What is Printed Circuit Board or PCB?Posted by Hebe on 6/8/2018 & Updated on 1/9/2018
What roles does PCB play?PCB plays a role in avoiding the mistakes of manual wiring, implementing automatic plug-in or mounting of electronic components soldering tin, and testing as the consistency of PCB, also it has a good quality for electronic devices, improves the labor productivity and saves the cost so that repair after PCB is used in the electronic devices.
How is the printed circuit board developing?The printed circuit board keeps the own trends from single layer to double layer, multilayer and flexible. It can be seen that PCB has a great boom in the developing process of electronic devices with the development of PCB towards high precision, high density, and reliability, and doing well in saving the cost, improving the properties and shortening the volume.
There is no doubt that we have the same opinion on developing trends of PCB manufacturing technology in the future, which move in the direction towards high density, high precision, small hole size, small wiring, small pitch, reliability, multilayer, high-speed transmission, lightweight, and thin type. Hat’s more, it tends to improve PCB manufacturing, saving the cost, reducing the pollution, and being varieties small volume PCB fabrication.
History of Printed Circuit Board (PCB)Paul Eisler, from Austria, the first person to make the printed circuit board, since 1936, he took advantage of PCB in the radio. And in 1943, the printed circuit board was used for military radio in America and in 1948, PCB was formally used for business. So the printed circuit board was popular and it had a great boom since the mid-1950s. The interconnection of electronic components is finished based on wire connection before PCB’s coming. However, now wire is only used for doing an experiment in the lab; it can’t be denied that PCB has to be a leading position in the electronics industry.
What does a PCB consist of?A PCB is mainly made up of a pad, through holes, mounting holes, wirings, components, connectors, fillings, electric boundaries and so on. They play a different role as the following:
- Pad: It is used for soldering plated through hole of components pin.
- Through hole: There are a via with copper and non-metal via, and metal via is used to connect the component pins between each layer.
- Mounting hole: It is used for fixing the printed circuit board.
- Wiring: To connect the electric copper film of component pins.
- Connector: To connect the components between PCB.
- Filling: It is used for copper clad of ground net so that making a great effect on reducing impedance control.
- Electric boundary: It is used for making sure PCB dimension, and the components can’t go beyond its boundary.
What are the Advantages of PCB?The reasons why PCB is popular is that PCB has some special advantages.
High Density : For decades, high-density PCB is updated with the improvement of the integrated circuit integration and mounting technique.
High Reliability : It can make sure that PCB is great to work for a long time with a series of testing.
Designability : There are some demands for PCB properties, it can make a great effect on PCB design with standardizing design. Such as saving the time, and having high fabrication efficiently.
Manufacturability : It can be manufactured with standardization, scale, and automation, and make sure the quality of PCB fabrication consistent by modernization management.
Testability : Set up a great testing way and standard to test and detect the yield and shelf life of PCB.
Mountablity : PCB is not only convenient to mount greatly, but also manufactures automatically and normally. What’s more, PCB and some components are mounting to the large components and machine.
Maintainability : The components are standardizing as PCB and components are designing and manufacturing greatly. So its convenient and fast to change and recover once the system is breaking down.
Why are printed circuit boards usually green in color?There is a confusion about why are printed circuit boards usually green in color for electronics hobbyists and engineers. However, what’s the color of PCB before we learn the question? In fact, that’s called as a solder mask. The purpose of the solder mask is to protect the electronic traces underneath from moisture and dust and to control the flow of molten solder. And there are some other colors for PCB, such as yellow, blue, red, black and so on, so why green? To begin with, it’s the most popular and has a long history to make solder mask with green color. What’s more, it’s cheaper to other colors.
Secondly, as we all know, all the boards need to be PCB fabrication and assembly, there are some processes to pass through the yellow room in PCB fabrication, What’s more, it needs to do HAL, PCBA and AOI test as soldering SMT, which are with optical positioning calibration, so the color of green is easier and effective to pick out.
Thirdly, It is obvious that there are some common colors for PCB, such as red, yellow, green, blue and black. As the problem of process, a lot of lines’ testing is relying on workers to check with eyes in the past, it’s hard and difficult for them to do this work with hard light, so the color of green is good for their eyes. Luckily, now flying probe test is popular to use. However, the color of green continues. Fourthly, the color of blue is mixed with cobalt, and black is carbon, which is conductive, so it’s dangerous to short. Also, the color of green is better for the environment, and it won’t give off a poisonous gas under high temperature.