1. Single layer coil

　　Single-layer coils are wound around a paper tube or bakelite skeleton with insulated wires. Such as the medium wave antenna coil of a transistor radio.

　　2, honeycomb coil

　　If the coil is wound, its plane is not parallel to the rotating surface, but intersects at a certain angle, this kind of coil is called a honeycomb coil. The number of times the wire is bent back and forth after one rotation is often called the number of bending points. The advantages of the honeycomb winding method are small size, small distributed capacitance, and large inductance. The honeycomb coils are all wound by the honeycomb winding machine, the more the turning points, the smaller the distributed capacitance

　　3, ferrite core and iron powder core coil

　　The inductance of the coil is related to the presence or absence of a magnetic core. Inserting the ferrite core in the air-cored coil can increase the inductance and improve the quality factor of the coil.

　　4, copper core coil

　　 Copper core coils are widely used in the ultra-short wave range. The position of the copper core in the coil is used to change the inductance. This adjustment is more convenient and durable.

　　5, color code inductor

　　 Color code inductors are inductors with a fixed inductance. The inductance marking method is the same as the resistance with a color ring.

　　6, choke coil (choke coil)

　　The coil that restricts the passage of alternating current is called a choke, which is divided into high-frequency choke and low-frequency choke.

　　7, deflection coil

　　 The deflection coil is the load of the TV's scanning circuit output stage. The deflection coil requires: high deflection sensitivity, uniform magnetic field, high Q value, small size, and low price.