Inductance coil Working principle of electromagnetic induction. When current flows through the wire, it will have an impact in certain electromagnetic conductors and magnet wire, and electromagnetic field lines within the sensing range. The electromagnetic field generated by the wire, the role itself has called "self", that is, to change their line current generates a magnetic field produce changes further affect the magnetic field of the current in the wire; cookers function in other conductors produced called " transformer".

Resistors, capacitors and inductors, current signal flowing in the circuit they will be a certain degree of resistance, the resistance which we call "impedance" put forward by the current signal inductor coil inductance coil inductance used. Sometimes we call it the "sense" or "coil" by the letter "L". Inductor coil turns wound we call it "turns.

In contrast with the electrical characteristics of a capacitor inductance coil, "high-frequency resistance, a low-pass." That is, the high-frequency signal through the inductor coil will encounter strong resistance, it is difficult through; and existing low-frequency signal, the resistance is small, that is, the low-frequency signals can easily pass it. Inductor DC resistance is almost zero.