1, single layer coil The single-layer coil is wound around the paper tube or bakelite skeleton in a circle with insulated wires. Such as a transistor radio wave antenna coil. 2, honeycomb coil If the coil is wound, its plane is not parallel to the plane of rotation, but intersects at an angle. This type of coil is called a honeycomb coil. And the number of times the wire is bent back and forth, often referred to as the number of vertices. The advantage of the honeycomb type winding method is that the volume is small, the distributed capacitance is small, and the inductance is large. The honeycomb coils are wound by the honeycomb winding machine. The more the folding 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 a ferrite core into the air core coil increases the inductance and improves the quality of the coil. 4, copper core coil Copper core coils are used in the ultrashort wave range. The position of the copper core in the coil is used to change the inductance. This adjustment is convenient and durable. 5, color code inductor A color code inductor is an inductor with a fixed inductance, and its inductance sign method is marked with a color ring like a resistor. 6, choke (choke) The coil that restricts the passage of alternating current is called a choke, and is divided into a high frequency choke coil and a low frequency choke coil. 7, deflection coil The deflection yoke is the load of the output stage of the television scanning circuit. The deflection yoke requires: high deflection sensitivity, uniform magnetic field, high Q value, small size and low price.