PCB Blog - Introduction to electronic board

Electronic boards are one of the important electronical components in the electronic industry.Almost every electronic device, from electronic watches and calculators to computers, communication electronics, and military weapon systems, requires the use of printed circuit boards to electrically interconnect electronic components such as integrated circuits.

The circuit board is composed of an insulating base plate, connecting wires, and a solder pad for assembling and welding electronic components, which has the dual function of conducting wires and insulating base plates. It can replace complex wiring and achieve electrical connections between various components in the circuit, not only simplifying the assembly and welding work of electronic products, reducing the workload of traditional wiring methods, and greatly reducing the labor intensity of workers.Moreover, it reduces the overall volume, reduces product costs, and improves the quality and reliability of electronic equipment.

Characteristics

The reason why PCB has been increasingly widely used is because it has many unique advantages.

Can be high-density

For many years, the high density of printed boards has been able to develop correspondingly with the improvement of integrated circuit integration and the advancement of installation technology.

High reliability

Through a series of inspection, testing, and aging tests, it is possible to ensure that PCBs can work reliably for a long time (usually with a lifespan of 20 years).

Designability

The requirements for various properties of PCBs (electrical, physical, chemical, mechanical, etc.) can be achieved through design standardization and standardization. This design has a short time and high efficiency.

Producibility

PCB board adopts modern management, which can achieve standardization, scale (quantity), and automated production,thereby ensuring the consistency of product quality.

Testability

We have established relatively complete testing methods and standards, which can be used to detect and evaluate the qualification and service life of PCB products through various testing equipment and instruments.

Assemblability

PCB products are not only convenient for the standardized assembly of various components but also for automated and large-scale mass production. In addition, assembling a PCB as a whole with various other components can also form larger components, systems, and even the entire machine.

Maintainability

Due to the standardized design and large-scale production of the components assembled as a whole with various components in PCB products, these components are also standardized. So, once the system malfunctions, it can be quickly, conveniently, and flexibly replaced to quickly restore the system's operation.

PCB has other advantages, such as miniaturization, lightweight, and high-speed signal transmission.

Functions of electronic boards

Electronic boards have the following functions in electronic devices.

(1) Provide mechanical support for fixing and assembling various electronic components such as integrated circuits, achieve wiring and electrical connections or insulation between various electronic components such as integrated circuits, and provide the required electrical characteristics.

(2) Provide solder mask graphics for automatic welding, and identification characters and graphics for component insertion, inspection, and maintenance.

(3) After using printed boards in electronic equipment, due to the consistency of similar printed boards, manual wiring errors are avoided, and electronic components can be automatically inserted or pasted, soldered, and inspected, ensuring the quality of electronic products, improving labor productivity, reducing costs, and facilitating maintenance.

(4) Provide the required electrical characteristics, characteristic impedance and electromagnetic compatibility characteristics for the circuit in the high-speed or high-frequency circuit.

(5) The electronic board with embedded passive components provides certain electrical functions, simplifies electronic installation procedures, and improves product reliability.

(6) In large-scale and ultra-large-scale electronic packaging components, it provides an effective chip carrier for miniaturized chip packaging of electronic components.

Classification

1.Classification by purpose

Civil printed circuit boards (consumer): pcb plate used in toys, cameras, televisions, audio equipment, mobile phones, etc.

Industrial printed circuit boards (equipment category): printed circuit boards used in security, automotive, computer, communication machines, instruments and meters, etc.

Military printed circuit boards: printed circuit boards used in aerospace and radar.

2.Classification by substrate type

Paper-based printed circuit boards: phenolic paper-based printed circuit boards, epoxy paper-based printed circuit boards, etc.

Glass cloth-based printed circuit boards: epoxy glass cloth-based printed circuit boards, polytetrafluoroethylene glass cloth-based printed circuit boards, etc.

Synthetic fiber printed circuit boards: epoxy synthetic fiber printed circuit boards, etc.

Organic film substrate printed circuit board: Nylon film printed circuit board, etc.

Ceramic substrate printed circuit board.

Metal core-based printed circuit board.

3. Classification by structure

According to the structure, electronic boards can be divided into rigid printed circuit boards, flexible printed circuit boards, and rigid-flexible combination printed circuit boards.

4. Classification by layer

Printed circuit boards can be divided into single-panel, double-sided boards, multi-layer boards, and HDI boards (high-density interconnect boards) according to the number of layers.

1) Single panel

Single panel refers to a circuit board where wiring is only carried out on one side (welding surface) of the circuit board, and all components, as well as component labels and text annotations, are placed on the other side (component surface).

The biggest characteristic of a single panel is its low price and simple manufacturing process. However, because wiring can only be carried out on one surface, it is difficult to do so and may lead to difficulty in wiring. Therefore, it is only suitable for some relatively simple circuits.

2) Double-sided board

Dual panels are wired on both sides of the insulation board, with one side serving as the top layer and the other side serving as the bottom layer. The top and bottom layers are electrically connected through vias.

Usually, the pcb components on the double-layer board are placed on the top layer; However, sometimes to reduce the size of the circuit board, components can also be placed on both layers. The characteristics of double-layer boards are moderate price and easy wiring, making them a commonly used type among ordinary circuit boards.

3) Multilayer board

Printed circuit boards with two or more layers are collectively referred to as multilayer boards.

4) HDI board

HDI board is a pcb board that uses micro blind buried hole technology and has a relatively high density of circuit distribution.

Structure

Electronic boards are mainly composed of copper-clad laminates (CCL), semi-cured sheets (PP sheets), copper foil (Copper Foil), and solder masks (also known as solder masks). At the same time, to protect the exposed copper foil on the surface and ensure the welding effect, it is also necessary to perform surface treatment on the PCB, sometimes accompanied by characters for identification.

Electronic boards have good product consistency and can adopt a standardized design, which is conducive to achieving mechanization and automation in the production process. At the same time, the entire assembled and debugged printed circuit board can serve as an independent spare part, facilitating the exchange and maintenance of the entire product. At present, they have been widely used in the production and manufacturing of electronic products.