Structure of inductance | GETWELL

Inductor is a device that converts electrical energy into magnetic energy and stores it.The structure of the inductor is similar to that of a transformer, but with only one winding.

An inductor has a certain amount of inductance that only impedes changes in the current.If the inductor is in a state where no current passes through it, it will attempt to block the current from flowing through it when the circuit is closed;If the inductor is in the current state, it will attempt to keep the current constant when the circuit is disconnected.

Inductor also known as choke, reactor, dynamic reactor.

Structure of inductance

Inductors are generally composed of skeleton, winding, shield, packaging materials, magnetic core or core.

1. Skeleton generally refers to the support for winding coils.Some of the larger volume of the fixed inductors or adjustable inductors (such as oscillation coil, choke ring, etc.), the majority of the enameled wire (or gauze covered wire) around the skeleton, and then the magnetic core or copper core, iron core, etc. Into the skeleton cavity, in order to improve the amount of inductance.The skeleton is usually made of plastic, bakelite, ceramic, and can be made into different shapes according to actual needs.Small inductors (such as color code inductors) generally do not use a skeleton, but directly wrap enameled wire around the magnetic core.The hollow inductor (also known as the defrosting coil or the hollow coil, mostly used in the high-frequency circuit) does not need the magnetic core, the frame and the shield cover, etc., but first wound on the mold and then take off the mold, and will open a certain distance between the coils.

2.Winding a winding is a set of coils with specified functions. It is the basic component of an inductor.The winding is divided into single layer and multiple layer.The monolayer winding has two forms: dense winding (when winding, the wire goes round by round) and interwinding (when winding, there is a certain distance between the wires in each turn).There are many kinds of multilayer winding such as layering winding, random winding and honeycomb winding.

3, magnetic core and magnetic bar magnetic core and magnetic bar generally adopt nickel zinc ferrite (NX series) or manganese zinc ferrite (MX series) and other materials, it has "gong" shape, column, cap, "E" shape, tank shape and other shapes.

4, the core of iron core materials are mainly silicon steel sheet, permalloy, etc., its shape is mostly "E" type.

5.In order to avoid the influence of magnetic field generated by some inductors on other circuits and components working normally, a metal screen cover (such as the oscillation coil of a semiconductor radio, etc.) is added.Inductor with shield will increase coil loss and reduce Q value.

6, packaging materials some inductors (such as color code inductor, color ring inductor, etc.) after winding, with packaging materials to seal the coil and magnetic core.Packaging materials using plastic or epoxy resin.

Copper coils

Inductance is the ratio of the magnetic flux of a wire to the current producing the alternating magnetic flux generated around the inner part of the wire when an alternating current passes through the wire.When the inductance passes through the dc current, only the fixed magnetic field line around it appears, which does not change with time.

However, when an alternating current is passed through the coil, the magnetic lines of force that change over time appear around it.According to Faraday's law of electromagnetic induction, known as magnetogenesis, the changing magnetic lines of force at either end of the coil generate an inductive potential that ACTS as a "new source".When a closed loop is formed, this induced potential generates an induced current.According to lenz's law, the total amount of magnetic field lines generated by the induced current should be prevented from changing.The change of magnetic field line comes from the change of external alternating power supply, so from the objective effect, the inductance coil has the characteristic of preventing the change of current in the ac circuit.The inductance coil has the similar characteristic with the inertia in the mechanics, in the electricity name "self-induction", usually opens the knife switch or turns on the knife switch moment, will produce the spark, this self-induction phenomenon produces the very high induction potential caused by.

In short, when the inductance coil is connected to the ac power supply, the magnetic field lines inside the coil will always change with the alternating current, causing the coil to generate electromagnetic induction.This electromotive force produced by the change in the coil's own current is called "self-induced electromotive force".Thus, the inductance is only a parameter related to the winding number, size and shape of the coil and the medium. It is a measure of the inertia of the inductor coil and has nothing to do with the impressed current.

Principle of substitution: 1. The inductance coil must be replaced by the original value (the number of turns is equal and the size is the same).2. The SMT inductor only needs to be of the same size and can be substituted by 0 ohm resistance or wire.