(中文) 连接器的分类及选型

Definition of connectors
A collective term for a device that connects two or more electrical circuits. As a type of electromechanical component, connectors generally work in pairs and are divided into plugs (male), sockets (female), and English plugs (or male, header); The English word for socket (female) is “Receptacle” or “Socket, Jack, Female”.
It completes the connection and disconnection of electrical appliances through certain mechanical actions, and its main functions include:
● Transmission of signals or electrical energy
● Connect or disconnect the circuit

Classification of connectors
There are many ways to classify connectors, and we will focus on it in this article. However, due to the different application directions of connectors, there are contact and non-contact types. For example, fiber optic connectors and electrical connectors are contact types, while proximity switches are non-contact connectors; There are also classifications of electrical and optical signals. In this article, we mainly discuss contact connectors for electrical signals.
Electronic connectors and their components are important supporting interface components in equipment, scattered throughout various systems and parts of the equipment, responsible for the transmission of signals and energy. The quality of the connection directly affects the safe and reliable operation of the entire system.
Various circuits are composed of interconnected electrical connectors, ranging from high frequency to low frequency, from circular to rectangular, from high current connectors passing through hundreds of amperes to high-density connectors passing through weak signals, from ordinary printed circuit board connectors to fast separation and detachment special connectors. Almost all types of electrical connectors have been widely used in various system engineering, ensuring the normal functioning of equipment integrity.
In summary, on the one hand, facing various types of application scenarios, the classification of industrial connectors is also extremely complex. So with the continuous progress of technology, the use of connectors on the market is also increasing, and the performance of different types of connectors is also greatly different. Manufacturers will use materials with different characteristics to design connectors according to the application environment to ensure stable and reliable use of connectors in different environments.
On the other hand, the reliability of electrical connections directly determines the performance of equipment systems. The performance of electronic connectors is an overall performance evaluation, unlike the terminals of connectors, which can be easily evaluated from material, design, and process aspects.
How to separate connectors
For any molded product, connectors are essential, such as the commonly used USB, headphone jack, Ethernet interface, or military custom interfaces that we rarely see. So, 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 devices, there are six levels of interconnection, as shown in the above figure:
A: Interconnection between components and packaging;
B: Interconnection between packaging and circuit boards;
C: The interconnection between boards;
D: Component to component interconnection;
E: Interconnection between components and input/output interfaces;
F: The interconnection between systems.
2. Classified by transmission signal type:
A: Power connector (for transmitting power);
B: Signal connector (transmitting signals);
C: High frequency connectors (for transmitting data).
3. Classified according to electrical requirements:
A: Universal connectors;
B: High power connectors;
C: High voltage connectors;
D: Pulse connector;
E: Low noise connectors;
F: Phase modulation connector;
G: Precision coaxial connectors.
4. Classified by working frequency:
High frequency connectors, high-frequency coaxial connectors, video connectors, coaxial converters, impedance converters, matching size converters, gender converters, microstrip coaxial converters, waveguide coaxial converters, matched load connectors, low-frequency connectors, printed circuit board connectors, ribbon cable connectors, integrated circuit connectors, mixed connectors, etc
5. Classified by environmental conditions:
A: Sealed connectors;
B: High water pressure sealing connector;
C: High vacuum sealed connectors;
D: Three proof connectors;
E: Radiation resistant connectors;
F: High temperature connectors;
G: Low temperature connectors.
6. Classified by appearance:
Circular connectors, commonly used in military equipment; The main forms of connection include bayonet (quick), thread, automatic locking, push-pull, direct insertion and extraction, etc.
Rectangular connectors have a wide range of applications and are developing rapidly. Many board level connectors belong to the category of rectangular connectors. (There are generally two types of connection methods for plugs and sockets: direct insertion and direct extraction, and threaded locking.)
7. Classified by application direction:
A: RF connectors;
B: Fiber optic connectors;
C: Non contact connectors (such as proximity switches, etc.)
The above classifications are all based on external or application attributes, and they vary from manufacturer to manufacturer. Although NEDA has established classification standards for connector component packaging, with the advancement of technology, connector classification has become more complex. However, in terms of communication connectors, due to the coordination of software protocols, there are indeed few changes that can be effectively distinguished.
A. Multi wire cable connectors, including DB connectors, DIX connectors, and DIN connectors, etc;
B. Twisted pair connectors, including RJ45 and RJ11 connectors;
C. Coaxial cable connectors include T-connectors, BNC connectors, and terminal resistors.
04 Basic Principles for Connector Selection
Current carrying capacity
When selecting a connector for power signal transmission, attention should be paid to the current carrying capacity of the connector, and a reduced rating design should be adopted. At the same time, attention should be paid to the insulation and voltage resistance between the pins.
structure size
The external dimensions of connectors are very important, and there are certain space limitations when connecting in products, especially for connectors on single boards, which cannot interfere with other components. Choose the appropriate installation method based on the usage space and installation location (installation includes front installation and rear installation, and installation and fixation methods include rivets, screws, snap rings, or quick locking of the connector itself) and appearance (straight, curved, T-shaped, circular, square).
impedance matching
Some signals have impedance requirements, especially RF signals, which require more stringent impedance matching. Impedance mismatch can cause signal reflection, thereby affecting signal transmission. There are no special requirements for the impedance of connectors in general signal transmission.
shield
With the development of communication products, EMC is increasingly valued. When selecting connectors, a metal shell is required, and the cable needs to have a shielding layer. The shielding layer should be connected to the metal shell of the connector to achieve shielding effect. Injection molding can also be used to wrap the plug part with copper sheet, and the shielding layer of the cable should be welded together with the copper sheet.
Prevent Misinsertion
There are two aspects to preventing misinsertion: on the one hand, the connector itself, which rotates 180 degrees or is wrongly connected due to misalignment, leads to incorrect signal connection. In this case, it is necessary to choose the anti misinsertion connector as much as possible, or adjust the relative position relationship of the connector to make the assembly unique; On the other hand, in order to reduce the variety of materials, several signals use the same connector. In this case, it is possible to plug the A plug into the B socket. It is important to note that if such a situation occurs, it will cause serious consequences (not a simple alarm, with destructive effects). Therefore, the A and B interfaces must be selected as different types of sockets (such as A being male and B being female).
reliability
The connector is used to connect signals, so the connection part should be reliable (such as surface contact is better than point contact, pinhole type is better than leaf spring type, etc.).
Universality
In the selection process of connectors, it is necessary to choose universal materials as much as possible, especially among products of the same series. The selection of connectors has strong universality, reducing the types of materials, increasing the quantity, reducing costs, and reducing supply risks.
Usage environment
The connector has special requirements when used in outdoor, indoor, high temperature, high humidity, salt spray, mold, cold and other environments.
Insertion and removal frequency
The insertion and removal of connectors have a certain lifespan. After reaching the limit of insertion and removal times, the performance of the connector will decrease. When selecting a connector for some signal interfaces that require frequent insertion and removal, it is important to pay more attention to the insertion and removal times of the connector.
Charged condition
Choose a pin or hole type connector based on whether it is constantly charged or not.
Overall consideration
In the process of selecting connectors, various factors are not independent and often interact with each other. Therefore, we need to comprehensively consider and choose the most suitable connector in the connector selection process. The quality of selection will affect the product to varying degrees at different stages.
05 Frequently Asked Questions
1. How many days is the testing cycle usually?
Answer: Normally, it takes 5-7 days. If urgent testing is required, additional testing fees will be charged.
2. How to confirm the measurement project?
a. Confirm the standards for the test items, including test items, test points, test locations, test image resolution, etc.
b. Confirm the specific content and quantity of the project to be tested.
3. Is there a venue for customers to rectify?
The laboratory has corresponding tools, such as soldering iron, hot air gun, heating table, and other commonly used tools for customers to use. Customers need to prepare their own parts for rectification.