In more complex instruments and equipment, connectors are often used for connection. This "building block" structure not only guarantees the quality of mass production of products, reduces the cost of the system, and provides convenience for debugging and maintenance. When the equipment fails, the maintenance personnel do not have to check the component level (that is, check the cause of the failure and trace the source to the specific component. This work takes a lot of time), as long as it is judged which board is abnormal. It can be replaced immediately, troubleshooting in a short time, shortening downtime, and improving equipment utilization. The replaced circuit board can be repaired within ample time and used as a spare part after repair.

　　1, printed circuit board socket

　　In more complicated instruments and equipment, this connection method is often used. This method is to make a printed plug from the edge of the PCB printed board, and the plug part is designed according to the size of the socket, the number of contacts, the distance of the contacts, the location of the positioning hole, etc., to match the special PCB printed board socket.

　　When making the board, the plug part needs to be gold-plated to improve the wear resistance and reduce the contact resistance. This method is simple to assemble, has good interchangeability and maintenance performance, and is suitable for standardized mass production. The disadvantage is that the cost of the printed board is increased, and the manufacturing precision and process requirements of the printed board are higher; the reliability is slightly worse, and the contact is often poor due to the oxidation of the plug part or the aging of the socket spring. In order to improve the reliability of external connections, the same lead wire is often led out in parallel through the contacts on the same side or on both sides of the circuit board.

　　PCB printed board socket connection method is often used in products with multi-board structure. The socket and the printed board or the bottom plate have two types: spring type and pin type.

　　2, standard pin connection

　　This method can be used for the external connection of printed boards, especially in small instruments, which often use pin connections. Connect the two printed boards through standard pins. The two printed boards are generally parallel or vertical, which is easy to achieve mass production.