Inductance (inductance) is one of the properties of electronic circuit or device, refers to: when the current changes, the resistance change due to electromagnetic induction electromotive force (EMF, electromotive force). Any current in the circuit, can produce a magnetic field, the magnetic flux of the magnetic field ACTS on the circuit. According to lenz's law, the magnetic flux can borrow by induction voltage (bemf) and tend to resist changes in current. Flux change value of the ratio of current change quantity called self-induction, self-induction is usually referred to as directly is the inductance of the circuit. With inductive device called the inductor (inductor, Chinese in general are also referred to as inductance), inductor, which is generally a coil, can be assembled magnetic field. (self-induction is a special case of the mutual inductance) basic function: the function of the circuit inductance filter, oscillation and delay, trap image: \"dc, ac resistance dc:\" the so-called dc is refers to, in a dc inductance is equivalent to the effect of a wire, no effect. Communication: resistance in ac circuits, the inductance impedance, namely the XL, the whole circuit the current will be smaller, there is a certain inhibition on communication. Detailed explanation: in the electronic circuit, inductance coils for communication limited flow effect, it has to do with a resistor or capacitor can be high or low pass filter, phase shift circuit and resonant circuit, etc.; The change of the role of the inductance is a current, but this effect and resistance current circulation role there is a difference between. Resistance current circulation role in electric consumption as its logo, and inductance hinder the change of current is pure current change, are not allowed to hinder inductance current increases when the current is added, when the current reduced inductance hinder the decrease of the current. Inductance hinder the current change process does not consume electricity, it will hinder the current increase of electric energy in the magnetic field in the form of stored temporarily, when current decrease hours it will be the release of the magnetic field energy, in the result, is hampering the current changes.