EMI FILTER Module

Functional
power EMI filter is a reactive low-pass filter installed in the power supply inlet of electronic equipment, which can inhibit the noise interference transmitted through the power line of the power grid. It can also inhibit the high-frequency interference signals generated by the electronic devices themselves from entering the power grid and harming other electronic devices. Therefore, EMI has become a device that must be installed in electronic equipment.
Power supply noise is a type of electromagnetic interference. The frequency spectrum of conducted noise is approximately 10 kHz to 30 MHz and can be up to 150 MHz. According to the different propagation directions, power supply noise can be divided into two categories: one is the external interference introduced from the incoming power line, and the other is the noise generated by the electronic device and conducted through the power line. This indicates that the noise is a two-way interference signal, and the electronic device is both an object of noise interference and a noise source. If we look at the characteristics of formation, noise interference is divided into two types: interference in series mode and common mode interference. Series-mode interference is noise between two power lines (referred to as line-to-line). Common-mode interference is the noise of two power lines to ground (abbreviated as line-to-ground). Therefore, the electromagnetic interference filter should meet the requirements of electromagnetic compatibility (EMC) and it must also be a two-way RF filter. On the one hand, it must filter out the external electromagnetic interference introduced from the AC power line, and on the other hand, it can avoid the Noise is emitted from outside to avoid affecting the normal operation of other electronic devices under the same electromagnetic environment. In addition, the electromagnetic interference filter can suppress the serial mode and common mode interference.

Cautions
The selection of EMI filter should take into account its operating voltage, operating current, and withstand voltage.
EMI filter should be installed at the entrance of the power supply to reduce radiation interference.
EMI filter cable is better than double wire, it can eliminate some high frequency interference signals.
EMI filter input and output lines should not be parallel, need to pull a certain distance to ensure the function of the filter.
The E point of the EMI filtermust be in good contact with the chassis shell, and connect the grounding wire.

The connection mode:
L is the live line of AC 220V AC and
N is the neutral line AC220V AC.
E is the output common (equivalent to GND) to the chassis.