Classification and characteristics of inductors | GETWELL

Classification of inductance

Self inductance device

When an electric current passes through the coil, a magnetic field is created around the coil.When the current in the coil changes, the magnetic field around it also changes accordingly. This change of magnetic field can cause the coil itself to generate induced electromotive force (induced electromotive force) (electromotive force is used to represent the terminal voltage of the ideal power source of the active element). This is self-induction.

An electronic element made by winding a wire and having a certain number of turns and producing a certain self-inductance or mutual inductance, often called an inductance coil.In order to increase the value of inductance, improve the quality factor, reduce the volume, often add iron or magnetic core made of ferromagnetic material.The basic parameters of an inductor include inductance, quality factor, inherent capacitance, stability, current and frequency of use.An inductor composed of a single coil is called a self-inductor, and its self-inductance is also called the self-inductance coefficient.

Transformer

When two inductance coils are close to each other, changes in the magnetic field of one inductance coil will affect the other inductance coil. This effect is mutual inductance.The size of the mutual inductance depends on the degree of coupling between the inductance coil and the two inductance coils.

Characteristics of inductance

The characteristics of an inductor are the opposite of those of a capacitor.The resistance of the dc signal passing through the coil is that the resistance voltage drop of the wire itself is very small.When the ac signal passes through the coil, the two ends of the coil will produce the self-induction electromotive force. The self-induction electromotive force is opposite to the direction of the applied voltage, hindering the passage of the ac. Therefore, the characteristics of the inductor are dc and ac resistance.Inductors often work with capacitors in a circuit to form LC filters, LC oscillators, etc.In addition, people also make use of the characteristics of inductance, manufacturing choke coil, transformer, relay and so on.

Through dc: it means that the inductor has a path close to the dc. If the resistance of the inductor is not considered, the dc can pass through the inductor "unimpeded". For dc, the resistance of the coil itself has very little effect on the resistance of dc, so it is often ignored in the circuit analysis.

Resistance to ac: when ac passes through the inductor coil, the inductor has a blocking effect on ac.