1. The LC filter, as a passive filter, is a conventional device for compensating DC harmonics, consisting of inductance and capacitance, which can filter out harmonics in the power supply once or more times and clean the DC power supply. 2. The PCB specification is FR4 42X77X1.6MM, with the shortest design for high current circuits and short distances, which can withstand higher currents and minimize external interference. 3. Common mode filtering can solve the problem of fast transient group pulse interference with a repeat frequency of several thousand hertz at specific user locations and play a suppressive role. 4. Description: Introduction to DC filter circuit: The circuit consists of three parts: the first part is a primary LC filter circuit, the second part is a common mode filter, and the third part is a secondary LC filter circuit.