Printed Circuit Boards are important components of electronic products that have been integrated so much in modern living that we often ignore them. Hence, we are not fully aware of the significant contribution of a printed circuit board not only in making our life more comfortable but also for our survival.
The flourishing printed circuit board industry has penetrated every other type of industry and technology such as medicine, aerospace, automobile, communications, and military. The application of printed circuit nowadays is countless, yet many of us are not aware of it.
Basically, a PCB is a non-conducting substrate sheet with etched copper tracks that converge at various nodes and junctions. The main purpose of a PCB is to connect different electrical parts through the conduction pathways etched on the board. In addition, the actual board provides physical support to the components.
A PCB is mainly of two categories. First is the through-hole circuit board where small holes are punched on the nodes where the part lead will go across the board and they are soldered on the reverse side. This is an old technology but still in use for cheap circuitry applications. Another use of these PCBs is for physical support of heavy parts such as high-rate capacitors and transformers.
The second type of PCB is known as the surface-mounted device circuit board. There are no holes on these boards; but rather they contain small conducting beds where the small parts are mounted and soldered using special tools. This type of PCB has higher mechanical power and either side can be used for parts because there are no holes.
Key Designs of a Printed Circuit Board
There are three main elements of printed circuit boards: a laminate board, the parts mounted on the board, and the wires connecting the parts and forming the circuit.
The actual part used in a PCB wholly depends on the purpose of the circuit. Studying which parts to use is quite detailed and need thorough technical expertise. This leaves us with traces and laminate board. The cost of production, work efficiency and operational costs of the final circuit all depend on these elements.
Of the common materials used for the circuit boards, six are manufactured widely: FR1, FR2, FR3, FR4, CEM1 and CEM3. The FR means flame retardant. FR1, FR2, and FR3 are basically the same with slight differences in their properties. They are not suitable for creating multilayer circuit boards. This is also true with CEM1.
The two laminates that can be used for a multilayer printed circuit boards are FR4 and CEM3, in which the former is massively manufactured and so is less expensive. These two laminates can be used for single and multiple layer boards, and has high thermal tolerance of up to 130 degrees Centigrade.
The most commonly used material for a printed circuit board is copper. Simple techniques involve plating the whole board with copper, and then etching away the unnecessary areas through a stencil to mark the needed traces. More complicated strategies will allow traces to be added on a board with each technique having its own advantages and disadvantages.
There are PCBs that require gold for low-voltage, sensitive applications or to comply with lead-free standard. Using copper traces will require the use of a nickel barrier sheet before plating with gold. This is to stop gold from mixing into the copper. If you want to create your own custom printed circuit board, it is best that you first study the basics of its designs. You can learn from detailed guides and tutorials. Also, there are available online firms that can help you create custom printed circuit boards in less than several days.