In general, the printed circuit boards (PCB) are used in almost all electronic products, except in the simplest ones. Basically, they are connecting the electronic components by using pads, conductive tracks, and other objects. They are designed from single or multiple layers of copper and they can be found everywhere in our daily routine.
In this article we will cover:
1.What are Printed Circuit Boards?
2. What are they used for? And where?
3. Different Types of PCBs.
4. History & Development.
5. The Future of the PCB
What is a Printed Circuit Board?
As we already mentioned a Printed Circuit Board or PCB is a board with the purpose of connecting electronic components. The PCBs structure is alternating layers of conductive copper and layers with nonconductive material with insulation purposes.
During the manufacturing process on the inner layers are left thin traces of copper that will connect the circuit components. Once the copper traces are ready, the insulation material is being laminated to the layers and the printed circuit board is completed.
The electronic components are later added to the outer layers of the printed circuit board only after all the layers are already laminated together.
Having in mind all that, now we are ready to briefly review each of the layers:
1. Copper Layer
In general, the copper layer is a thin foil of copper. It is laminated to the board with adhesive and heat. It is commonly applied on both sides on a double-sided printed circuit board. This is exactly where the naming comes from. Two-laered or double-sided board means that there are two copper layers in the structure. You can find PCBs with only one or more than 16 copper layers!
Basically FR4 is a reinforced epoxy laminate material. It is the base substrate of the printed circuit boards. It is an extremely durable material and there are different thickness types. Some PRBs, especially the cheaper ones, are made from other materials and they lack the FR4 durability.
Have you ever wondered why the PCB boards are green? Because of the soldermask layer. This is the top layer, above the copper foil that is giving the printed boards their green color. The main purpose of this layer is to insulate the copper traces from accidentally contacting any of the solders or metal. Just the common color is green, but have in mind that the soldermask could be manufactured in nearly all possible colors.
Finally, on top of the soldermask, a white silkscreen layer is applied. It is used to insert any numbers, symbols or letters as instruction like a guideline for people to better understand the board. The silkscreen is usually in white color. Again, any color can be used and there are PCBs with yellow, red or even black silkscreen.
As we now covered all the layers and we have a basic understanding of how the PCB boards are created and how they work, it is time to see?
What Are The PCBs Used For?
Printed circuit boards are used in almost everything electrical or electronic. They are the main component of every electrical device we use in our daily routine. They provide us with a variety of capabilities and they have different purposes.
1. Home Applications
The most common application of printed circuit boards or PCBs is in consumer electronics. In fact, millions of people are using their mobile phones, computers and all kinds of entertainment systems and they have no idea that the PCBs are the heart of every electronic device.
By entertainment system, I mean all the desktop personal computers, laptops, workstations, navigations even your TV! You can find printed circuit boards everywhere at home. For example, you microwave, alarm clock, coffee machine, refrigerator even your smartwatch.
2. Industrial Use
There are also industrial applications for the PCBs. Many manufacturing facilities have electronic components that contain printed circuit boards. For example, they are found in industrial equipment such as presses, ramps that are using electronic components, assembly machines and more.
Overall, the industrial sector is demanding an environment that requires a lot of electronic services including a variety of different PCBs.
There is a wide range of applications for PCBs in the automotive industry also. Many of the vehicle systems such as navigation, media devices, control systems, and monitors are using the boards.
Medicine is another place where printed circuit boards find an application, especially in medical devices. All of the scanning equipment, medical instruments, and monitors contain PCBs. For example CT scanners, X-Ray screens, electronic components for the blood pressure monitors and more.
Types of Printed Circuit Boards
As we already discussed what the layers are and how they are created, now we will review some of the most common types of PCBs.
1. Single-Layer PCBs
Single-sided or single-layered is the same when referring to PCBs. These types of boards are the easiest to design. They are used for a variety of applications including radio equipment, calculators, SSD (solid-state drive) and basically in simple electronics compared to multi-layered circuit boards.
There is a high volume of orders for these types of printed circuit boards not only because of the wide-range in which they find application but also because they can be easily found and purchased at low prices.
2. Double-Layered PCBs
The interesting thing here is that the double-layered PCBs have a-holes drilled through the board in order to allow the circuits on the one side to connect with circuits on the other.
However, holes are not the only alternative here to connect circuits located on both sides. Surface-mount is another way to achieve that. In general, many small leads are soldered to the board and used as a wiring surface. In that case, the board is using less space and it is capable of more functions.
Double-sided PCBs are used for example in instrumentation, LED lighting, Vending machines, power supplies, automobile dashboards and more.
3. Multi-Layered PCBs
When there are three or more double-layered PCBs together, it is called a multi-layered board. It?s basically they are putten together by specialized glue and carefully secured preventing heat damage. In fact, the largest printed circuit board ever built is over 50 layers thick!
These types of multi-layered boards are extremely beneficial for data storage, GPS technology, medical equipment, and even satellite systems.
4. High-Frequency PCBs
Here we are referring more to a finished design, rather than a type, but it is still beneficial to know. They are designed specifically to transmit high-frequency signals that surpass over one gigahertz.
There are some specifications when designing high-frequency printed circuit boards:
Water Absorption - This is taken under consideration when a specific order has been made for a board that will be used in wet environments. In the basic designs, a high amount of water intake can affect the board proper functionality and lead to a loss.
Dielectric Loss - It is directly affecting the quality of the transmitted signal. Even a small amount of dielectric loss can lead to a significant signal waste.
5. Rigid PCBs
This type is oriented around preventing the board from twisting. Rigid PCBs are made of the solid substrate material and just for reference, you can check your computer motherboard.
Probably the Rigid PCBs are the most manufactured boards! They can be single, double or multi-layered, up to 10 individual layers.
6. Flexible PCBs
Flexible PCBs are made of a material that can flex and move like plastic. Again, they can be single, double or multi-layered, but they cost more, as they need to be printed on a flexible material.
The flexibility is one of the main benefits of these types of boards. They weigh less, and the material that they are made of is waterproof, corrosion and high-temperature resistant.
History and Development
As we now covered the types and where the printed circuit boards are used, it is time to see where it all began.
In 1925, Charles Dukas developed a way or path for the electricity to follow on an insulated surface. That was the moment when the Printed Circuit Board was born. The design has significantly improved since then in many ways, but the root and the initial idea remains the same.
In a matter of fact, Paul Eisler is considered to be the real founder of the PCB in 1936. He is the developer of a variety of applications which later on grabbed the attention of the US military.
Started from a single layer, nowadays 20+ layers printed circuit boards can be found in your smartwatch. The object that passed through many changes in the years is size.
Before the PCBs, originally the electronic components had wire leads. This is why the PCBs had holes drilled for each of the wires in the components. This method is called ?through-hole construction?. Stanislaus F. Dank and Abramson developed the ?auto-assembly? process in 1949. In that process, the component leads are inserted into a copper foil, which we now call the copper layer.
What?s Next For Printed Circuit Boards?
The manufacturing of PCBs and electronic products is continuing to drive towards a compact and smaller design with increased capabilities. Referring to the future of the printed circuit boards, PCBONLINE has an extremely beneficial blog covering every aspect of the niche, so make sure to visit if you want to learn more useful information.
Some speculations regarding the future of the PCBs may be the integrated circuit chips or the tree-dimensional molded plastic board. The industry is evolving as we speak and this kind of guesses are leading to the constant and dynamic progress in PCB manufacturing.
We cannot be sure what will be the next invention since the PCBs are producing at incredible speed and outstanding complexity. As in every industry, most of the design upgrades are coming from a specific and individual company?s requirements.
As the main part of every electronic system, there is plenty of space for improvement and growth. Most of the predictions for the PCBs future are strongly focused on the following:
1. 3D Printed Electronics
This is probably the most exciting technical invention in the recent decade! It is already beneficial for a variety of industries. I mention this because 3D printing electronics have changed the way we look at the electronics forever. That technology will revolutionize the way electronics systems are created in the future, and the same goes for the PCBs.
2. PCB Cameras
Printed Circuit Board Cameras or also called Board Cameras are specific with that they are mounted directly on the circuit board. In order to fit a camera to a PCB, it has to be very small. In fact small enough that it can fit in about any electronic device. That type of camera might be the future for the PCB designs.
3. PCB Autoplacers
Most of the printed circuit boards that are manufactured today include an autorouter in their design. The whole idea here is to make the automation process easier. Autoroutes are difficult to create and implement, taking a lot of time and work.
The time that the automatization saves is later lost when autoroutes are designed. Many manufacturers are now looking at a autoplacers as the resolution. Autoplacers making the manufacturing process easier and automatization much faster. Unfortunately, the auto-placement tools are not yet accepted in PCBs manufacturing.
However, with the idea of integrated CAD systems the PCB design technology is on a rise recently. The autoplacers need both mechanical and electrical design aspects, the CAD system applies in both realms and it is necessary to make the autoplacers more beneficial and efficient.
PCB technology will continue to grow and improve in the future! PCBONLINE is aware of the newest trends in the PCB industry, and you can find all the information you?re looking for in their BLOG.
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