In the circle of the circle of the ring is known as the inductance coil is a coil of wire on a circle around the insulation pipe, wire insulation each other, and the insulation pipe can be hollow, can also contain iron core magnetic core. Now these two types of no good who bad, after all, is a very good brand in the electronics industry has been sold. The number of electronic companies in the inductive coil is currently a rising trend, which is not the pursuit of numbness, which also shows that the market is getting more and more attention, and its own value is also being budgeted.