1. Skeleton The skeleton refers to the bracket that winds the coil. Some large fixed inductors or adjustable inductors (such as oscillating coils, chokes, etc.), most of them are wrapped around the skeleton of the enameled wire (or yarn wrapped wire), and then the core or copper core, iron core, etc. Load the inner cavity of the skeleton to increase its inductance. The skeleton is usually made of plastic, bakelite or 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 the enamel wire around the core. Hollow inductors (also known as tire coils or air-core coils, mostly used in high-frequency circuits) do not use magnetic cores, skeletons, and shields. Instead, they are wound on the mold and then removed from the mold. Open a certain distance.
2. Winding Winding refers to a group of coils with defined functions, which are the basic components of an inductor. The windings are divided into single layers and multiple layers. The single-layer winding has two forms of tight winding (one turn of the wire during winding) and inter-winding (each wire is separated by a certain distance between windings); the multilayer winding has layered flat winding and chaos Winding, honeycomb type winding and so on.
3. Magnetic core and magnetic rod core and magnetic rod are generally made of nickel-zinc ferrite (NX series) or manganese-zinc ferrite (MX series). It has “work” shape, column shape, hat shape and “E”. Shapes, cans and other shapes.
4. Iron core The core material mainly includes silicon steel sheet and permalloy, and its shape is mostly “E” type.
5. Shield To prevent the magnetic field generated by some inductors from affecting the normal operation of other circuits and components, a metal screen cover (such as an oscillating coil of a semiconductor radio) is added. Inductors with shields increase the loss of the coil and lower the Q.
6. Packaging Materials After some inductors (such as color code inductors, color ring inductors, etc.) are wound, the coils and cores are sealed with a packaging material. The packaging material is made of plastic or epoxy resin.
Copper coil
The inductance is the ratio of the magnetic flux around the inside of the wire when the alternating current is passed through the wire, and the magnetic flux of the wire is the current that produces the flux. When a direct current is passed through the inductor, only a fixed magnetic line of force is present around the inductor, which does not change with time;
Copper coil
However, when an alternating current is passed through the coil, magnetic lines of force that change over time will appear around it. According to Faraday's law of electromagnetic induction, magnetic generation, the varying magnetic lines produce an induced potential at both ends of the coil, which is equivalent to a "new power supply". When a closed loop is formed, this induced potential generates an induced current. It is known by Lenz's law that the total amount of magnetic lines generated by the induced current is intended to prevent changes in the magnetic lines of force. The change of the magnetic field line is derived from the change of the external alternating current power supply. Therefore, from the objective effect, the inductance coil has the characteristic of preventing the current change in the alternating current circuit. Inductor coils have similar characteristics to the inertia in mechanics. They are electrically named “self-sensing”. Usually, when the knife switch is turned on or the knife switch is turned on, a spark will occur. This self-inductance phenomenon is very Caused by high induced potential.
In short, when the inductor coil is connected to the AC power source, the magnetic lines of force inside the coil will change with the alternating current, causing the coil to generate electromagnetic induction. This electromotive force generated by the change of the current of the coil itself is called "self-induced electromotive force". It can be seen that the inductance is only a parameter related to the number of turns of the coil, the size and shape, and the medium. It is a measure of the inertia of the inductor and is independent of the applied current.
Replacement principle: 1, the inductor coil must be replaced by the original value (the number of turns is equal, the same size). 2. The chip inductors only need to be the same size. They can also be replaced by 0 ohm resistors or wires.
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