It completes the connection and disconnection of electrical appliances through certain mechanical actions. Its main functions are:
1.Transmitting signals or transmitting electrical energy
2.Make or break a circuit
There are many ways to classify connectors, which we will focus on in this article. However, due to the different application directions of connectors, there are contact and non-contact types. For example, optical fiber connectors and electrical connectors are contact types, and proximity switches are non-contact connectors. There are also classifications of electrical and optical signals. 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 quality of the connection is directly related to the safe and reliable operation of the entire system.
Various circuits are interconnected by electrical connectors, from high frequency to low frequency, from circular to rectangular, from high-current connectors passing hundreds of amperes to high-density connectors passing weak signals, from ordinary printed board connectors. Almost all types of electrical connectors have been widely used in various system engineering, from special connectors such as quick separation and detachment, to ensure the normal performance of the complete functions of the equipment.
To sum up, on the one hand, in the face of various types of application scenarios, the classification of industrial connectors is extremely complicated. Therefore, with the continuous advancement of technology, more and more connectors are used on the market, and the performance of different types of connectors is also very different. Manufacturers will use materials with different characteristics to design connectors according to the application environment. Ensure the stable and reliable use of the connector in different environments.
On the other hand, the reliability of the electrical connection directly determines the performance of the equipment system. The performance of electronic connectors is an overall performance evaluation. Unlike the connector terminals, the performance can be easily evaluated from the aspects of material, design, and process.
Although there are many types of connectors today, and the selection is a little troublesome for performance evaluation, the benefits of using connectors in equipment are obvious:
1. Improve the production process, the connector simplifies the assembly process of electronic products, and also simplifies the mass production process;
2. Easy to maintain and upgrade;
3. Improve the flexibility of design. The use of connectors enables engineers to have greater flexibility when designing and integrating new products and when composing systems with components. The number of wires at the connector end and the spacing of the wires make the connection more convenient and faster. It is these small details that can effectively reduce the volume of electronic products, and at the same time reduce production costs. It can be effectively used as a data line for transmission between moving main boards or between PCBs.
There are so many connectors, how to divide them?
For any molded product, connectors are essential, such as our commonly used USB, headphone jack, Ethernet interface, or our less common military custom interface. Therefore, based on a wide range of markets, connector classifications are also diverse.
1. According to the functions of the internal and external connections of electronic equipment, the interconnection levels are divided into 6 types:
A: Interconnection of components to packages;
B: The interconnection of the package to the circuit board;
C: board-to-board interconnection;
D: component-to-component interconnection;
E: Interconnection of components to input and output interfaces;
F: System-to-system interconnection.
2. Classification according to the type of transmission signal:
A: Power connector (transmitting power);
B: signal connector (transmission signal);
C: High frequency connector (transmitting data).
3. Classification according to electrical requirements:
A: Universal connector;
B: high power connector;
C: high voltage connector;
D: pulse connector;
E: low noise connector;
F: phase modulation connector;
G: Precision coaxial connector.
4. Classification 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, Matching Load connectors, low frequency connectors, printed board connectors, ribbon cable connectors, integrated circuit connectors, mixed connectors, etc.
5. Classification according to environmental conditions:
A: sealed connector;
B: High water pressure seal connector;
C: high vacuum sealed connector;
D: Three-proof connector;
E: Radiation resistant connector;
F: high temperature connector;
G: Cryogenic connector.
6. Classification according to appearance:
Circular connectors are mostly used in military equipment; (connection forms mainly include bayonet (fast), thread, automatic locking, push-pull, in-line and straight-out, etc.) rectangular connectors are widely used and develop rapidly. Many board-level connectors are It is a rectangular connector. (There are generally two types of connection methods for plugs and sockets: straight plug and straight plug and screw lock.)
7. Classification according to application direction:
A: RF connector;
B: fiber optic connector;
C: Non-contact connector (such as proximity switch, etc.)
The above classifications are all based on external or application attributes, and each manufacturer is different. Although NEDA has formulated a classification standard for connector component packaging, with the advancement of technology, connector classification has become more complicated. However, in terms of communication connectors, due to the cooperation of software protocols, there are indeed few changes and effective distinctions.
A. Multi-wire cable connectors, including DB connectors, DIX connectors and DIN connectors.
B. Twisted pair connectors, including RJ45 and RJ11 connectors;
C. Coaxial cable connectors include T connectors, BNC connectors and terminal resistors.
Basic principles of connector selection
When choosing a connector for power supply signals, pay more attention to the current carrying capacity of the connector. A derating design should be adopted, and at the same time, attention should be paid to the insulation withstand voltage between the pins.
The external dimensions of the connector are very important, and the connection in the product has certain space restrictions, especially the connector on the single board, which cannot interfere with other components. Choose the appropriate installation method according to the use space and installation location (there are front installation and rear installation, and the installation and fixing methods include rivets, screws, collars or fast locking of the bayonet of the connector itself, etc.) and shape (straight, curved, T type, round, square).
Some signals have impedance requirements, especially radio frequency signals, which have stricter requirements on impedance matching. When the impedance does not match, it will cause signal reflection, which will affect signal transmission. Generally, signal transmission has no special requirements on the impedance of the connector.
With the development of communication products, EMC is getting more and more attention. The selected connector needs to have a metal shell. At the same time, the cable needs to have a shielding layer. The shielding layer should be connected with the metal shell of the connector to achieve the shielding effect. Using injection molding method, the plug part is wrapped with copper skin, and the shielding layer of the cable is welded with the copper skin.
There are two aspects to anti-mis-insertion: one is the connector itself, the connector itself rotates 180 degrees, misalignment and wrong connection lead to wrong signal connection, at this time, it is necessary to pay attention to choosing the anti-mis-insertion connector as much as possible, or by adjusting the relative position of the connector Make the assembly unique; on the other hand, in order to reduce the types of materials, several signals use the same connector. At this time, it may appear that the A plug is inserted into the B socket. At this time, attention should be paid. If this happens When it will cause serious consequences (not a simple alarm, but destructive), the A and B interfaces must be selected as different types of sockets (for example, A is male, B is female).
Connectors are used to connect signals, so the connection parts should be reliable (for example, surface contact is better than point contact, pinhole type is better than leaf spring type, etc.).
In the selection process of connectors, common materials should be selected as much as possible, especially among products of the same series, the selection of connectors has strong versatility, reducing material types, increasing quantities and reducing costs, while reducing supply risks.
When the connector is used in outdoor, indoor, high temperature, high humidity, salt spray, mold, cold and other environments, there are special requirements for the connector.
The plugging and unplugging of the connector has a certain life. After the number of plugging and unplugging reaches the limit, the performance of the connector will decrease. When some signal interfaces need to be plugged and unplugged frequently, it is necessary to pay more attention to the number of plugging and unplugging of the connector when choosing a connector.
According to whether it is always live or not, choose a pin type or a female type connector.
In the process of selecting a connector, various factors are not independent and often interact with each other. Therefore, we must consider comprehensively in the process of connector selection to choose the most suitable connector. The quality of the selection will be different at different stages. degree of influence on the product.