Definition of Connector
Connect two or more circuit devices collectively. Connector as a mechanical and electrical components, generally work in pairs, divided into plugs (male), sockets (female), plugs in English plup (or male, header); sockets (female) in English Receptanle or Socket, jack, female.
It completes the connection and disconnection of electrical appliances through certain mechanical actions, and its main functions are.
Transmitting signals or transmitting electrical energy
Connect the circuit or cut the circuit
Classification of connectors
Connector classification in many ways, we will focus on this article, but, due to the different directions of connector applications, there are contact and non-contact, such as fiber optic connectors, electrical connectors are contact, proximity switches are non-contact connectors; there are also electrical and optical signal classification. Today we are mainly talking about contact connectors for electrical signals.
Electronic connectors and their components are important supporting interface components in the equipment, scattered in various systems and parts of the equipment, responsible for the transmission of signals and energy. The connection is good or bad, directly related to the safe and reliable operation of the entire system.
Interconnected by electrical connectors form a variety of circuits, from high-frequency to low-frequency, from round to rectangular, from high-current connectors through hundreds of amperes to high-density connectors through weak signals, from ordinary printed board connectors to fast separation off and other special connectors, almost all types of varieties of electrical connectors are used in all types of system engineering have been used in large numbers to ensure the normal functioning of the complete equipment.
In summary, on the one hand, in the face of a variety of different types of application scenarios, the classification of industrial connectors is also extremely diverse and complex. So with the continuous progress of technology, the use of connectors on the market is becoming more and more, the performance of different types of connectors are very different, manufacturers will be based on the application environment to use different characteristics of the material design connectors to ensure that the connector in different environments stable and reliable use.
On the other hand, the reliability of the electrical connection directly determines the performance of the device system. The performance of electronic connectors is the overall performance assessment, unlike the terminals of the connector, which can be easily evaluated in terms of materials, design, and process to assess performance.
Although the variety of connectors today is complex, the choice for performance evaluation is slightly cumbersome, but the benefits of using connectors in equipment are clear:.
1, improve the production process, connectors simplify the assembly process of electronic products, but also simplify the mass production process.
2, easy to maintain, easy to upgrade.
3, to improve design flexibility, the use of connectors so that engineers in the design and integration of new products, as well as components to form a system, there is greater flexibility. Connector end of the number of wires, as well as the spacing of the wires, which make the connection more convenient and fast. It is these small details that can effectively reduce the size of electronic products, while also reducing production costs. It can be effectively used as a data transmission line between mobile motherboards or PCBs.
There are so many connectors, how to divide them?
For any molded product, connectors are essential, such as our common USB, headphone jack, Ethernet interface, or the military custom interfaces we don’t see too often. Therefore, based on a wide range of markets, connector classification is also diverse.
1, according to the function of electronic devices connected inside and outside, the level of interconnection is divided into six types, as shown in the figure above.
A: Component to package interconnection; B: Package to board interconnection; C: Board to board interconnection; D: Component to component interconnection; E: Component to input and output interface interconnection; F: System to system interconnection.
2, according to the type of transmission signal classification.
A: power connectors (transmission of electricity).
B: signal connectors (transmission of signals).
C: high-frequency connectors (transmission of data).
3, according to the classification of electrical requirements.
A: general-purpose connectors.
B: High power connectors.
C: high-voltage connectors.
D: pulse connectors.
E: low-noise connectors.
F: phase-modulation connectors.
G: Precision coaxial connectors.
4、Classified according to working frequency.
High frequency connectors, high frequency coaxial connectors, video connectors, coaxial converters, impedance converters, mating size converters, gender converters, microstrip-coaxial converters, waveguide-coaxial converters, matched load connectors, low frequency connectors, printed board connectors, ribbon cable connectors, integrated circuit connectors, mixed connectors, etc.
5、Classified according to environmental conditions (the above picture is a waterproof connector).
A: Sealed connectors.
B: High water pressure sealed connectors.
C: high-vacuum sealed connectors.
D: triple-proof connectors.
E: irradiation-resistant connectors.
F: High temperature connectors.
G: Low temperature connectors.
6, according to the shape of the classification.
Circular connectors, mostly used in military equipment; (connection form mainly bayonet (fast), threaded, automatic latching, push-pull, straight plug and pull, etc.) rectangular connectors, widely used, the rapid development of many board-level connectors are rectangular connectors. (The plug and socket connection is generally straight plug and pull and thread locking two forms.)
7、Classification according to the application direction.
A: RF connectors.
B: fiber optic connectors.
C: non-contact connectors (such as proximity switches, etc.)
The above classification are in accordance with the external or application attributes to classify, specifically to the individual manufacturers will begin to vary, although the NEDA developed a connector component package classification level standards, however, with the progress of technology, connector classification and began to be complex. However, in terms of communication connectors, because of the software protocol with, indeed less and can effectively distinguish.
A, multi-wire cable connectors, including DB connectors and DIX connectors and DIN connectors, etc.
B, twisted pair connectors, including RJ45 and RJ11 connectors.
C, coaxial cable connectors including T connectors and BNC connectors and termination resistors.
Basic principles of connector selection
Load capacity
In the selection of the power signal connector when the connector is more concerned about the load capacity, to use the derating design, while paying attention to the insulation voltage between the pins.
Structure size
Connector size is very important, the connection in the product are certain space limitations, especially the single board connector, can not interfere with other components. According to the use of space, installation parts to choose the appropriate installation method (installation with front and rear installation, installation fixed rivet, screw, card ring or connector itself card pin fast locking, etc.) and shape (straight, curved, T-shaped, round, square).
Impedance matching
Some signals have impedance requirements, especially RF signals, impedance matching requirements are more stringent, impedance mismatch will cause signal reflection, thus affecting the signal transmission. General signal transmission on the impedance of the connector does not have special requirements.
Shielding
With the development of communication products, EMC is being paid more and more attention to the choice of connectors when the need for a metal shell, while the cable needs to have a shielding layer, the shielding layer should be connected to the metal shell of the connector to achieve the shielding effect, you can also use injection molding method, the plug parts with copper skin wrapped, the cable shielding layer and copper skin welded together.
Anti-misplug
There are two aspects of anti-misplug: on the one hand, the connector itself, the connector itself rotated 180 degrees, misalignment of the wrong connection leads to signal misconnection, at this time need to pay attention to the choice of anti-misplug connector as far as possible, or by adjusting the relative position of the connector relationship to make the assembly unique; on the other hand, for the sake of reducing the type of material considerations, several signals are used the same connector, then there may be A plug into the B socket On the other hand, in order to reduce the variety of materials, several signals are using the same connector, then it may appear that the A plug into the B socket, it is necessary to pay attention to, if such a situation will cause serious consequences (not simple alarm, with destructive), the A and B interface must be selected as different types of socket (for example, A for male, B for female).
Reliability
Connectors are used to connect signals, so the connection parts should be reliable (e.g. face contact is better than point contact, pinhole type is better than leaf spring type, etc.).
Universality
In the selection process of connectors to choose as common materials, especially between the same series of products, the choice of connectors with a strong commonality, reduce the types of materials, increase the number of costs, while reducing the risk of supply.
Use environment
Connectors used outdoors, indoors, high temperature, high humidity, salt spray, mold, cold and other environments, the connectors have special requirements.
Plugging frequency
Connector plugging and unplugging have a certain life span, plugging and unplugging the number of times to reach the limit, the connector performance will decline, some signal interfaces need to plug and unplug often when the choice of connectors should pay more attention to the number of times the connector plugged and unplugged.
Charged situation
According to the often charged or not, choose a pin-type or hole-type connector.
Comprehensive consideration
In the process of selecting the connector, the various factors are not independent of each other, often interact, so we have to consider the connector selection process to choose the most appropriate connector, the choice of good or bad at different stages will affect the product to varying degrees.
