The way that interference enters the device is nothing more than three different ways: electromagnetic coupling, capacitive coupling and direct entry.
When a wire passes through a magnetic field, or when a magnetic field is close to a wire, there will be electromagnetic coupling, and an electromotive force is induced on the wire. This is the transformer effect. Therefore, when an external magnetic field is close to the computer, it may introduce noise interference into the computer.
Capacitive coupling is another cause of noise interference. When two objects are close to each other, the capacitive reactance existing between the two objects can form a conductive path, thereby affecting the inherent conductivity of the two. If the voltage difference between the two reaches a very high level and the distance is very close, it may even produce a discharge between the two objects, forming a voltage transient.
Noise interference directly enters the electrical equipment, which is the most common interference entry method. No more explanation is needed. No matter which method enters the equipment interference, as long as it enters the system, it can be in the system arbitrarily. Spread.
The first effect that noise interference may have on the device is the error in the working state of the device, and you may pay a high price for this. For example, under the effect of noise interference, a CNC machining machine may drill a wrong hole in a wrong position, and as a result, a workpiece worth tens of thousands of yuan will be scrapped.
The second direct impact that noise interference may cause is to cause hardware damage to the device. For example, in a switching power supply, instant lightning interference may damage the rectifier diode. Even if it passes the rectifier part by chance, because the ordinary electrolytic capacitor has a poor smoothing effect on high-frequency interference, it may continue to invade the low-voltage part, and finally enter the control part of the device, the remaining consequences will be self-evident.
