What is a PCB?

Abstract: What is a printed circuit board? What does it do? Which electronic devices use circuit boards? I believe that these questions bother many people who do not know about PCB. FS Technology PCBA blog will tell you about this knowledge from the basic concept of PCB to the history of PCB development. Next, let us understand it through a youtube video.

What does PCB stand for in electronics?

PCB is an informal use, printed circuit board or PWB is a more accurate term, but as the concept between circuit and wiring has become blurred, this term has become less and less. PCB refers to conductive paths, tracks, or signal traces etched through copper sheets on a non-conductive substrate to support and electrically connect electronic components. We can understand PCB as the carrier of components. The reason electronic products can function is that the electronic components are connected to each other through the traces on the PCB board to realize the electrical connection between the components. When you search “What does PCB mean” on Google, Google will also push you “What is PCBA”. Although there is only a one-word difference between PCB and PCBA, the meanings are completely different. PCB stands for bare board, a green board that does not function and has no components. PCBA is the meaning of PCB assembly, and the components are mounted on the bare board through SMT, THT and other assembly technologies.

green PCB bare board

Why are PCBs favored by electronics manufacturers?

Circuit boards have been around for nearly 100 years. Not only did it not show any signs of being replaced over the long years, but it was used more and more widely. In the electronics manufacturing industry, PCB as a carrier has unique advantages:

High density: The development of PCB has always been in line with the trend of society. With the dependence of human beings on miniature electronic devices, PCBs show a trend of high density. With the advancement of integrated circuit integration and the development of assembly technology, the electronic component density of PCB has reached its peak.

Schematic of a high-density PCB

High reliability: The production and assembly process of PCB is very complicated. During the whole manufacturing process, the manufacturer needs to carry out many tests. Take a turnkey PCBA company like FS Technology as an example, in addition to the most basic PCB manual inspection and AOI inspection, we also need to carry out a series of aging tests, functional tests, etc. The lifespan of PCB boards from the FS technology factory can reach 20 years.

Designability: The application field of electronic products is very wide. In addition to the common mobile phones and watches in daily life, there are many electronic products that are dedicated to high temperature, high pressure and humid environments. For different application fields, the designability of PCB is the premise that electronic products can meet the different needs of different scenarios.

Productivity: The PCB factory adopts a modern management model, through strict quality management and professional technical means, to achieve a standardized PCB production process, high volume PCB assembly, and fully automatic mechanized production, so as to ensure the consistency of product quality.

Assimilability: The turnkey factory has SMT and THT assembly technologies, which can carry out standardized assembly of various components on bare boards, and perform the automated and large-scale batch assembly. As far as the assembly workshop of FS Technology is concerned, in addition to 7 fully automatic SMT assembly production lines, we can also meet manual plug-in, and mixed assembly processes, even for large-volume PCB DIP assembly orders, we can also achieve automated DIP assembly process.

Maintainability: PCBA finished products are standardized design and large-scale production, so even if the system fails, the turnkey company can quickly, easily and flexibly replace it and quickly restore the system to work.

What types of PCBs are there?

PCBs can be classified in different ways: the number of layers, dimensions, materials, functions, etc. In this article, FS Technology mainly explains the meaning of PCB in electronic products, so we will classify it by the number of layers below so that you can easily understand the types of circuit board.

  • Single layer PCB

This is the most basic and simplest type of PCB. After the bare board is assembled by a turnkey PCBA company, the electronic components are concentrated on one side of the board and the wires are concentrated on the other side. Since single-sided PCBs are subject to many severe restrictions on circuit design, this kind of board is more likely to appear in the early stage of circuit board development.

What is a single-layer PCB?
  • Double layer PCB

This is a type of PCB with wiring on both sides. Since wires are required on both sides of the board, we must build bridges for them – Vias. Vias are small holes in the PCB that are covered with metal, which connect the wires on both sides of the circuit board. Double-sided PCB solves the problem of interleaving wiring when manufacturers make single-sided PCBs, and it is used on more complex circuits than single-sided PCBs.

What is a double-layer PCB?
  • Multilayer PCB

It is a more difficult PCB and its difficulty and price increase with the number of layers. Multilayer PCBs make multiple single- or double-sided boards the inner layers of a multi-layer board through lamination technology. Compared with the first two, multi-layer boards can realize more wiring area, so they are widely used in different electronic products. The number of layers of the multi-layer board will only be displayed as an even number due to the lamination method, which is a mistake that many people who do not understand printed circuit boards will make.

What is a multilayer PCB?

What are the application areas of PCBs?

With the above text, you probably already have a certain understanding of PCB, or at least what it is, right? But even if you have looked through all the electronic devices around you, it is still difficult to find a printed circuit board. As previously mentioned, PCB usually refers to the bare board and the application of printed circuit boards in electronic products we call it PCBA board that is assembled or soldered after the completion of the board. There is a saying on the internet that “without PCBs, it would be impossible to progress in technology today.” This is because PCBs are so widespread in our lives that they are the basic building block of most electronic devices. From your door opener (single layer) to your smartphone (6 layers), to your computer and server (60 layers), they all run on PCBs. The products you come into contact with are finished products that have mechanical assembly (housing + assembled circuit board).

Medical Equipment PCB

With the development of PCB manufacturing industry, the progress of medical technology is obvious to all. Looking back, in the era of underdeveloped technology, doctors use artificial pulse signals to judge patients’ conditions by observing words and expressions. However, it is now possible to use tiny medical electronic devices injected into the human body to observe the patient’s condition. Any high-precision medical equipment (imaging systems, MRI machines, and radiation equipment) is inseparable from the advancement of HDI and SMT, and medical electronics manufacturers are also keen to get medical PCB assembly quotes. Rigid-flexible PCBs are undoubtedly the best solution among different selection types. They gain flexibility while improving reliability. If you don’t know what a rigid-flex PCB board is, you can check the related concepts on our website.

Aerospace equipment circuit board

You read that right, a small PCB board is used in the aerospace industry and has a pivotal position. You may be wondering about this, but when you really understand how the PCB board works, you will understand and accept this fact. Airplanes, satellites, drones and other avionics would not be possible if they were still connected using ancient components. The circuit boards used in the aerospace industry are qualitatively different from those used in our daily lives. They are smaller and more complex products. This kind of PCB is quite difficult to manufacture, and it is impossible to produce it unless it is a professional turnkey PCB assembly company.

PCBA used in aviation equipment

Military Industry

The earliest applicable field of PCB is the military industry, and the United States first used it in military tape recorders. With the advancement of military technology to meet changing customer needs, more and more equipment integrates advanced computerized technology, and ordinary SMT technology has been difficult to meet the requirements of military PCB. They require the electrical and mechanical properties inherent in flexible and rigid-flexible packaging. These types of electronic packages can withstand thousands of pounds of gravity without failing.

PCBA used in military radar

PCB Development History

The development of PCB can be said to be very rapid. Humans never knew what PCB is, and it has only taken a century to become the core of the electronics industry. Before the advent of circuit boards, electrical connections between circuit board components were made through bulky wire connections. The ancient connection method not only wastes material but also complicates the connection between lines.

Our factory is not only equipped with advanced production and inspection equipment but also certified by ISO9001, ISO14001, IATF 16949, ISO13485, and UL. Our products widely applying in telecommunications, computers and networks, medical devices, automotive, industrial controlling systems, new energy, home appliance, etc. History of printed circuit boards is as follows.

  • 1925s

American inventor Charles Ducas patented the first circuit design when he stenciled a conductive material onto a flat board.

  • 1936s

Paul Eisler makes the first printed circuit board for a military radio.

  • 1943s

Eisler etched circuits into copper foil on a glass-reinforced non-conductive substrate.

  • 1944s

The United Kingdom and the United States cooperated for the first time in military weapons.

  • 1948s

In order to popularize PCB and apply it to daily life, the United States first disclosed PCB technology.

  • 1950s

Transistors are introduced to the electronics market in order to reduce the size of electronic products. This move makes the PCB easier to integrate and improves the safety of electronic products.

  • 1950s-1960s

Double-sided PCBs are introduced, with electronic components on one side and logo printing on the other. Zinc sheets are incorporated into the PCB design and feature corrosion-resistant materials and coatings to prevent degradation.

  • 1960s

High-density circuit boards are realized, and integrated circuits (ICs or silicon chips) are introduced into electronic design. This move enables the bare PCB board to carry thousands of electronic components, which greatly improves the power, speed and safety of electronic equipment. Manufacturers program the required functions into smaller chips through IC programming, so that the number of circuit board components used is reduced, thereby reducing the size of the PCBA board. Humans face a new difficulty: how to make welding stronger.

  • 1970s

Printed Circuit Board (PCB) is renamed Printed Wiring Board (PWB). Because the acronym for the printed circuit boards is the same as the acronym for the environmentally harmful chemical PCBs, this confusion leads to public confusion and community health concerns.

  • 1970s to 1980s

Newly developed solder masks of thin polymer materials become the standard manufacturing method for PCBs. A photo-imageable polymer coating was subsequently developed that can be applied directly to circuits, dried and subsequently modified by exposure to further increase circuit density.

  • 1980s

A new assembly technology called Surface Mount Technology (SMT for short) is developed. This soldering directly to small pads on the PCB, without the need for holes, is quickly becoming the standard in PCB manufacturing. PCB SMD components are rapidly gaining popularity, becoming the industry standard, and striving to replace through-hole components, again increasing functional power, performance, and reliability, and reducing electronics manufacturing costs.

  • 1990s

Computerized design automates many steps in PCB design and facilitates increasingly complex designs using smaller, lighter components.

  • 2000s

PCBs became smaller, and lighter, with higher layers and more complexity. Multilayer and flex circuit PCB designs allow for more operational functions in electronic devices, and PCBs are getting smaller and less expensive.

That’s all for “what is a PCB board”, you can find more great articles in the PCB knowledge blog.

More related articles:

What does SMT stand for in electronics?

Four non-profit PCB org sites

What is the difference between SMT and SMD?

What is PCB Board made of?

Latest PCBA Blogs

PCB Surface Finishes

PCB surface treatment is a crucial process in manufacturing and assembly. It is usually applied to the exposed pads and gold fingers to protect them

Read More »