What Are the Best Tips for Circuit Board Wiring?

The terminal used in the electrical connection of printed circuit boards is known as a PCB terminal or a PCB connector in the industry. It is an accessory product for electrical connection. There is no part on the standard PCB, and it is often called "printed circuit board Wiring Board (PWB) ".

PCB terminal block

Used in printed circuit board electrical connection

Computer and peripherals: motherboard, display, network card, memory card, IC, mouse, router, camera, U disk, fan motor,

Game console, game card board (Gold Finger Board)

Mobile phone: mobile phone board, charger

Electronic anti-theft lock

Audio, printer, copier, fax machine, phone, scanner

1. The similarities and differences between the layers of POWER PCB and PROTEL

Many of us do more than one software for design. Due to the easy-to-use features of PROTEL, many of my friends have learned PROTEL first and then POWER. Of course, there are many direct learning POWER, and there are two softwares used together. Since the two softwares have some differences in layer settings, it is easy for beginners to get confused, so first compare them together. You can also look directly at POWER to have a reference.

First look at the comparison of the classification structure of the inner layer as shown in the following table.

The global PCB industry output value accounts for more than a quarter of the total output value of the electronic component industry. It is the industry with the largest proportion in each electronic component subdivision industry, with an industrial scale of 40 billion U.S. dollars. At the same time, due to its unique position in the electronics basic industry, it has become the most active industry in the contemporary electronic component industry. In 2003 and 2004, the global PCB output value was US $ 34.4 billion and US $ 40.1 billion, with year-on-year growth rates of 5.27% And 16.47%.

Development status of the domestic PCB industry:

China's PCB development began in 1956 and gradually expanded to form the PCB industry from 1963 to 1978. More than 20 years after the reform and opening up, due to the introduction of foreign advanced technology and equipment, single-, double- and multi-layer boards have achieved rapid development, and the domestic PCB industry has gradually developed from small to large. In 2002, China's PCB output value exceeded Taiwan, becoming the third largest PCB producer. In 2003, the PCB output value and import and export value exceeded USD 6 billion, becoming the world's second largest PCB producer. China's PCB industry maintains a rapid growth of about 20%, and is expected to surpass Japan in 2010, becoming the country with the world's largest PCB output value and most active technology development.

From the perspective of output composition, the main products of China's PCB industry have shifted from single-sided and double-sided to multi-layer boards, and they are improving from 4 to 6 layers to 6 to 8 or more layers. With the rapid growth of multilayer boards, HDI boards, and flexible boards, China's PCB industry structure is gradually being optimized and improved.

However, although China's PCB industry has made great progress, there is still a large gap compared with advanced countries, and there is still much room for improvement and improvement in the future. First of all, China entered the PCB industry relatively late. There is no dedicated PCB research and development institution, and it has a large gap with foreign manufacturers in some new technology research and development capabilities. Secondly, from the perspective of product structure, production is still dominated by middle and low-level boards. Although FPC and HDI are growing rapidly, the proportion is still not high due to the small base. Thirdly, most of China's PCB production equipment depends on imports, and some core raw materials can only rely on imports. The incomplete industry chain also hinders the development of domestic PCB series enterprises.

PCB industry chain

Classified according to the upstream and downstream of the industrial chain, it can be divided into raw materials-copper clad laminates-printed circuit boards-electronic product applications. The relationship is simply expressed as:

Fiberglass cloth: Fiberglass cloth is one of the raw materials of copper clad laminates, which is woven from glass fiber yarn, which accounts for about 40% (thick) and 25% (thin) of the cost of copper clad laminates. Glass fiber yarns are calcined in a kiln to form a liquid from raw materials such as silica sand. They are drawn into extremely fine glass fibers through extremely small alloy nozzles, and then hundreds of glass fibers are entangled into glass fiber yarns. The investment in the construction of the kiln is huge, generally requiring hundreds of millions of dollars, and once it is ignited, it must be produced continuously for 24 hours, and the cost of entry and exit is huge. The manufacturing of fiberglass cloth is similar to that of weaving enterprises. It can control the production capacity and quality by controlling the speed, and the specifications are relatively single and stable. Since the Second World War, there has been little change in specifications. Unlike CCL, the price of glass fiber cloth is most affected by the relationship between supply and demand. In recent years, the price has fluctuated between 0.50-1.00 USD / meter. Taiwan and mainland China account for about 70% of the global production capacity.

Copper foil: Copper foil is the raw material that accounts for the largest proportion of the cost of copper clad laminates. It accounts for about 30% (thick) and 50% (thin) of the cost of copper clad laminates. Therefore, the price increase of copper foil is the main driving force for the price of copper clad laminates. The price of copper foil is closely reflected in the price change of copper, but the bargaining power is weak. With the rising price of copper, the situation of copper foil manufacturers is difficult. Many companies are forced to close down or be merged, even if the copper clad laminate manufacturers accept the price of copper foil. The rise of various copper foil manufacturers is still at a general loss. Due to the emergence of the price gap, another wave of price increases is likely to occur in the first quarter of 2006, which may drive CCL prices up.

Copper-clad laminate: Copper-clad laminate is the product of pressing glass fiber cloth and copper foil together with epoxy resin as a fusion agent. It is the direct raw material of PCB. It is made into a printed circuit after etching, electroplating, and lamination of multilayer boards. board. The capital demand of the copper-clad laminate industry is not high, about 30-40 million yuan, and production can be stopped or changed at any time. In the upstream and downstream industry chain structure, CCL has the strongest bargaining power. Not only can it have a strong right to speak in the procurement of raw materials such as fiberglass cloth and copper foil, but as long as downstream demand is acceptable, it can pass the pressure of rising costs. Downstream PCB manufacturers. The price of copper-clad laminates began to increase by about 5-8%. The main driving force was to reflect the rise in copper foil prices, and the strong downstream demand could absorb the price pressure passed on by CCL manufacturers. Nanya, the world's second largest copper-clad laminate manufacturer, also raised its product prices on December 15, 2005, showing that PCB demand is in good shape at least in the first quarter of 2006.

As the most widely used electronic component product, PCB has strong vitality. No matter from the perspective of supply and demand or from the historical cycle, the beginning of 2006 is the stage when the industry has entered a boom. The continued strong downstream demand has pulled the shipments of various manufacturers in the PCB industry chain layer by layer, forming at least 2006 In the first quarter of this year, the "off-season is not weak" situation. Upgrade the industry rating from "Avoid" to "Good".

PCB is the most basic component of the information electronics industry, and belongs to the electronic component industry in the electronic component industry. According to the number of layers, PCBs are divided into single-sided board (SSB), double-sided board (DSB), and multilayer board (MLB); according to softness, PCB is divided into rigid printed circuit board (RPC) and flexible printed circuit board ( FPC). In industrial research, the PCB industry is generally subdivided into six major subdivisions, such as single-panel, double-panel, conventional multilayer boards, flexible boards, HDI (high-density sintering) boards, and packaging substrates, according to the basic classification of the above PCB products. industry.

The PCB industry is a typical cyclical industry. Historically speaking, the period is generally 7-8 years, but with the acceleration of the downstream demand update speed, it is gradually shortened to about 4 years. Unlike LCD panels and memory products, the price trend of CCL is mainly driven by the cost of raw materials, while the price of PCB is greatly affected by the balance between supply and demand.

Also called needle pitch, 3.50mm / 3.81mm / 5.00mm / 5.08mm / 7.50mm / 7.62

Depending on the company's situation, PCB terminals are divided into plug-in terminals, screw-type terminals, spring-type terminals, and fence-type terminals, but the specific models are different for different companies.

Plug-in terminal

The product has 2-24 wires with a pitch of 3.5, 3.81, 5.0, 5.08, 7.5, and 7.62. It can provide sockets with screw fixing for matching and shock-resistant connection. The plug uses side connection technology, that is, the direction of the screw is perpendicular to the direction of the wire.

Screw terminal block

Circuit board terminals have always played an important role in the electronics industry, and have now become an important part of printed circuit boards. Its structure and design are more sturdy in terms of convenient wiring and reliable screw connection; compact structure, reliable link, and its own advantages; the use of the principle of clamping body lifting to ensure reliable wiring and large wiring capacity; solder feet and clamping wire The body is divided into two parts to ensure that the distance when tightening the screws will not reach the solder joints and damage the solder joints; the shell is firm and reliable, and the pitch is accurate.

Spring-loaded printed circuit board terminal

Spring-type printed circuit board terminals, providing 2.54mm, 3.50mm, 5.00mm, 7.50mm, 7.62mm, etc .; single core wire can be directly inserted without the assistance of the handle, but smaller wires can be opened with the handle to open the clip. Wire clamping; no key specifications, so that the height can be greatly reduced, and the wire can be easily taken out with a screwdriver when the wire is withdrawn; most of the spring-type terminals are combined one by one; the wiring method is very suitable for communication systems , Lighting system, monitoring system and building wiring; various wiring directions, favorable assembly in a small space, the number of contacts can be arbitrarily combined, easy operation, suitable for high-density wiring needs.

Fence type terminal

Fence type model code is LW; middle pin position code is C; side pin position code is B; fixed position code is M; loop pin type code is R; wire type code is Q; LW fence type product has simple structure and plate type Crimping method, intuitive and firm; diameter range: 0.5m-6m;

PCB terminals (also known as circuit board terminals) are usually difficult to identify because customers usually do not disassemble them. Several simple and convenient ways to identify.

1. First of all, there are one or several iron die-casting lines in the appearance of die-casting, which is a line protruding.
2. Secondly, the difference in weight is that copper is more important than zinc.
3. Finally, the difference in color, the appearance of the electroplated layer was polished away, the appearance of gold is copper, white zinc.