Inductors in the circuit mainly play the role of filtering, oscillation, delay, notch and so on, but also screen signal, filter noise, stable current and restrain electromagnetic interference and so on.
Inductance is an electronic component that converts electrical energy into magnetic energy. The value of inductance indicates the current's ability to generate a magnetic field. With the same current, the coil is wound into a multi-turn coil, which can increase the magnetic field. At the same time, magnetic materials such as iron chips are added to the coil, which can greatly improve the magnetic field. Therefore, iron ferrite cores or magnetic rings(NiZn,MnZn,Nano) are generally used in the coil.(Frequency from 1khz-500mhz)