PCB is the backbone of the electronics industry. It contains specific circuitry designed to provide the necessary electrical connections between the electrical components and/or parts that are mounted onto it. PCBs are one of the fundamental components found in most electronic products and are commonly used in computers, communication devices, consumer electronics and precision instruments in the automotive and general industry sectors. Conventional PCBs can be broadly classified into three types, namely (i) single-sided; (ii) double-sided; and (iii) multi-layer.
Single-sided PCB is the simplest and most common type of PCB. It was the first device used for the interconnection and assembly of electronic components forming a cohesive and functional operating system. The primary industry that uses these boards is the consumer electronics industry.
Double-sided PCBs have circuitry on both sides of the board with each side connected by metal deposited on the walls of holes divided into the board. The introduction of double-sided PCBs has allowed electronic manufacturers to place components on both sides of the board, thus reducing the overall size of the electronics products. Such a design also shortens and simplifies the length of cross-linking circuitry and allows significant board savings as compared to single-sided PCBs. Double-sided PCBs are suitable for use in medium technology electronic goods such as simple computer peripherals including printers, videos and certain telecommunications products.
Multi-layer PCBs can accommodate a larger number of interconnections than double-sided PCBs and are created by putting more layers with circuitry inside the board. Multi-layer PCBs are commonly used in computers, communications equipment, automobile electronics and other electronic products where space is at a premium.
High Density Interconnect (HDI) PCBs
HDIs have a higher circuit density per unit area than the conventional multi-layered PCBs. They also have a smaller hole diameter, a higher line density and a greater connecting density with more connecting points per square inch than that employed in conventional PCB technology. HDIs are used to reduce size and weight, as well as to enhance the electrical performance of electronic products such as those found in smartphones nowadays.