The inductance coil is composed of a circle by a wire around the wire insulation pipe insulation, each other, and the insulating tube can be hollow, can also contain iron core or cores, referred to as the inductor.
The inductance coil and capacitor electrical properties on the contrary, "resistance of high frequency, low pass". That is the low frequency signal can be easily through it. The inductance coil DC resistance to almost zero. The performance index is the main inductance coil size. In addition, the guide wire wound inductor generally has some resistance, the resistance is very small, can be neglected. This small resistance when the current through the coil in some circuits in cannot be ignored, because of the great will power consumption in the coil coil, the coil heat and even burn, so some time to consider electric power coil can bear

In the circuit inductance coil commonly used classification there are so few: in accordance with the core using the inductance coil material, has the core inductance coil, inductance coil copper, hollow inductance coil and so on