElectroMagneticSusceptibility) - defensemeaning:
Translated as "electromagnetic sensitivity".
It refers to the ease with which an electronic device can degrade its own performance due to the electromagnetic energy it receives from the outside world.
Example:
For example, if the same hairdryer or shaver interferes with a TV, some TVs have snowflakes and noise on the screen, while others are fine. This shows that in the case of electromagnetic interference "attack", the former electromagnetic sensitivity is higher, more likely to be injured, that is, "defense" is low; and the latter electromagnetic sensitivity is lower, less likely to be injured, that is, "defense" is higher. The latter is less sensitive and less likely to be injured, i.e., the "defense" is higher.
Contact details:Because there is EMI, there is EMC, because the EMS standard, in order to realize the EMC.
That is, EMC = EMI + EMS
Three elements of electromagnetic interference: theoretical and practical research has shown that, regardless of the complexity of the system or a simple device, the occurrence of any one of the electromagnetic interference
must have three basic conditions: first of all, there should be a source of harassment; secondly, there is a way to spread the interference energy and channel; thirdly, there must be
the response of the object being interfered with. In the theory of electromagnetic compatibility in the interference object collectively referred to as sensitive equipment (or sensitive device). Therefore, electromagnetic interference
disturbance source, harassment propagation path (or transmission channel) and sensitive equipment called electromagnetic interference three elements.