Introduction to electromagnetic wave shielding:
Electromagnetic wave will interact with electronic components and produce interference phenomenon. Electromagnetic wave shielding is to isolate the metal between two space areas to control the induction and radiation of electric field, magnetic field and electromagnetic wave from one area to another.
Schematic diagram of electromagnetic shielding breaking:
Shielding principle of electromagnetic wave
Electromagnetic shielding breaking application:
1) Product test results, frequency beyond the limit of the specified level
2) An error occurred in the grounding treatment, which made the microphone noisy
3) When setting the antenna, enter unnecessary electromagnetic wave
4) Affected by the high frequency of using the machine, the system operates abnormally
5) TV, computer monitor, its external player screen skew phenomenon
6) Making shielding box
7) Wrap all kinds of cables with electromagnetic wave absorbing material
8) Noise occurs on electronic systems such as car audio and navigator
Electromagnetic wave shielding methods and types:
1) Magnetic field shielding
Materials with excellent permeability (permalloy gold foil, silicon steel plate) are used to wrap the source of magnetic field or cover the damaged part, so that the magnetic field can flow to other parts through the surface to solve the problem. It is suitable for transformers and other machines with stronger magnetic field than electric field.
2) Electromagnetic wave shielding
Electromagnetic wave shielding, for example, is almost the same as that when the cabinet is shaken up and down after water is put into it. The method of using all conductive materials (copper foil, aluminum foil, iron plate, etc.) to wrap the cabinet (box) has nothing to do with even a little gap according to the specified value of shielding rate of each product.
Grounding can be divided into signal grounding (below SG) and frame grounding (below FG). The reference potential of DC power supply is also called SG. The best way is to connect SG and FG (ground wire), but the frame size of SG is set according to the intensity of noise, and the thickness of grounding wire connecting SG and FG should also be set. At this time, it is better to set SG frame wider and ground wire thicker.
When electromagnetic wave (noise) is incident on the absorbing body, reflected wave, penetrating wave, passing wave, in which the energy of penetrating electromagnetic wave is transformed into heat, and the effect of eliminating this electromagnetic wave is called absorption. To put it more simply, it is similar to cooking in a microwave oven. When the microwave oven is turned on, electromagnetic wave energy is emitted inside, which transforms the energy into the heat of organism (water) and begins to roll away. It's water that absorbs.
Absorbing material: www.goodsmaterial.com