Ignition coil is mainly composed of the core, the winding, bakelite covers, cups, etc; (1) insulated from each other by a core of silicon steel strip stacked from the system, inter-chip oil or coated with an oxidation insulation apartheid, the outer insulating jacket sleeve, whose role is to enhance the flux. (2) the primary winding wire with a wire diameter of 0.5 ~ 1.0mm stratification in the primary winding around the outer layer to facilitate heat dissipation, the primary winding 230 to 370 turns. Outside package also several layers of insulation paper, in order to enhance the insulation. After winding around the vacuum immersed in a mixture of paraffin wax and rosin, further reinforced insulation. The role of the primary winding in the winding current is to use electromagnetic induction to achieve change. (3) secondary winding with a wire diameter of 0.06 ~ 0.10mm enameled wire around the core insulation on the external casing, about 11,000 to 26,000 turns. To strengthen the insulation and protection from mechanical damage, each wire are separated by an insulating paper, the outermost layers of insulating paper more or put cardboard sleeve. Function of generating an electromotive force mutual inductance. (4) steel sleeve fitted with magnetic steel sleeve between the primary winding and the housing. With magnetic steel sheet rolled into a cylindrical shape, form part of the magnetic circuit, the iron core is formed semi-closed magnetic circuit to reduce magnetic flux leakage. (5) To enhance filler insulation and prevent moisture ingress, filled asphalt or transformer oil within the housing when oil filled transformer coil better heat dissipation, low temperature, and good insulation. In recent years the use of sulfur hexafluoride (SF6) and other gas-insulated or insulated plastic molding. (6) additional resistance three-fit the ignition column housing provided with an additional external resistance, additional resistance is connected to both ends of bakelite cover "+ switch" and "switch" next column, its role is to improve the ignition performance. Two next column ignition coil without additional resistance in the ignition switch and the ignition coil "+" next column room, connected to an additional resistance line.