Inductor is an element that converts electrical energy into magnetic energy and stores it. The inductor has only one winding, and the inductor has a certain inductance, which can hinder the change of current. If there is current passing, the inductor will try to hinder the change of current when it is disconnected. Inductors are also called chokes and reactors. The structure of the inductor is similar to that of a transformer, but it has only one winding.

Inductance is a component that is often seen in electronic circuits. The induction cooker we use for cooking has a coil disk which is a special inductor, power transformers, current transformers, and chokes are all inductors. It generally plays many roles in the circuit, such as filtering, choking, tuning, delay, coupling, compensation, and so on. Let's talk about how the inductor is charged and discharged.

Inductors are generally composed of a skeleton, windings, shields, packaging materials, magnetic cores or iron cores.

Function

locking AC and DC, blocking high-frequency and low-frequency (filtering), which means that high-frequency signals will encounter a lot of resistance when passing through the inductance coil, and it is difficult to pass, while the resistance presented by low-frequency signals when passing through it is It is relatively small, that is, low-frequency signals can pass through it easily. The resistance of the inductor to direct current is almost zero.

Classification of inductors

Self-inductor When current flows through the coil, a magnetic field will be generated around the coil. When the current in the coil changes, the surrounding magnetic field also changes accordingly. This changing 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 supply for active components). It's self-induction.

It is an electronic component that is wound with a wire and has a certain number of turns, which can produce a certain amount of self-inductance or mutual inductance. It is often called an inductance coil. In order to increase the inductance value, improve the quality factor, and reduce the volume, iron cores or magnetic cores made of ferromagnetic materials are often added. The basic parameters of inductors include inductance, quality factor, inherent capacitance, stability, current passing and frequency of use, etc. The inductor composed of a single coil is called a self-inductor, and its self-inductance is also called the self-inductance coefficient.

When the two inductance coils of the transformer are close to each other, the change of the magnetic field of one inductance coil will affect the other inductance coil, and this effect is mutual inductance. The magnitude of the mutual inductance depends on the degree of coupling between the self-inductance of the inductor coil and the two inductor coils. The components made using this principle are called mutual inductors.

characteristic

The characteristics of inductors are contrary to those of capacitors, and they have the characteristics of blocking the flow of AC and DC. The resistance when a DC signal passes through the inductor is that the resistance of the wire itself is very small. When an AC signal passes through the self-inductor, a self-induced electromotive force will be generated at both ends of the coil, and the direction of the self-induced electromotive force is opposite to the direction of the voltage, which hinders the passage of AC. In addition, the higher the frequency of the AC signal, the greater the coil impedance. Inductors often form LC filters, LC oscillators, etc. together with capacitors. People also use the characteristics of inductance to manufacture choke coils, transformers, relays, etc.

Unit inductance symbol: L

Inductance units: Hen (H), millihenry (mH), microhenry (μH), the conversion relationship is: 1H=10^3mH=10^6μH=10^9nH.