An inductor with a fixed amount of inductance is called a fixed inductor. It can be single-layer coil, multi-layer coil, honeycomb coil and coil with magnetic core, etc. The structure of this kind of coil is based on the inductance and the maximum DC working current. After that, the corresponding diameter of enameled wire would be chosen to be wound on the magnetic core, and then encapsulated with epoxy resin or plastic. The fixed inductor has the advantages of small size, light weight, firm structure, easy installation and so on. It is mainly used in filtering, oscillation, notch and delay circuits.
