A brief history of PCBs

Published Wednesday 8th August, 2018

So taken for granted are printed circuit boards, that we barely notice the impact they have on the modern world - but our quick tour through the history of PCBs will show you how we went from relying on bulky wires and valves to the miracles of modern electronics.

The invention of PCBs

It's amazing to think that it was over 100 years ago, in 1903, that the first patent for a PCB-like invention was applied for by German inventor Albert Hanson, who described his idea for a multi-layered insulated board with foil conductors and, what appeared to be, through-hole technology. His brilliance didn't see the light of day for another two decades, however, until Charles Ducas patented his 'printed circuit' - essentially, the first PCB as we'd recognise it today.

It wasn't until 1943 that these incredible ideas could be manufactured and used with any degree of reliability, when Dr Paul Eisler designed and built radios with functional PCBs using his own patented designs – the very same basic board design that we all use today.

Up until this point, electronics manufacturing made do with point-to-point construction, bulky valves and tubes, and unreliable designs – all of which severely limited where electronics could go, but thanks to these pioneers we were about to enter a golden age...

The golden age of PCBs

By 1947 the first double-sided boards were being produced, but they could still only be printed on one side well into the 50s, despite designers experimenting with a number of different materials and resins for the board’s construction. Construction would consist of printed wiring on one side of the PCB and all other components being soldered onto the other side - a process that was efficient and lightweight and allowed for greater innovation in electronics.

The 60s brought us a couple of improvements that changed PCBs forever - namely, the 1963 Hazeltyne Corporation patent application for the first plated through-hole technology, and the development of surface mounted technology (SMT) by IBM.

These innovations meant that boards could be made smaller and more powerful without compromising on reliability by allowing components to be soldered directly to the PCB surface (SMT), and be placed much closer together without the risk of connections crossing over (THT).

The 70s and 80s saw boards shrinking in size and increasing in power yet again as the Japanese developed liquid photo imageable masks (LPIs) - the solder masks that protect boards and help to prevent solder bridges connecting components that should be electronically separate. At this point, the industry started to accept SMT as the most reliable and space-saving mounting solution.

Also by this time, the digital age was in full swing as we saw electronics hitting the high street in everything from:

• Gaming consoles
• The first desktop PCs
• VHS recorders
• Plus many other home appliances

All this was being achieved despite designs still being hand-drawn and boards being constructed by workers in factories, but that would change with the coming of the internet...

The internet age

The 90s was the age of silicone, and the rapid advances in multi-layered circuit boards and flexible technology meant that designers could now fit multiple gates on a single chip and embed memories and Systems on Chips (SoC) together. These advances allowed designers to miniaturise electronics in a way never before thought possible in the manufacture of PCBs.

Computer-aided design and manufacture, along with optical testing and rigorous electrical reliability testing, have created our current situation where PCBs have rock-solid reliability in whatever area they're used.

Going forward, electronics manufacturers are constantly striving to push the boundaries of PCB design to create ever smaller and more powerful electronic devices, and we're proud to play our part in this exciting time in the modern history of PCBs.