The basic function of coil inductance in circuit filtering, oscillation, delay, notch, etc

Image: "DC, AC"

Through direct current: the so-called through direct current means that in the direct current circuit, the role of the inductor is equivalent to a wire, without any role.

AC resistance: in AC circuit, the inductor will have impedance, that is, XL, the current of the whole circuit will be reduced, which has a certain blocking effect on AC.

Elaboration: in the electronic circuit, the inductance coil acts on the AC finite current, and it and the resistor or capacitor can form a high-pass or low-pass filter, phase-shifting circuit and resonant circuit, etc.

The role of the coil inductor is to prevent the current from changing, but this role is different from that of the resistance to prevent the current from flowing.

Resistance to block current flow is the consumption of electric energy as its symbol, and the change of inductance to block current is simply not to let the current change, when the current increases the inductance to block the current increase, when the current decreases the inductance to block the current decrease.

Inductance does not consume electrical energy. It temporarily stores the electrical energy in the form of a magnetic field when the current increases. When the current decreases, it also releases the energy of the magnetic field and, in effect, prevents the current from changing.