Today we mainly talk about the main steps of making an inductor. Before designing, select the type of magnetic material and select a reasonable core model. On this basis, design a reasonable air gap length and coil structure, including calculating the number of turns, selecting the wire. Therefore, the magnetic material of the magnetic core must be determined first. The magnetic core material should have high permeability, low coercivity and high resistivity. Commonly used magnetic materials include silicon steel, ferrite, amorphous alloy, ultrafine crystal, precision alloy, magnetic powder core, etc. Secondly, select the core type and determine the core structure. The selection of wires is also very important, such as power frequency inductors, the coils are made of round copper wires or thin copper tapes, for inductors operating at medium and high frequencies, in order to reduce eddy current losses, wire bundles should be selected. The last is the calculation of temperature rise.