The application of shielding box is very common, but how much do you know about the knowledge of shielding box? According to Xiaobian, the shielding box is made of a conductive silver cloth on foam plastic, forming a soft pad, which takes up most of the loose space, mainly for civilian use, and is suitable for foam liner cabinet and door panel. Today, I would like to give you a good introduction about the precautions of using the shielding box?
1. When the requirements of shielding, ventilation and strength are high but the quality is not strict, the honeycomb plate is used to shield the vent and the wire connection is kept by welding to prevent leakage. When it is not possible to shield the indicator / display from the rear and filter the leads, the front of the indicator / display shall be shielded with a metal mesh or conductive glass connected continuously with the housing. Shield the back of indicator and display as much as possible, and filter all leads with through capacitor.
2. The signal line and control line shall pass through appropriate filter when entering / passing through the enclosure. The multi-core connector with filter pin is suitable for this occasion. Pay attention to the extent to which the overall shielding effectiveness is reduced due to the cable passing through the enclosure. When a typical unfiltered wire passes through the shield, the shielding efficiency is reduced by more than 30 dB.
3. When the power line enters the enclosure, it shall all pass through the filter box. The input end of the filter can go out of the shield housing; if the filter structure is not suitable to go out of the housing, a compartment shall be specially set for the filter when the power line enters the housing. It must be noted that the shielding effectiveness will be seriously reduced when the metal shaft or wire is penetrated in the cut-off waveguide hole. Add metal caps to fuses, sockets, etc.
4. When it is required to use the metal control shaft with insulation to the ground, the short recessive control shaft can be used, and when it is not adjusted, it shall be covered with a nut or a metal pad elastic mounting cap. The metal control shaft passing through the shield shall be grounded with metal contact piece, grounding nut or radio frequency pad. It is also possible to use a circular tube with a cut-off frequency higher than the working frequency of other through waveguides as the control axis instead of a grounded metal axis.
I hope you can pay attention to the points mentioned above.