Precautions for magnetic locks

Modern science and technology cannot be separated from electrical and electronic equipment or systems. These electrical and electronic equipment or systems are very sensitive to electromagnetic interference in the surroundings when they are working. On the other hand, they themselves will send electromagnetic interference signals to the surroundings, affecting the normal operation of other electrical and electronic equipment or systems. These phenomena are common even in daily life. For example, the combustion system of a nearby car will cause the TV image to jump and produce a popping sound; turning on or off the power switch will make the radio make a "pop" sound; using a flashlight or electric welding machine will cause the computer to work abnormally or even be damaged.

All electromagnetic phenomena (voltage, current or electromagnetic field) that are undesirable for electrical and electronic equipment (systems) are collectively referred to as electromagnetic interference (EMI) or electromagnetic noise. In fact, electromagnetic interference exists in the environment where we live and work, but when their impact is relatively small, it has not attracted enough attention. At present, electronic equipment and systems that are particularly sensitive to electromagnetic interference have been widely used, so the problem of electromagnetic interference has increasingly attracted serious attention. People have been working hard on electromagnetic interference control (EMIc) to deal with the problem of electromagnetic interference in electrical and electronic systems1-1, which led to the concept of electromagnetic compatibility.

The so-called electromagnetic compatibility (EMC)1 includes two meanings: (1) the coordination between electronic systems or equipment in the electromagnetic field environment; (2) the normal operation of electronic systems or electronic equipment in the electromagnetic environment. That is to say, when designing an electronic system or equipment, on the one hand, it must be ensured that it can operate normally according to the design requirements in the electromagnetic environment, and on the other hand, it must also control the electromagnetic noise it emits so that it does not affect the normal operation of other systems or equipment. We call equipment and systems that meet these requirements electromagnetically compatible.