EMI电源滤波器起到两个低通滤波器的作用:一个是衰减共模干扰，另一个是衰减差模干扰。 EMI电源滤波器能在阻带范围内衰减射频能量，而让工频无衰减，或者很少的衰减，就能通过EMI电源滤波器。 EMI电源滤波器是电子设备设计工程师控制传导电磁干扰和辐射电磁干扰的首选工具。(The EMI power filter plays the role of two low pass filters: one is to attenuate the common mode interference and the other is to attenuate the differential mode interference. The EMI power filter can attenuate radio frequency energy in the range of stopband, and make the power frequency without attenuation, or little attenuation, can pass the EMI power filter. The EMI power filter is the preferred tool for electronic device design engineers to control the transmission of electromagnetic interference and radiation electromagnetic interference.)