Electronic components and electromechanical components have electrical contacts. The electrical connections between two discrete contacts are called interconnections. Electronic equipment must be interconnected in accordance with the circuit diagram to achieve the intended function.
As a part of the whole machine, a printed circuit board can not form an electronic product, and there must be the problem of external connection. Electrical connections are required between printed boards, printed circuit boards and off board components, printed boards and equipment panels. The selection of the best combination of reliability, manufacturability and economy is one of the important contents of printed circuit board design. There are many kinds of external connections, which should be flexibly chosen according to different characteristics.
Circuit board interconnection mode 1: welding mode
The connection method has the advantages of simple, low cost and high reliability, and can avoid the fault caused by poor contact; the disadvantage is that the exchange and maintenance are not convenient enough. This method is generally applicable to parts with less external leads.
PCB wire welding
This method does not need any connector, as long as the wire will be PCB on the printed circuit board is connected with the external plate external components or other components can be directly welded. For example, speakers in the radio, batteries and so on.
Wiring board shall be paid attention to when welding:
(1) welding pads should be as far as possible on the edge of PCB printed board and arranged in uniform size to facilitate welding and maintenance.
(2) to enhance the mechanical strength of wire connection, avoid wire will be pulled pads or printed conductors should be pulled out, drilling holes near the printed circuit board solder joints in PCB, let the conductor from the printed circuit board welding surface through the hole, and then from the component side pad insert hole welding.
(3) the wire or arranged neatly bundled, card or other fasteners and plate fixation through wire, avoid because of the move and break.
2. PCB line welding
The two PCB boards are connected by line, which is reliable and difficult to connect, and the relative positions of the two PCB printed boards are not limited.
Direct welding between printed boards, usually in connection with a 90 degree angle between two boards. After connecting the PCB board components into a whole.
Circuit board interconnection mode two: connector connection mode
In complex instruments and equipment, plug connection is often used. This kind of "block type" structure not only ensures the quality of mass production of products, reduces the cost of the system, but also 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 trouble and trace it to the specific components. This job requires a considerable amount of time. As long as the board is judged to be out of order, it can be replaced immediately, troubleshooting in the shortest possible time, shortening downtime, and improving the utilization of equipment. The replaced circuit boards can be repaired in sufficient time and used as spare parts after repair.
1. printed board socket
This kind of connection is often used in complex instruments and equipment. In this way, a printed plug is made from the edge of the PCB printed circuit board, and the plug portion is designed according to the size of the socket, the number of points to be received, the contact distance, the position of the positioning hole, and the like so as to be matched with the socket of the special PCB printed board.
In the process of making the plate, the plug part needs gilding treatment to improve the wear resistance and reduce the contact resistance. This method is simple in assembly, good in interchangeability and maintenance. It is suitable for standardization and mass production. The disadvantage is that the cost of the printed board is improved, and the manufacturing accuracy and process requirements of the printed board are higher; the reliability is somewhat poor, and the contact is bad because of the plug part being oxidized or the aging of the socket reed. In order to improve the reliability of the external connection, the same lead line is connected in parallel with the contact on the same side or on both sides of the circuit board.
PCB printed board socket connection mode is often used in multi plate structure products, sockets and printed boards or backplane with reed and pin type two.
2. Standard pin connection
This method can be used for external connections of printed boards, especially in small instruments. The two boards are connected by standard pins, and the two boards are generally parallel or vertical, which is easy to realize mass production.