What is a connector?

2022-07-18
What is a connector?

What is a connector?

Connectors, CONNECTOR, are also known as connectors, plugs and sockets in the industry. Generally refers to electrical connectors. That is, a device that connects two active devices to transmit current or signals.

Connector is a component that we electronic engineers often come into contact with. Its role is very simple: in the circuit is blocked or isolated between the circuit, bridging the communication, so that the current flow, so that the circuit to achieve the intended function. Connector is an indispensable part of the electronic equipment, along the current flow path, you will always find one or more connectors. Connector form and structure is ever-changing, with the application object, frequency, power, application environment, etc., there are different forms of connectors. For example, the connector used to light the lights on the field and the connector of the hard disk drive, and the connector of the ignition rocket is very different. But no matter what kind of connector, it is important to ensure the smooth continuous and reliable flow of current. In terms of generalization, the connector is connected not only to the current, in today's rapid development of optoelectronics technology, fiber optic systems, the carrier of the transmission signal is light, glass and plastic instead of ordinary circuits in the wire, but the optical signal path is also used in the connector, they serve the same purpose as the circuit connector.Since we are only concerned with circuit connectors, this course will focus on circuit connectors and their applications in close conjunction with Molex products.

 

Why use connectors?

Imagine what it would be like if there were no connectors. For example, if an electronic device is to be connected to a power supply, the two ends of the connecting wires must be fixed to the electronic device and the power supply by some method (e.g. soldering). In this way, both for the production and use, have brought a lot of inconvenience. Take a car battery as an example. Assuming that the battery cable is welded to the battery, the car manufacturer adds work to the installation of the battery, increasing production time and costs. Battery damage needs to be replaced, but also to send the car to the repair station, desoldering to remove the old, and then welded on the new, to pay more labor costs for this. With the connector can eliminate a lot of trouble, buy a new battery from the store, disconnect the connector, remove the old battery, install the new battery, reconnect the connector can be. This simple example illustrates the benefits of connectors. It makes the design and production process easier and more flexible, reducing production and maintenance costs.

Benefits of connectors:
 
  1. Improve the production process
Connector simplifies the assembly process of electronic products. Also simplifies the process of mass production.
 
  1. Easy maintenance
If an electronic component failure, equipped with a connector can quickly replace the failed components.
 
  1. easy to upgrade
with technological advances, equipped with connectors can update the components, with new and better components to replace the old;
 
  1. Improve the flexibility of design
The use of connectors gives engineers greater flexibility when designing and integrating new products and when composing systems with components.
 

Basic performance of connectors

Connector knowledge of the basic performance of the connector can be divided into three main categories: namely, mechanical performance, electrical performance and environmental performance. Another important mechanical performance is the mechanical life of the connector. Mechanical life is actually a durability (durability) indicators, in the national standard GB5095 called it mechanical operation. It is inserted once and pulled out as a cycle, to the specified plugging cycle after the connector can normally complete its connection function (such as contact resistance value) as the basis for judging.

 

mechanical properties on the connection function, plugging force is an important mechanical properties.

The insertion force is divided into insertion force and extraction force (extraction force is also called separation force), and the requirements of the two are different. In the relevant standards there is a maximum insertion force and minimum separation force provisions, which indicates that, from the point of view of use, the insertion force to be small (thus having a low insertion force LIF and no insertion force ZIF structure), and separation force if too small, it will affect the reliability of the contact. Connector insertion and removal force and mechanical life with the contact structure (positive pressure size) contact parts plating quality (coefficient of sliding friction) and the contact arrangement size accuracy (alignment) related.
 

Electrical properties of the connector's main electrical properties include contact resistance, insulation resistance and electrical strength.

① Contact resistance of high-quality electrical connectors should have a low and stable contact resistance. Contact resistance of the connector from a few milliohms to tens of milliohms ranging.
② insulation resistance to measure the electrical connector contact between the parts and between the contact parts and shell insulation performance indicators, the order of magnitude of hundreds of megohms to thousands of megohms ranging.
③ electrical strength or voltage resistance, dielectric withstand voltage, is a characterization of the connector between the contact parts or between the contact parts and the shell to withstand the rated test voltage capacity.
④ Other electrical properties.
EMI leakage attenuation is to evaluate the connector EMI shielding effect, EMI leakage attenuation is to evaluate the connector EMI shielding effect, generally tested in the frequency range of 100MHz ~ 10GHz.
For RF coaxial connectors, there are also electrical indicators such as characteristic impedance, insertion loss, reflection coefficient, voltage standing wave ratio (VSWR). Due to the development of digital technology, in order to connect and transmit high-speed digital pulse signals, a new class of connectors that high-speed signal connectors, accordingly, in terms of electrical performance, in addition to the characteristic impedance, there are some new electrical indicators, such as crosstalk (crosstalk), transmission delay (delay), time lag (skew), etc..


 

Common environmental properties include resistance to temperature, humidity, salt spray, vibration and shock.

① Temperature resistance of the current connector's maximum operating temperature of 200 ℃ (except for a few high-temperature special connectors), the minimum temperature of -65 ℃. As the connector work, the current at the contact point to generate heat, resulting in temperature rise, so it is generally believed that the working temperature should be equal to the ambient temperature and contact temperature rise and the sum. In some specifications, the connector is clearly specified in the rated operating current to allow the maximum temperature rise.
② resistance to moisture moisture intrusion will affect the connection h insulation performance, and rust metal parts. Constant damp heat test conditions for relative humidity 90% to 95% (according to product specifications, up to 98%), temperature +40 ± 20 ℃, the test time according to product regulations, at least 96 hours. Alternating heat and humidity test is more stringent.
③ salt spray resistant connectors in an environment containing moisture and salt work, its metal structural parts, contact parts surface treatment layer may produce galvanic corrosion, affecting the physical and electrical properties of the connector. In order to evaluate the ability of the electrical connector to withstand this environment, the salt spray test is specified. It is the connector suspended in a temperature-controlled test chamber, with a prescribed concentration of sodium chloride solution sprayed with compressed air to form a salt spray atmosphere, the exposure time specified by the product specification, at least 48 hours.
④ Vibration and shock resistance to vibration and shock is an important performance of electrical connectors, in special application environments such as aviation and aerospace, rail and road transport is particularly important, it is an important indicator to test the robustness of the mechanical structure of the electrical connector and electrical contact reliability. There are clear provisions in the relevant test methods. Shock test should be specified in the peak acceleration, duration and shock pulse waveform, as well as the time of electrical continuity interruption.
⑤ other environmental performance according to the use of the requirements of the electrical connector's other environmental performance are sealing (air leakage, liquid pressure), liquid impregnation (the ability to withstand the vices of a particular liquid), low air pressure, etc.
 

Connector categories and definitions

Due to the increasing diversity of connectors and the emergence of new structures and applications, attempts to solve the classification and naming problem with a fixed model have become difficult to adapt. Nevertheless, some basic classifications are still valid.
 

1. Levels of interconnection


According to the function of the internal and external connection of electronic devices, interconnection can be divided into five levels.
① The internal connection of the chip package
② The connection of the IC package pins to the PCB. Typical connector IC socket.
③ printed circuit and the connection of the wire or printed board. Typical connectors are printed circuit connectors.
④ Base board to base board connection. Typical connectors are cabinet connectors.
⑤ Device to device connection. Typical products are circular connectors.
Levels (iii) and (iv) have some overlap. Of the five levels of connectors, the highest market volumes are for products in levels ③ and ⑤, and the fastest growing products are currently in level ③.
 

2. The level of connector specifications.


According to the International Electrotechnical Commission (IEC) classification, the connector belongs to the electronic equipment with electromechanical components, the specification level for.
Category (family) example: connectors
Sub-division (sub-family) example: circular connectors
Type (type) example: YB type circular connectors
Species (style) example: YB3470
Specifications (variant)
 

3. The connector product categories.


Connector product type is divided into some confusion, but from a technical point of view, the connector product category only two basic divisions: ① according to the shape of the structure: round and rectangular (cross-section), ② according to the operating frequency: low frequency and high frequency (to 3MHz as the boundary).

According to the above division, coaxial connectors belong to the circular, printed circuit connectors belong to the rectangular (historically, printed circuit connectors are indeed separated from the rectangular connectors into a class of their own), and the current popular rectangular connectors whose cross-section is trapezoidal, close to the rectangular. To 3MHz as the boundary to divide the low and high frequencies and radio waves are also basically the same frequency division.

As for other uses, installation methods, special structures, special performance, etc. can also be divided into many different types, and often appear in publications and manufacturer's promotional materials, but generally just to highlight a feature and use, the basic classification is still not beyond the above principles of classification.

Considering the technical development of connectors and the actual situation, from its generality and related technical standards, connectors can be divided into the following categories (subcategories): ① low frequency circular connectors; ② rectangular connectors; ③ printed circuit connectors; ④ RF connectors; ⑤ fiber optic connectors.

 

4. The connector model naming.


Connector model naming is the basis for customer procurement and manufacturer production organization. In the connector industry at home and abroad, there are two ideas for product model naming: one is to use the letter code plus the number approach, and strive to reflect the main structural characteristics of the product in the model naming. The advantage of this approach is easy to identify, but the arrangement is too long and too complex, with the miniaturization of the connector to bring a lot of difficulties in printing. Currently in some industry standards and even national standards to make provisions, such as SJ2298-83 (printed circuit connector), SJ2297-83 (rectangular connector), SJ2459-84 (ribbon cable connector), GB9538-88 (ribbon cable connector), etc.. Due to the increasing diversity of connector structure, in practice with a naming rule to cover a class of connectors is increasingly difficult. Another way of thinking is to use a combination of Arabic numerals. This approach has the advantage of simplicity, easy computer management and small product logo printing. The major international connector manufacturers are currently using this approach. Can be expected to be developed by the manufacturers to reflect their own characteristics of the naming scheme will gradually replace the planned economic system by the entire industry to specify a unified approach to naming rules.

5 Connector market development overview

With the rapid growth of consumer electronics, automotive electronics, communications terminal market and the global connector production capacity continues to shift to Asia and China, Asia has become the connector market has the most potential for development, while China will become the fastest growing and largest capacity of the global connector market. It is estimated that the future growth of the Chinese connector market will continue to outpace the global average, the next five years, the average annual growth rate of China's connector market size will reach 15%, and by 2010, China's connector market capacity will reach 25.7 billion yuan.Olink Technology Co., Ltd. has 15 years of professional experience in wire harness manufacturing, and has strong supply capabilities in a variety of connector development.

The main supporting areas of electrical connectors are transportation, communications, networks, IT, medical, home appliances, etc., supporting the rapid development of the technical level of the product and its rapid market growth, a strong pull on the development of connector technology. So far, the connector has developed into a full range of products, a rich variety of specifications, a variety of structural types, professional direction subdivision, industry features are obvious, the standard system standardized series and specialized products.


Overall, the development of connector technology presents the following characteristics: high-speed signal transmission and digitalization, integration of various types of signal transmission, miniaturization of product size miniaturization, low-cost products, contact termination method table paste, modular combination, plugging and unplugging convenience and so on. The above technologies represent the development direction of connector technology, but it should be noted that: the above technologies are not all connectors are necessary, different supporting areas and different use of the environment of the connector, the demand for the above technologies are completely different points.

6 The development direction of the connector

Connector development should be miniaturized, high density, high-speed transmission, high-frequency direction. Miniaturization refers to the connector center spacing is smaller, high density is to achieve a large number of cores. High-density PCB (printed circuit board) connector effective total contact pieces up to 600 cores, special devices up to 5000 cores. High-speed transmission refers to modern computers, information technology and networking technology requires signal transmission time scale rate up to the megahertz band, pulse time to reach sub-milliseconds, therefore requiring high-speed transmission connectors. High-frequency is to adapt to the development of millimeter-wave technology, RF coaxial connectors have entered the millimeter-wave operating frequency band.

7 domestic and foreign well-known connector manufacturers
AVIC Optoelectronics, aerospace appliances, Sichuan Huafeng, Foxconn Technology, Tyco Electronics, Molex, Amphenol, FCI, JAE, connector common terms
1. connector: usually mounted on the cable or equipment for the transmission line system electrically connected separable components (except for adapters)
2. RF connectors: are used in the RF range of connectors. 3.
3. video: radio waves in the frequency range between 3HZ ∽ 30MHZ.
4. RF: radio waves in the frequency range between 3 thousand HZ ∽ 3000GHZ.
5. high frequency: frequency range between 3MHZ ∽ 30MHZ radio waves. 6.
6. coaxial: the inner conductor has a dielectric support, the structure can be used in the measurement of the frequency range to get the minimum internal reflection coefficient.
7. tri-coaxial: transmission line consisting of three concentric conductors with a common axis and insulated from each other.
8. grade: the level of mechanical and electrical precision of the connector, especially in terms of the specified reflection coefficient.
9. General purpose connectors (Class 2): A connector manufactured with the widest allowable dimensional deviation (tolerance), but still ensuring a minimum of specified performance and intermatchability.
Note: The requirements of the reflection coefficient may or may not be specified.
10. High-performance connectors (Class 1): by the frequency change to specify the limit value of the reflection coefficient of a connector, usually the specified dimensional tolerances are not stricter than the corresponding Class 2 connectors, but the need to ensure that the connector meets the requirements of the reflection coefficient, the manufacturer has the responsibility to choose a tighter tolerance.
11. Standard test connector (Class 0): a specific type of precision manufactured connector used to measure the reflection coefficient of Class 1 and Class 2 connectors, the error caused by the measurement results can be negligible.
Note: Standard test connectors are usually part of different types of adapters, and adapters and precision connector connections form part of the test equipment.
12. Sealing
12.1 Sealed connectors: connectors with the ability to meet the specified gas, moisture or liquid sealing requirements.
12.2 barrier seal: to prevent and gas, moisture or liquid along the axial into the connector shell inside the seal.
12.3 Panel Seal: A seal that prevents gas, moisture, or liquid from entering between the fixed or adapter housing and the panel through the mounting holes.
Note: Seals are usually supplied as stand-alone products.
12.4 Plug face seal: A seal that prevents gas, moisture, or liquid from entering the interface between a pair of plug-in connectors.
12.5 Gas seal: A seal that meets the requirements of test Qk in IEC 60068-2-17 "Basic Environmental Test Procedure Part 2: Test - Test Q: Seal".
The basic structure of the connector composition
The basic structural components of the connector ① contact parts; ② insulator; ③ shell (depending on the species); ④ accessories.
1 contact parts (contacts) is the core parts of the connector to complete the electrical connection function. Generally by the positive contact parts and the negative contact parts to form a contact pair, through the Yin and Yang contact parts of the plug to complete the electrical connection.
Positive contact is a rigid part, its shape is cylindrical (round pin), square column (square pin) or flat (insert). Positive contact parts are generally made of brass, phosphor bronze.
The negative contact is the jack, is the key parts of the contact pair, it relies on the elastic structure in the insertion of the pin when the elastic deformation and elastic force with the positive contact to form a close contact, complete the connection. Jack structure of many kinds, there are cylindrical (split groove, indentation), tuning fork, cantilever beam type (longitudinal slotted), folded type (longitudinal slotted, 9-letter), box-shaped (square jack) and hyperbolic line spring jack, etc..
2 insulator insulator is also often called the base (base) or mounting plate (insert), its role is to make the contact parts according to the required location and spacing arrangement, and to ensure that the insulation properties between the contact parts and between the contact parts and the shell. Good insulation resistance, voltage resistance and easy processing is the choice of insulation materials processed into the basic requirements of the insulator.
3 Shell, also known as the shell (shell), is the outer cover of the connector, which provides mechanical protection for the insulated mounting plate and pins inside, and provides alignment when the plug and socket are inserted, and thus the connector is fixed to the equipment.
4. Accessories Accessories are divided into structural accessories and mounting accessories. Structural accessories such as snap rings, positioning keys, positioning pins, guide pins, coupling rings, cable clamps, seals, gaskets, etc.. Mounting accessories such as screws, nuts, screws, spring rings, etc.. Most of the accessories have standard parts and common parts.

Introduction to the structural principle of the connector

The basic structural components of the connector are ① contact parts; ② insulator; ③ shell (depending on the variety); ④ accessories.
Contact parts (contacts) is the core parts of the connector to complete the electrical connection function. Generally by the positive contact parts and the negative contact parts of the contact pair, through the Yin and Yang contact parts of the plug to complete the electrical connection.
Positive contact is a rigid part, its shape is cylindrical (round pin), square column (square pin) or flat (insert). Positive contact parts are generally made of brass, phosphor bronze].

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2. Insulator Insulator is also often called the base (base) or mounting plate (insert), its role is to make the contact parts according to the required location and spacing arrangement, and to ensure that the insulation between the contact parts and between the contact parts and the shell performance. Good insulation resistance, voltage resistance and easy processing is the choice of insulation materials processed into the basic requirements of the insulator.
3 Shell, also known as the shell (shell), is the outer cover of the connector, which provides mechanical protection for the insulated mounting plate and pins inside, and provides alignment when the plug and socket are inserted, and thus the connector is fixed to the equipment.
4 Accessories Accessories are divided into structural accessories and mounting accessories. Structural accessories such as snap rings, positioning keys, positioning pins, guide pins, coupling rings, cable clamps, seals, gaskets, etc.. Mounting accessories such as screws, nuts, screws, spring rings, etc.. Most of the accessories have standard and common parts. Connector, connector technology, electronic connector, connector wire, connector plug, terminal, cable harness, switch, wire and cable, fiber optic connector, computer connector, connector , line cable, card holder, wire harness, jst, HDMI, USB, molex, AMP, terminal, wiring terminal, FPC, Shenzhen, switch, pin, RF coaxial connector, FFC, cell phone connector, connector
 

The basic performance of the connector

The basic performance of the connector can be divided into three categories: namely, mechanical performance, electrical performance and environmental performance.
1. mechanical performance on the connection function, plugging force is an important mechanical performance. Insertion force is divided into insertion force and pull-out force (pull-out force is also known as separation force), the requirements of the two are different. In the relevant standards have a maximum insertion force and minimum separation force provisions, which indicates that, from the point of view of use, the insertion force to be small (so that there is a low insertion force LIF and no insertion force ZIF structure), while the separation force is too small, it will affect the reliability of the contact.
Another important mechanical property is the mechanical life of the connector. Mechanical life is actually a durability (durability) indicators, in the national standard GB5095 to call it mechanical operation. It is inserted once and pulled out as a cycle, in the specified plugging cycle after the connector can normally complete its connection function (such as contact resistance value) as the basis for judging.
Connector insertion and removal force and mechanical life of the contact structure (positive pressure size) contact parts plating quality (coefficient of sliding friction) and the size of the contact arrangement accuracy (alignment) related.
2. Electrical performance
Field Application Engineer
Job Define just completed after collecting and synthesizing by ourselves
1. Collect and analyze the current status information of customers (production and R&D) - and feedback the corresponding information to Sales&RD, and develop the product Spec internally with reference to customer standards;
2. Assist Sales to do new product introduction briefing to customers (including external transfer products), sales have the intention to send samples and send samples to FAE related information should be informed in advance;
3. Assist and define QA on product ORT verification and analysis;
4. Pay attention to and collect market information, complete analysis and feedback with company management and RD & Sales to do relevant R&D trends and product introduction evaluation;
5. Support CQS to solve technical problems related to products from clients;
6. Complete analysis of competitors' products collected by CQS & Sales for internal reference (need to keep sample and complete report);

Finally attached, an article on how to choose automotive connectors. For details, you can click here. “how to select the right connector for you