LC Filter is a device that filters the interference and signal noise. Actually, the wave is the physical conception. That means the filter of waves. Normally, this conception is widely applied to electronic field. Wave means the changing process that is physical. This changing process is transferred into voltage and electric current. Now, in China, there are many LC filter manufactures, especially, in the south of China. Due to the cheap labor force and best quality, the china LC filters are cross the word.