Three, commonly used inductance coil

 

3.1 Single layer coil

   Single-layer coils are wound around a paper tube or bakelite frame with insulated wires. Such as the medium wave antenna coil of a transistor radio.

 

3.2 Honeycomb coil

   If the plane of the coil being wound is not parallel to the rotating surface, but intersects at a certain angle, this kind of coil is called a honeycomb coil. The number of times the wire is bent back and forth after one rotation is often called the number of break points. The advantages of the honeycomb winding method are small size, small distributed capacitance, and large inductance. The honeycomb coils are all wound by the honeycomb winding machine, the more the turning points, the smaller the distributed capacitance

  

 

3.3 Ferrite core and iron powder core coil

   The inductance of the coil is related to the presence or absence of a magnetic core. Inserting a ferrite core in the air-core coil can increase the inductance and improve the quality factor of the coil.

 

3.4 Copper core coil

   Copper core coils are widely used in the ultrashort wave range. The position of the copper core in the coil is used to change the inductance. This adjustment is more convenient and durable.

 

  3.5 Color code inductance coil

   It is a kind of high frequency inductance coil, which is made by winding some enameled wire on the magnetic core and then encapsulating it with epoxy resin or plastic. Its operating frequency is 10KHz to 200MHz, and the inductance is generally between 0.1uH and 3300uH. The color code inductor is an inductor with a fixed inductance, and its inductance marking method is the same as the resistance with a color ring. The unit is uH.

  

 3.6 choke coil (choke coil)

   The coil that restricts the passage of alternating current is called a choke coil, which is divided into a high-frequency choke coil and a low-frequency choke coil.

 

  3.7 Deflection yoke

   The deflection coil is the load of the output stage of the TV's scanning circuit. The deflection coil requires: high deflection sensitivity, uniform magnetic field, high Q value, small size, and low price. . Four, the role of inductance in the circuit

   Basic functions: filtering, oscillation, delay, notch, etc.

   Vivid saying: "pass DC, block AC"

   Detailed explanation: In electronic circuits, the inductance coil acts on the AC current limitation. It can form a high-pass or low-pass filter, phase-shifting circuit and resonant circuit with a resistor or capacitor; the transformer can perform AC coupling, transformation, and transformation. Flow and impedance transformation, etc.

   Knowing from the inductance XL=2πfL, the larger the inductance L and the higher the frequency f, the greater the inductance. The magnitude of the voltage across the inductor is proportional to the inductance L, and it is also proportional to the current change speed △i/△t

   In proportion, this relationship can also be expressed by the following formula: Picture

The inductance coil is also an energy storage element, which stores electric energy in the form of magnetism. The amount of stored electric energy can be expressed by the following formula: WL=1/2 Li2.

   It can be seen that the greater the coil inductance and the greater the flow, the more electric energy stored.

 Symbol of inductance

   Nominal inductance: direct standard, color ring standard, non-standard

   Inductance directionality: no direction

   Check the quality of the inductance: use an inductance measuring instrument to measure its inductance; use a multimeter to measure its on-off, the ideal inductance resistance is very small, almost zero.

 

Fourth, the model, specification and naming of the inductor

   4.1 Chip inductors

   Inductance: 10NH～1MH

   Material: Ferrite, winding type, ceramic laminate

   Accuracy: J=±5% K=±10% M=±20%

   Size: 0402 0603 0805 1008 1206 1210 1812 1008=2.5mm*2.0mm 1210=3.2mm*2.5mm

   Individual schematic diagram:

SMD wire wound inductor

 

Chip multilayer inductor

 

4.2 Power inductor

   Inductance: 1NH～20MH

   With shielding, without shielding

   Size: SMD43, SMD54, SMD73, SMD75, SMD104, SMD105; RH73/RH74/RH104R/RH105R/RH124; CD43/54/73/75/104/105;

 

4.3 Chip beads

   Type: CBG (common type) Impedance: 5Ω～3KΩ

   CBH (large current) Impedance: 30Ω～120Ω

   CBY (peak type) Impedance: 5Ω～2KΩ

   Individual schematic diagram:

SMD beads

 

SMD high current magnetic beads

  picture

   Specifications: 0402/0603/0805/1206/1210/1806 (SMD magnetic beads)

   Specification: SMB302520/SMB403025/SMB853025 (SMD high current magnetic beads)

  

4.4 Plug-in magnetic beads

 

Specification

A

B

C

Impedance value (Ω)

10mHz

100mHz

RH3.5X4.7X0.8

3.5±0.15

4.7±0.3

62±2

20

45

RH3.5X6X0.8

3.5±0.15

6±0.3

62±2

25

65

RH3.5X9X0.08

3.5±0.15

9±0.3

62±2

40

105

 

4.5 Color ring inductance

   Inductance: 0.1uH～22MH

   Size: 0204, 0307, ​​0410, 0512

   Bean-shaped inductor: 0.1uH～22MH

   Size: 0405, 0606, 0607, 0909, 0910

   Accuracy: J=±5% K=±10% M=±20%

   Accuracy: J=±5% K=±10% M=±20%

   

Color ring inductance of the plug-in

 

4.6 Vertical inductor

   Inductance: 0.1uH～3MH

   Specification: PK0455/PK0608/PK0810/PK0912

 

4.7 Axial filter inductor

   Specification: LGC0410/LGC0513/LGC0616/LGC1019

   Inductance: 0.1uH-10mH.

   Rated current: 65mA~10A.

   The Q value is high, the price is generally low, and the self-resonant frequency is high.

   

4.8 Magnetic ring inductance

   Specification: TC3026/TC3726/TC4426/TC5026

   Dimensions (unit mm): 3.25~15.88