Every electronic device ranging from computers, televisions, laptops, and so would require electricity to work. From the source, electricity is then channeled through electronic circuits to make the electronic device work. Of course it takes a complicated circuit for electricity to work. That's why PCBs are created to better organize an electronic circuit. What exactly is the PCB, why PCB is needed, made of what material and what are its types? Let's look more deeply about the understanding of PCB in the article below.
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[source](https://www.eso-electronic.com/en/knowledge-base/manufacturing/article/why-dry-your-printed-circuit-boards-pcbs/)</center>
## Understanding PCB
PCB is an abbreviation of Printed Circuit Board (sometimes called as printed wire board), which is used worldwide as the core component of any electronic device or instrument. This PCB is physically a device used to connect electronic components in a circuitry with its conductor path layers. PCB itself has grown since tens of years ago. Here is a brief history of PCBs in the world of electronics:
* 1936: Paul Eisler, an Austrian scientist, first invented the PCB. He uses this circuit board for the formation of a radio.
* 1943: The United States subsequently adopted this circuit board in military radio in large numbers.
* 1948: The first time PCBs were commercialized in the United States
* 1950: After this year, PCB has been used in mass in various sectors, especially in electronics industry.
## PCB function
So what are the functions of this PCB? In general, PCBs that are widely used both in computer devices and other electronic devices have the following functions:
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[source](https://grabcad.com/library/pcb-usb-asp)</center>
* Place composing electronic components so that they are installed more neat and organized.
* Connecting the legs of the components to each other, both legs of active and passive components.
* Cable replacement to connect various components, thus requiring a more efficient place.
* For making the appearance of an electronic circuit more neat and orderly.
## PCB Shaper Layer
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[source](https://www.alibaba.com/product-detail/Via-type-PTH-applications-for-telecom_60524913637.html)</center>
Although if seen at a glance, PCB is just a board, but the board turns out to have several layers with different material compilers. One can imagine, the layer to be similar to a layer cake. Here is the structure and composition of the PCB.
#### 1. Substrate (Standard Layer)
The first layer material that is usually the basis of a PCB is called the substrate, which can be **FR2** (Flame Resistant) and **FR4**. Flame resistant 2 is a term that refers to synthetic resin bonfing paper. FR2 is made by making a sheet of paper covered by plastic resin. The plastic resin used is a chemical called **formaldehyde phenol**.
Meanwhile, FR4 itself is made of fiberglass woven that has undergone a coating process with epoxy resin. When compared to FR2, FR4 has a lower water absorption, making it a material with good insulation power that also has resistance to temperatures up to 140 degree celcius. With this quality, PCB made from FR4 substrate is more expensive than FR2.
#### 2. Copper
The next layer is a flat copper that is glued to the substrate by laminating at a certain temperature. Because the PCB itself there are two types, then the number of copper layers depends on the type of PCB. For Single Sided PCBs, it will only be coated by a single layer of copper on one side of the substrate, while for Double Sided, on both sides is coated with copper. Technological developments are now more advanced so that copper coating was adjusted premises needs. There are also coated PCBs up to 16 copper layers due to the needs of the desired electronic circuit.
#### 3. Soldermask
Represents a layer after copper, whose function is to keep the copper layer and conductor paths from unintentional contact. **Soldermask** is also quite important to prevent the occurrence of solder short (short solder relationship). Generally, the soldermark layer has a green color, and some are blue or red.
#### 4. Silkscreen
Serves to provide indicators or marks for electronics components that are assembled on PCB, so that people more easily assemble a series. This silkscreen is usually white or black, with printed letters, numbers, and symbols on the PCB.
## Types of PCBs
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[source](http://www.dnatechindia.com/pcb-printed-circuit-board-types.html)</center>
As previously mentioned, PCB can generally be divided into three types based on the number of layers, single layer PC (single sided) and double layer (double sided) PCB, and multilayer. Of the three types of PCB, then divided again into several kinds.
* Single Sided PCB: It is a type of PCB that has only one layer of copper component on one side of its substrate.
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[source](http://www.dnatechindia.com/pcb-printed-circuit-board-types.html)</center>
Single Sided PCB type is widely used for various simple electronic circuits with relatively low cost production.
* Double Sided PCB: On the other hand, double side PCB is a PCB type with two layers of copper on each side of its substrate.
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[source](https://www.datarespons.com/high-density-interconnect/)</center>
Usually, there are holes that serve as connecting both layers of copper.
* Multilayer PCB: It has several layers of copper (which is more than 2 layers. An interlayer layer on a multilayer PCB separated by an insulator layer, usually used for complex electronic circuits that require quite a lot of conductors. There are several types of multilayer PCBs, some are 4, 6, 10, up to 16 layers depending on the complexity of the circuit.
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[source](http://www.unitechelectronics.com/ourservices.htm)</center>
In addition to its own based layer, PCB can also be grouped based on flexibility, meaning that the rigid or not PCB is for a series. Based on its flexibility, PCB is divided into 3 kinds:
* Rigid PCB : That is, the circuit board is rigid and can not be flexed or folded. Useful for rigid substrate materials like fiberglass.
* Flex PCB (Flexible): The substrate is made of plastic material that is fairly easy to bend, flex and regulate. By using Flex PCB, the circuit is easily bend without damaging it.
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[source](http://www.zseries.in/electronics%20lab/pcbs/)</center>
* Rigid-Flex PCB: The combination of rigid and flexible PCB. Usually, some Rigid PCBs are connected by using Flex PCB.
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[source](http://sblog.pw/rigid-flex-circuit-board-design-curbs-medical-wearable-gadget-issues/)</center>
These are the illustrations of the notion of PCB, its function, the material of formation, and its types. Hopefully the article above useful for you who like to assemble electronic devices to make the circuit more neat and organized.
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References used:
* http://www.dnatechindia.com/pcb-printed-circuit-board-types.html
* https://www.datarespons.com/high-density-interconnect/
* http://sblog.pw/rigid-flex-circuit-board-design-curbs-medical-wearable-gadget-issues/
* https://www.matz.in/work_item/pcb-fabrication
* https://www.elprocus.com/different-types-printed-circuit-boards/
* https://www.linkedin.com/pulse/practical-pcb-layout-tips-every-designer-needs-know-thea-lu
***
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