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The History of Printed Circuit Boards

Printed circuit boards are a crucial part of every computer and digital device in the world today. Available to suit a huge range of electronic applications, PCBs impact just about every aspect of our life, as a result of the 21st century boom in computer and electronics technology.

Operating inside your laptop as you type, they are tucked away in your tablet or smart phone as you scroll social media. They ensure your car runs efficiently, operate the cameras that film your favourite TV shows, run the smart thermostat in your home and make sure the singing birthday card you bought makes your friend smile.

Printed circuit board

© kiri11 / Shutterstock.com

While many people imagine electronics tech to be a modern innovation, the circuit board originally dates back more than 100 years. It is associated largely with the 1980s, when the first personal computers began to emerge.

 

Printed circuit board invention

In actual fact, to chart the origins of the printed circuit board, we need to go right back to 1903, when German scientist Albert Hanson patented his basic circuit board in England that he made for use in telephone systems. A simple design, it consisted of a flat piece of foil attached to wires bonded onto paraffin paper.

Just like today’s plated through-hole printed circuit boards, Hanson’s board had through-hole construction and conductors on both sides. His device bore little resemblance to today’s modern PCBs, but his idea was the forerunner of their creation.

The next step on the printed circuit boards’ journey was taken by Charles Ducas, an American inventor, in 1927. Using a stencil, he printed wires directly onto the board and added ink to conduct electricity. The electronic path was put onto an insulated surface. This device was more recognisable as a printed circuit board.

He also researched the possibility of connecting several boards to create a multi-layered circuit board. However, at the time, he didn’t have the capabilities to do this, although he documented the idea.

 

Development of PCBs

Paul Eisler is usually credited with inventing the printed circuit board as we understand it today. Leaving Austria just before WW2, he settled in England. He had a background in the printing industry and came up with the innovative idea of printing electronic circuits onto boards.

This was a major benefit when compared with the labour-intensive practice of hand-soldering each individual wire to the board. His invention helped Britain’s war effort, as his PCBs were first installed in the radio sets used by the British and American forces to communicate.

After the war, the technology was released to the general public in 1948, starting in the United States, but soon spreading across the world. In the post-war world, the PCBs, also known as printed wiring boards, began to evolve into the high standards we know today.

Transistors were introduced into the electronics market in the 1950s, making it easier to incorporate printed circuit boards and ensuring the products were more reliable.

By the 1960s, PCBs were evolving into double-sided boards with identification printing on one side and electrical components on the other. Designs started to incorporate zinc plates, with corrosion-resistant materials and coatings to prevent degradation.

Improving the speed, power and reliability of any electronic device that incorporated this technology: the integrated circuit (the IC or silicon chip) was introduced into electronic designs, enabling thousands of components to be added on a single chip.

The number of conductors in a printed circuit board increased to accommodate the new technology, resulting in extra layers within the PCB. At the same time, because the IC chips were so tiny, the boards gradually became smaller.

During the 1970s and 1980s, solder-masks of thin polymer materials were developed to enable easier solder application onto the copper circuits. A polymer coating was later developed that could be applied directly to the circuits and modified by photo exposure afterwards when dry. This became the standard PCB manufacturing method.

 

Modern era

New assembly technology was developed in the 1980s, known as surface mount technology. Prior to this, PCB components had wire leads soldered into holes in the PCB. SMT components were developed as the industry standard, as manufacturers could solder them directly onto small pads on the PCB, without the need for holes.

SMT components quickly becoming popular and replaced many of the through-hole components, improving power, performance and reliability, while reducing manufacturing costs. However, through-hole components are still useful for a number of applications today.

During the 1990s, as computer-aided design and manufacturing became more commonplace, PCBs continued to reduce in size. Computerised design began to automate many steps in PCB manufacture, facilitating increasingly complex designs with smaller components. Smaller connections allowed for rapidly increasing PCB miniaturisation.

Now, in the 21st century, printed circuit boards have become significantly smaller and lighter, with higher layer counts. These complex, multi-layered, flexible circuit PCB designs are vastly more functional and efficient in electronic devices, with significantly lower production costs.

To speak with the PCB specialists, please contact Sellectronics. We’d love to discuss your latest electronics manufacturing project and find out how we can help.

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