How are the components connected to each other on the circuit board?
1. Complexity: the bread board only needs wires and components to be plugged in. The operation is complicated, the circuit is chaotic and prone to errors
2. Connection mode: bread board is a connector circuit, PCB is a welding circuit, the former is easy to cause poor contact, the latter is relatively stable
3. Application scope: bread board is suitable for few components, low requirement for signal interference, small circuit current, temporary test circuit, relatively low cost; PCB board has multi-layer type, almost can realize all the circuit welding, grading shielding signal is also called easy to achieve, but need professional software design and processing, high cost
How are the circuit boards connected?
Electronic equipment must be connected according to the circuit schematic diagram, in order to achieve the predetermined function, if the connection error will lead to the entire circuit board invalid, so choose the reliability, technology and economy of the best match connection, is one of the important content of the circuit board design. There are many ways of external connection, which should be flexibly selected according to different characteristics. The following two methods are the most common.
The welding way
This method has the advantages of simple operation, low cost, high reliability, and can avoid failure caused by bad contact. The disadvantage is exchange, maintenance is not convenient. This method is generally applicable to the case of less external leads.
1. PCB wire welding
Do not need any connector, just use a wire to connect the external connection point on the circuit board directly with the components or other components outside the board.
Attention should be paid to the interconnection welding of circuit board:
(1) welding pads of wires should be arranged as far as possible on the edge of circuit board and in a uniform size to facilitate welding and maintenance.
(2) in order to improve the mechanical strength of the wire connection and avoid pulling the pad or printed wire away due to the pull of the wire, drill a hole near the solder joint on the circuit board to allow the wire to pass through the through hole from the welding surface of the PCB, and insert the pad hole from the component surface for welding.
(3) arrange or tie the wires neatly and fix them with wire clips or other fasteners to prevent the wires from breaking due to movement.
2. PCB line welding
The two circuit boards are connected by wiring, which is not only reliable but also not easy to make connection error, and the relative position of the two circuit boards is not restricted.
Direct welding between printed boards, this method is often used for two printed boards between the 90 degree Angle of the connection, after the connection into a whole circuit board components.
Connector connection mode
In the more complicated instrument and equipment, the connector is often used. This “building block” structure not only guarantees the quality of mass production, reduces the cost of the system, and provides convenience for debugging and maintenance. When the equipment fails, the maintenance personnel need not check the component level (that is, check the cause of the failure and trace the source to the specific components. This work needs to spend quite a lot of time), as long as judge which board is abnormal can be immediately replaced, in the shortest time to troubleshoot, shorten the downtime, improve the utilization rate of equipment. The replaced circuit board 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 more complex instruments and equipment. This way is printed from the edge of the circuit board plug, plug part according to the size of the socket, connect points, contact distance, location of the positioning hole design, make it and the special circuit board socket match.
In plate making, the plug part needs to be gilded to improve wear resistance and reduce contact resistance. This method has the advantages of simple assembly, interchangeability and good maintenance performance, and is suitable for standardized mass production. The disadvantages are the higher cost of PCB, the higher requirement of PCB manufacturing precision and technology. Poor reliability, often due to plug parts of poor contact by oxidation. In order to improve the reliability of external connection, the same outgoing wire is often drawn out in parallel through the same side or two side contacts on the circuit board.
2. Standard pin connection
This method can be used for the external connection of printed boards, especially in small instruments often use pin connection. Two printed boards are connected by standard pins. The two boards are usually parallel or vertical, making mass production easy.