The inductor coil is generally composed of a core or a core, a skeleton, a winding group, a shield cover, an encapsulating material, and the like.
1. 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 which are wrapped around the enamel wire (or yarn wrapped wire) directly on the skeleton, and then the core or copper core, iron core Wait for 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 I-inductors) generally do not use a skeleton, but directly wrap the enameled wire around the core.
Hollow inductors (also known as tire coils or air-core coils, which are mostly used in high-frequency circuits) do not use cores, skeletons, shields, etc., but are wound on the mold before removing the mold and pulling the coils between the coils. Open a certain distance.
2. Winding refers to a group of coils with defined functions, which are the basic components of an inductive coil.
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. Cores and magnetic rod cores and magnetic rods are generally made of nickel-zinc ferrite (NX series) or manganese-zinc ferrite (MX series). They have a "work" shape, a column shape, a hat shape, and an "E" shape. A variety of shapes such as cans, rings, and the like.
4. The core material mainly includes silicon steel sheet, permalloy, etc., and its shape is mostly "E" type.
5. The shield is added to the metal screen cover (such as the oscillation coil of the semiconductor radio, etc.) in order to prevent the magnetic field generated by some of the inductors from affecting the normal operation of other circuits and components. Inductors with shields increase the loss of the coil and lower the Q.
6. 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.
(2) Small fixed inductors
Small fixed inductors are usually wound directly on the core by enameled wire. They are mainly used in circuits such as filtering, oscillation, notching, and delay. They are available in both sealed and unsealed packages. There are two shapes of vertical and horizontal.
1. Vertical sealed fixed inductors Vertical sealed fixed inductors use the same-direction pins, domestically produced series of inductors such as LG and LG2, the inductance range is 0.1~2200μH (straight standard on the housing), rated working current is 0.05 ~1.6A, the error range is ±5%~±10%. Imported TDK series color code inductors, the inductance of which is marked on the surface of the inductor with color points.
2. Horizontal sealed fixed inductors Horizontal sealed fixed inductors adopt axial type pins, and domestically produced series of LG1, LGA, LGX, etc.
The inductance of LG1 series inductors ranges from 0.1 to 22000μH (straight to the housing), the rated operating current is 0.05~1.6A, and the error range is ±5%~±10%.
The LGA series inductors are ultra-small and similar in appearance to 1/2W color ring resistors. The inductance ranges from 0.22 to 100μH (marked on the housing with a color ring) and the rated current is 0.09~0.4A.
LGX series color code inductors are also small package structure, the inductance range is 0.1~10000μH, and the passenger current is divided into four specifications: 50mA, 150mA, 300mA and 1.6A.
(3) Adjustable inductor
Commonly used adjustable inductors include an oscillating coil for a semiconductor radio, a line oscillating coil for a television, a linear coil, an intermediate frequency trap coil, a frequency compensation coil for sound, and a wave blocking coil.