Electronic components and electromechanical components have electrical contacts, and the electrical connection between two discrete contacts is called interconnection. Electronic devices must be interconnected in accordance with the circuit schematic to achieve the intended function.
As a part of the whole machine, a printed board generally cannot constitute an electronic product, and there must be a problem of external connection. Electrical connections are required between printed boards, printed boards and off-board components, printed boards and equipment panels. The selection of the best combination of reliability, process and economy is one of the important contents of printed board design. There are many ways to connect externally, and you have to choose flexibly according to different characteristics.
Circuit board interconnection method
The connection method has the advantages of simplicity, low cost, high reliability, and can avoid failure caused by poor contact; the disadvantage is that the interchange and maintenance are not convenient. This method is generally applicable to the case where the component has fewer external leads.
1, PCB wire welding This method does not require any connectors, as long as the wires are used to directly solder the external connection points on the PCB printed board to the components or other components outside the board. For example, a speaker in a radio, a battery case, and the like.
Pay attention to the interconnection of the board when soldering:
(1) The pads of the soldered wires should be as close as possible to the edge of the PCB printed board and arranged in a uniform size to facilitate soldering and maintenance. (2) In order to improve the mechanical strength of the wire connection, to avoid the wire or the printed wire being pulled off due to the pulling of the wire, the hole should be drilled near the solder joint on the PCB printed board, so that the wire is worn from the soldering surface of the printed board. Through the via hole, insert the pad hole from the component surface for soldering. (3) Arrange or bundle the wires neatly and fix them with the plate by wire cards or other fasteners to prevent the wires from breaking due to movement.
2, PCB cable welding The two PCB printed boards are connected by a cable, which is reliable and difficult to connect, and the relative positions of the two PCB boards are not limited.
Direct soldering between printed boards, this method is often used for a 90 degree angle between two printed boards. Once connected, it becomes a unitary PCB printed board component.
In more complicated instruments and equipment, the connector connection method is often used. This "building block" structure not only ensures the quality of the mass production of the product, 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, trace the source to the specific components. This work takes a considerable amount of time), as long as it is determined which board is not normal, It can be replaced immediately, troubleshooting in the shortest time, reducing downtime and increasing equipment utilization. The replaced circuit board can be repaired in a sufficient amount of time and used as a spare part after repair.
1, printed board socket This type of connection is often used in more complex instruments. In this way, the printed plug is made 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 contact, the position of the positioning hole, etc., so as to match the special PCB printed board socket.
When making the board, the plug part needs to be gold-plated to improve wear resistance and reduce contact resistance. This method is simple to assemble, interchangeable, and has good maintenance performance, and is suitable for standardized mass production. The disadvantage is that the manufacturing cost of the printed board is improved, the manufacturing precision and the process requirements of the printed board are high; the reliability is slightly poor, and the contact is often poor due to oxidation of the plug portion or aging of the socket spring. In order to improve the reliability of the external connection, the same lead wire is often taken in parallel through the contacts on the same side or both sides of the circuit board.
The PCB printed circuit board socket connection method is often used for multi-board structure products, and the socket and the printed board or the bottom plate have two types of reed type and pin type.
2, standard pin connection This method can be used for the external connection of the printed board, especially in small instruments. The two printed boards are connected by standard pins, which are generally parallel or perpendicular, making mass production easy.
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