There are currently tens of thousands of types of electronic connectors, and the number of models exceeds one million. It is difficult to find a connector that meets your needs. Therefore, in order to better distinguish connectors in the industry, the National Electrical Distributors Association (NEDA), supported by many companies, defines the industry level of connectors and divides them into 5 industry levels, namely:
1. Wire-to-board connector or wire-to-wire connector
2. Box-to-box or input/output level
3. IC chip or chip to package level
4. IC package or board-level package
5. PCB board-to-board connector
This is the association's classification of connectors. In fact, there is no definite classification of connectors, but they can be roughly summarized into the above five categories. With the development of products, there are many classification methods. According to the frequency, it can be divided into low-frequency and high-frequency connectors; according to its appearance characteristics, it can be divided into round, rectangular, and flat cable connectors; according to the application occasions, it can be divided into printed circuit board connectors, integrated block plugs and sockets, headphone and earplug plugs and sockets, power plugs and sockets, etc. Common connectors on the market at present are
1. Circular connector/aviation connector
Circular connector is also called aviation connector. It has a standard spiral locking mechanism, and the number of contact points ranges from two to hundreds. It is used for electrical connections between circuit boards or complete equipment that do not need to be plugged and unplugged frequently. Threaded connections have certain reliability and the best quality-strength ratio in harsh environments, so circular connectors have been widely used between circuits, between cables, and between cables and panels.
2. Rectangular connector
Rectangular arrangement can make full use of spatial position and is widely used for interconnection within the machine. When equipped with a shell locking device, it can be used for connection between cables and panels outside the machine.
3. Wire Terminal
Strip flat cable connectors are made of dozens of wires with polyvinyl chloride as the insulation layer bonded together side by side. It takes up little space, is light and flexible, is easy to wire, and is not easy to confuse. The plug of the ribbon cable is the connector at both ends of the cable. It does not need to be welded to connect to the cable, but relies on pressure to make the blade on the connection end pierce the insulation layer of the cable to achieve electrical connection. Its process is simple and reliable, and the socket part of the cable is directly welded on the printed circuit board. Ribbon flat cable connectors are often used in low voltage and low current situations, suitable for the connection of weak signals, and are mostly used in computers and external devices.
4. Printed circuit board connector
In order to facilitate the replacement and maintenance of printed circuit boards, this connector is often used for interconnection between printed circuit boards or between printed circuit boards and other components. According to its structural form, it is divided into reed type and pinhole type. The base of the sheet socket is pressed with high-strength phenolic plastic, and there is an elastic metal sheet in the hole. This structure is relatively simple and easy to use. The pinhole type can be divided into single-row and double-row types. The socket can be directly welded on the printed circuit board. The number of leads can range from two to one hundred. It is often used for external connection of printed circuit boards in small instruments.
5. Automotive connectors
In order to meet the personalized high-standard requirements of high integration, high-standard anti-electric shock protection, arc protection, high protection standards, high stability, and whether the weight strength of the connector material is easy to process, etc., automotive connectors are formed.
After determining the classification of the connector, you can look for it according to the electrical properties and electrical parameters of the connector. The main purpose of the connector is to transfer electrical signals from one place to another, playing the role of bridging the circuit. The electrical parameters of the connector usually refer to the rated voltage, rated current, contact resistance between the terminals, insulation resistance of the connector itself, insulation dielectric strength, etc. of the connector. These parameters directly affect the material selection of the connector. For example, in high-voltage situations, the connector must use an insulator material with strong insulation performance
Signal integrity When there is coupling (inductance or capacitance) between different signal lines, crosstalk occurs, which affects the overall signal integrity of the circuit. Especially in high-speed data transmission systems such as data centers, crosstalk between multiple signals on the backplane is a major problem that cannot be ignored. Although crosstalk will be avoided as much as possible during the PCB layout process, if the connector is not selected properly, all the efforts in the early stage will be wasted.
In summary, how to find a connector that meets your requirements
1. Get the classification category of the connector based on product requirements
2. Determine the properties of the connector based on electrical performance and electrical properties
3. Determine whether the selected connector will not interfere with the signal based on the components around the connector
