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Connector basics.
2018-04-16

The basic structure of the connector.

The basic structural parts of the connector have the contact parts;

Insulator;

The shell (depending on the variety);

(4) in the attachment.

1.

Contacts are the core parts of the connector to complete the electrical connection.

Generally, the positive contact parts and the negative contact parts are made into contact pairs, and the electrical connection is completed through the insertion of the contact parts of the Yin and Yang.

The positive contact is a rigid part, whose shape is a cylindrical (circular pin), a square cylindrical (square pin) or a flat shape (insert).

The positive contact parts are generally made of brass and phosphor bronze.

Negative is jack, it is the key contact for parts, it depends on the elastic structure in elastic deformation with pin inserted timeliness and produce elastic force and positive contact form close contact, complete the connection.

Jack has a variety of structures, a cylinder type (split groove, reducing), a tuning fork type, cantilever type (longitudinal slot), folding type (longitudinal slot, 9 glyph), box (square socket) and hyperboloid line spring socket etc.

2.

insulators Insulators are often referred to as the base (base) or mounting plate (insert), its role is to make contact, in accordance with the need to arrange the location and spacing, and ensure the contact and contact between the parts between the shell and insulation performance.

Good insulation resistance, voltage resistance and easy to process are the basic requirements of insulation materials.

3.

shell Also called shell (shell), is the connector cover, it is installed inside the insulation of the mounting plate and pin to provide mechanical protection, and provide the plug and socket inserted right alignment, then to fix the connector on the device.

4.

Attached is the attached structure attachment and installation attachment.

The structure accessories such as card ring, positioning key, positioning pin, guide pin, connecting ring, cable clip, sealing ring, gasket etc.

Install accessories such as screw, nut, screw, spring coil, etc.

Most of the accessories are standard and general.

Basic performance of the connector.

The basic performance of the connector can be divided into three categories: mechanical performance, electrical performance and environmental performance.

1.

Mechanical properties: in terms of connection function, the insertion force is an important mechanical property.

The insertion force is divided into the insertion force and the pulling force (the pulling force is also called the separation force). The requirements of the two are different.

In the relevant standards have the largest insertion force and the minimum separation force, this suggests that, from the point of use, insert force is smaller (and thus has low insertion force LIF and no insertion force ZIF structure), and if separation force is too small, will affect the reliability of the contact.

Another important mechanical property is the mechanical life of the connector.

Mechanical life is actually a kind of durability index, which is called mechanical operation in GB5095.

It is a loop with one insert and one pull, in order to determine whether the connector can complete its connection function (such as contact resistance value) after the specified plug and pull cycle.

The insertion force and mechanical life of the connector are related to the quality of the coating (sliding friction coefficient) and the precision (alignment) of the contact parts in contact parts.

2.

Electrical properties: the main electrical properties of the connector include contact resistance, insulation resistance and resistance to electrical resistance.

The electrical connector with high quality of contact resistance should have low and stable contact resistance.

The contact resistance of the connector ranges from a few to a few tens of millio.

The insulation resistance measures the insulation performance between the contact parts of the electrical connector and the contact between the contact parts and the shell, and the order of magnitude is hundreds of megaohm to thousands of megaohms.

The strength or voltage withstand voltage or medium pressure is the ability to characterize the rated test voltage between the contact parts of the connector or the contact parts and the enclosure.

(4) other electrical leakage electromagnetic interference attenuation performance evaluation of the connector is electromagnetic interference shielding effect, leakage of electromagnetic interference attenuation is connector electromagnetic interference shielding effect, evaluation is in commonly 100 MHZ ~ 10 GHZ frequency range test.

For rf coaxial connectors, there are electrical indicators such as characteristic impedance, insertion loss, reflectance and VSWR.

Due to the development of digital technology, in order to connect and transmit high speed digital pulse signal, a kind of new type of connector is high speed signal, accordingly, in terms of electrical performance, in addition to the characteristic impedance, also appeared some new electrical indicators, such as crosstalk (crosstalk), transmission delay (delay) and delay skew (), etc.

3.

Environmental performance

Common environmental performance includes temperature resistance, moisture resistance, salt spray, vibration and shock.

The maximum working temperature of the current connector is 200 (with the exception of a few high-temperature special connectors), and the minimum temperature is -65.

As the connector works, the current generates heat at the contact point, resulting in a temperature rise. Therefore, the working temperature is generally considered to be the sum of the ambient temperature and the temperature rise of the contact point.

In some specifications, the maximum temperature rise allowed by the connector in the rated working current is specified.

The intrusion of moisture resistant moisture can affect the insulation performance of the connector and corrode metal parts.

Constant humid heat test conditions for relative humidity of 90% ~ 95% (according to the product specification, up to 98%), temperature + 40 + 20 ℃, the test time according to the provisions of the product for at least 96 hours.

The test of alternating damp and heat is more severe.

(3) resistance to salt fog connector in containing moisture and salt environment work, its processing layer on the surface of the metal structure, contact is likely to produce electrochemical corrosion, affect the physical and electrical properties of the connector.

In order to evaluate the ability of electrical connector to withstand this environment, salt spray test was established.

It is hung connector in steel temperature controlled trials, the provisions of concentration of sodium chloride solution using compressed air, salt fog atmosphere, the exposure time prescribed by the product specification, at least for 48 hours.

(4) vibration and impact resistance to vibration and impact is one of the important performance, electric connector in special application environment, such as aviation and aerospace, railway and highway transportation is particularly important, it is the robustness for testing electric connector mechanical structure and electric contact reliability of important indicators.

There are definite provisions in the relevant test methods.

Peak acceleration, duration and impulse waveform should be specified in the impact test, and the time of electrical continuity interruption.

Electrical connector (5) other environmental performance, according to the requirement of the other environmental performance and sealing (air leak, liquid pressure), liquid impregnation (of certain liquid resistant to bad ability), depression, etc.

Classification and structure of connectors.

Due to the increasing diversity of connectors, new structures and applications are emerging, and attempts to solve classification and naming problems in a fixed pattern have become difficult to adapt.

Nevertheless, some basic categories are still valid.

1.

The interconnection level can be divided into five levels according to the function of the internal and external connection of electronic devices.

The internal connection of the chip package.

The IC encapsulates the connection between pin and PCB.

Typical connector IC socket.

A connection between a printed circuit and a wire or a printed board.

Typical connectors are printed circuit connectors.

The connection between the bottom plate and the bottom plate.

Typical connectors are cabinet connectors.

The connection between the device and the device.

Typical products are round connectors.

There is some overlap between the first and the second levels.

Among the five levels of connectors, the highest market is the first and second level products, and the fastest growing is the product of the first level.

2.

Level of connector specification.

According to the classification of the international electrotechnical commission (IEC), the connector belongs to the electromechanical component of electronic equipment, and its specification level is:

Example: connector.

Sub-family: circular connector.

Type (type) : YB round connector.

Variety (style) : YB3470.

Specification (variant)

3.

In the industry management of our country, the connector and switch and keyboard are collectively referred to as electrical connector, and the electrical connector and relay are called electromechanical components.

4.

Product categories for connectors.

Although there is some confusion about the classification of connector product types, there are only two basic ways to divide the connector product category from a technical point of view:

In shape: circular and rectangular (cross section)

Working frequency: low frequency and high frequency (bounded by 3MHz)

According to the above division, belongs to circular coaxial connectors, printed circuit connector belong to rectangular (historically, printed circuit connector is separated from the rectangular connectors in the singular), and the current popular rectangular connectors its cross section is trapezoidal, similar to the rectangle.

The frequency division between low frequency and high frequency and radio frequency is also basically consistent with 3MHz.

As for other USES, installation method, special structure and special properties can also be divided into many different types, and often appeared in the publication and the manufacturer's literature, but usually only in order to highlight the characteristics and purposes, a basic principle of classification is still not beyond the division of the above.

Considering the technical development and actual situation of the connector, the connector can be divided into the following categories according to its universality and relevant technical standards (sub-categories) :

Low frequency circular connector;

Rectangular connector;

Printed circuit connectors;

Rf connectors;

Optical fiber connector.

5.

The connector model is named.

The connector model name is the basis for customer procurement and manufacturer organization production.

In the domestic and foreign connector industry, the product model name has two kinds of thought: one is to use the letter code and the number method, strive to reflect the main structure characteristic of the product in the model name.

The benefits of this approach are easy to identify, but the arrangement is too long, too complex, and with the miniaturization of the connector, it is difficult to print.

This way, the domestic still popular in some industry standard or national standard and make the rules, such as (connector) printed circuit boards, SJ2297 SJ2298-83-83 (rectangular connector), (ribbon cable connectors), GB9538 SJ2459-84-88 (ribbon cable connectors), etc.

Because of the increasing variety of connector structures, it is increasingly difficult to cover a class of connectors in practice with a naming convention.

Another idea is to use the Arabic numerals.

The benefits of this approach are simple, easy for computer management and small product logo printing.

Major international connector manufacturers are now adopting this approach.

It can be expected that a naming scheme that reflects its own characteristics by the manufacturers will gradually replace the way in which certain naming rules are regulated by the whole industry under the planned economy.

Connector IPxx dustproof and waterproof grade (GB4208-93)
2018-04-16

A list of numbers, and dustproof protection class definition of

0 has no protection or special protection to prevent the invasion of

1 more than 50mm objects 50mm diameter spherical object test may be completely into the shell to prevent

2 spherical objects greater than 12.5mm diameter 12.5mm of the test object intrusion may be completely into the shell to prevent the invasion of

3 is greater than 2.5mm diameter 2.5mm objects the object test shall enter the shell out completely prevent

4 greater than 1.0mm diameter 1.0mm object intrusion object test with

5 dust shall enter the shell is not equal to completely prevent dust from entering into the normal operation, but the amount of dust shall not affect the equipment, shall not affect the safety of

6 dust tight without dust into

two, waterproof rating list number the definition of

0 protection level without protection without special protection
3 Zbr1 vertical direction perpendicular to the direction of water to prevent water should be no harmful effects to prevent

2 when the shell in 15 degrees inclined vertical drop when the vertical surface of the housing in the 15 degree tilt range, vertical drop of water should be no harmful effects of

3 water resistance in the vertical plane in 60 degrees within the scope of water, no harmful effect of

4 water splash to the shell in each direction without harmful effects of

5 anti splash water to the shell in each direction without the harmful effects of

6 to prevent strong water spray to the shell in all directions without strong water harmful effects of

7 to prevent the short time effect of flooding in the provisions of the pressure of the water through the prescribed time after the amount of water does not reach the housing harmful levels of

8 anti continuous immersion effect according to the manufacturers and users agreed conditions (should be more than the number of 7 more severe conditions) continued into the case after immersion in water The amount of water does not reach the harmful degree
I is the dustproof grade, and the P is the water proof grade.
, for example, IP 68 represents the level of protection: dust density, dust free entry and continuous immersion. According to the conditions agreed by the producers and users (the condition is more severe than the number 7), after continuous immersion, the water volume of the case will not reach the harmful level.

Pressure depth conversion table.
2018-04-16

                                                                  压力深度换算表:


BAR

PSI

Kpa

ATM

Depth
(Feet)

Depth
(Meters)

Depth
(Fathoms)

1

15

100

1

33

10

6

2

29

200

2

67

20

11

3

44

300

3

100

31

17

4

58

400

4

134

41

22

5

73

500

5

167

51

28

6

87

600

6

201

61

33

7

102

700

7

234

71

39

8

116

800

8

268

82

45

9

131

900

9

301

92

50

10

145

1000

10

335

102

56

15

218

1500

15

502

153

84

20

290

2000

20

670

204

112

25

363

2500

25

837

255

140

30

435

3000

30

1004

306

167

35

508

3500

35

1217

357

195

40

580

4000

39

1339

408

222

45

653

4500

44

1507

459

251

50

725

5000

49

1674

510

279

100

1450

10000

99

3348

1021

558

150

2175

15000

148

5022

1531

837

200

2901

19999

197

6697

2041

1116

250

3626

24999

247

8371

2551

1395

300

4351

29999

296

10045

3062

1674

350

5076

34999

345

11719

3572

1953

400

5801

39999

395

13393

4082

2232

450

6526

44999

444

15067

4593

2511

500

7252

49999

493

16742

5103

2790

550

7977

54998

543

18416

5613

3069

600

8702

59999

592

20090

6123

3348

650

0427

64998

642

21764

6634

3627

700

10152

69998

691

23438

7144

3906

750

10877

74998

740

25112

7654

4185

800

11603

79998

790

26787

8165

4464

850

12328

84997

839

28461

8675

4743

900

13053

89997

888

30135

9185

5022

950

13778

94997

938

31809

9695

5302

1000

14503

99997

987

33483

10206

5581


Pressure depth conversion relationship.

1 PSI = 0.06895 bar                  1 bar = 14.50326 PSI             1 PSI = 6.8948 KPa

1 PSI =2.306723 ftH2O           1 bar =33.4833 ftH2O