Before outlining the History of a Printed Circuit Board, or PCB, lets look at what a PCB is and does.
Along with wire wrap and point to point construction, PCB’s are the most common element used to make nearly all electronics devices work. They are self-contained electronic mediums that mechanically supports and utilizes electricity to connect electronic components with features such as conductive tracks, pads and etched copper sheets. More specialized or ‘advanced’ PCB’s may also contain embedded components such as capacitors, resistors or active devices. They are found in our common everyday electronic devices such a radios, televisions, mobile phones and refrigerators; anything that requires electricity to work. The complexity of a circuit board depends on a variety of factors such as size, use, battery life, cables used and portabilityof the electronic device.
There are two other types of circuit assemblies that are used; one being an integrated circuit (IC or microchip), which performs similar functions to a PCB except the IC, contains many more circuits and components that are electrochemically put in place on the surface of a very small chip of silicon. The second is a hybrid circuit looks like a standard PCB, but contains some components that are ‘grown onto’/placed within the surface of the substrate rather than being placed on the surface and soldered.
Printed Circuit Boards evolved from electrical connection systems that were developed in the 1850s. Metal strips/rods were previously used to connect large electric components that were first mounted on wooden bases. Soon after the metal strips were replaced by wires that were connected to screw terminals, whilst the previously used wooden bases were replaced by metal frames. This new invention originated in England but soon became a global phenomenon in the electronics manufacturing industry.
‘Wire wrap’ and ‘point-to-point’ units were used previous to 1943, when in 1936 an Austrian Engineer by the name of Paul Eisler invented a prototype PCB, whist working on a radio set. The US used this invention to make large scale proximity fuses to use in the world war at the time (1943, WWII). 1948 the war had ended a few years before this time and the US now manufactured PCB’s strictly for commercial use. The 1950’s brought on ‘Auto- Sembly’ , an automated line of assembling the boards, which sparked in increase in popularity and consumption in the electronics industry.
It seemed that these large designs were becoming impractical, as they required smaller and more compact systems to be able to cope with larger amounts of data as well as fit in the modern designs of new electrical appliances. A new method was applied to create an electrical path directly on an insulated surface by printing through a stencil with electrically conductive inks, later named "printed wiring" or "printed circuit."
Single-sided PCB’s were common in the 1950s and 1960s. In the late 1960s and early 1970s, technological advancements enabled plating to the drilled hole walls which then enabled connection of electronic components on either side, creating a double-sided board.
By the 1980s, ‘multilayer’ circuit boards, which include several layers of a typical ‘single-sided’ board are placed one on top of another. A more diverse and complex process purposefully built for modern computers and telecommunications equipment. The next step form here were small surface mount parts which are used instead of through-hole components, allowing the construction of a smaller sized board; more functional as well as reducing production costs, however, servicing these boards requires a little more effort then a standard sized board.
Components on a PCB are connected electronically to the designed circuits by two different methods. The first method is called "Through Hole Technology" and the second and newest method is called "Surface Mount Technology." Through Hole Technology requires a component that has thin wires, or leads, which are pushed through small holes in the substrate and soldered to connection pads in the circuits on the other side of the board. The contact with the holes and pull of gravity between the leads and the sides of the holes enables the components to stay in place until they are soldered. Surface Mount Technology has stubby J-shaped or L-shaped legs on each component keeping contact with the printed circuits directly. A solder paste consisting of glue, flux, and solder are then applied at this point of contact to allow the components to be held in place until the actual solder is melted or "reflowed," in an special oven to make the final connection complete. Although surface mount technology requires greater attention and care in the placement of the components, its benefits are that it eliminates the time-consuming drilling process as well as the space-consuming connection pads characteristic with Through Hole Technology. In today’s manufacturing, both technologies are frequently used.
A thin layer of conducting material deposited or ‘printed’ on the surface of an insulating board known as the substrate that will then be able to form the circuits. The substrate most commonly used in PCB’s is a glass fiber reinforced (fiberglass) epoxy resin with a copper foil bonded on to one or both sides. PCBs made from paper-reinforced phenolic resin with a bonded copper foil are less expensive and are often used in household electrical devices.
Fabricators and designers will generally choose to use a heavier copper when manufacturing boards as the thicker the copper, the more resistant to thermal stains and increase in current carrying capacity the board will have. This is then coated in tin to prevent oxidation (rusting) of the copper.
When a complete board has only copper connections, but no embedded components it is more correctly titled ‘Printed Wiring Board (PWB). Likewise, A PCB occupied with electronic components is called a Printed Circuit Assembly (PCA). The term PCB is used informally both for bare and assembled boards.
As can be seen, the Printed Circuit Board industry has come a long way through the various technological advancements in production methods as well as new integrated design methods for more and new superior yet simplistic electronics devices that we use in everyday life such as mobile phones, tablets, complex machinery and aircraft technology. Today it is simple and easy as all geographical boundaries and broken with the introduction of the online shopping phenomenon through e-commerce websites, from simple to high-tech custom made Printed Circuit Boards can be quoted and ordered online.
Our company PCB Global prides itself on our innovative technologies enabling PCB Global to also offer our Full Spectrum capabilities for 1 Layer to 40 layer Printed Circuit Boards with a multitude of substrates and technologies for Standard, Fast and Express quick-turn prototype manufacturing, low to medium volume pre-production to high volume mass production. In an ever-changing world of technological advancements, at PCB Global, we believe in the importance of continuously advancing our ideas, knowledge and experience in order to follow through and become the pioneers in taking the lead of these technological advancements, leading towards an innovative future in the electronics industry.