With the expansion of computer technology and electronics into virtually every aspect of our lives, it is easy to dismiss or disregard the foundation which they are built upon: printed circuit boards, or PCBs. Although they have become ubiquitous in our daily activities, electronics and their components have only been around for about a century. The printed circuit boards (PCBs) used in today’s electronics equipment were first designed and developed in the 1930s.
In 1936, Austrian inventor Paul Eisler developed the first PCB to operate a radio system, based on a circuit design originally patented by Charles Ducas. The technology was quickly picked up by the United States military and used in proximity fuses during World War II. The technology was released to the public in 1948, and printed circuit boards, also known as printed wiring boards (PWBs), started to evolve.
In order to help you follow the history of PCB boards, here we provide a timeline that overviews the primary discoveries, changes, and breakthroughs that have made PCBs what they are today.
PCBs Throughout the Years
The first PCBs are nearly unrecognizable compared with modern designs. The fundamental premise was to create an electrical path on an insulated substrate to facilitate the control and movement of electrical current. Over the years, numerous changes and adjustments were made to improve upon the concept. Material developments and computerization aided the continued evolution of the PCB into multi-layered boards, flexible circuits, rigid-flex hybrid boards, and miniaturized designs used in modern electronics.
PCB Evolution Timeline
- 1925: Charles Ducas, an American inventor, patents the first circuit board design when he stencils conductive materials onto a flat wooden board.
- 1936: Paul Eisler develops the first printed circuit board for use in a radio set.
- 1943: Eisler patents a more advanced PCB design that involves etching the circuits onto copper foil on glass-reinforced, non-conductive substrate.
- 1944: The United States and Britain work together to develop proximity fuses for use in mines, bombs, and artillery shells during WWII.
- 1948: The United States Army releases PCB technology to the public, prompting widespread development.
- 1950s: Transistors are introduced to the electronics market, reducing the overall size of electronics, and making it easier to incorporate PCBs and dramatically improving electronics reliability.
- 1950s-1960s: PCBs evolve into double-sided boards with electrical components on one side and identification printing on the other. Zinc plates are incorporated into PCB designs and corrosion-resistant materials and coatings are implemented to prevent degradation.
- 1960s: The integrated circuit – IC or silicon chip – is introduced into electronic designs, putting thousands and even tens of thousands of components on a single chip – significantly improving the power, speed, and reliability of electronics that incorporate these devices. To accommodate the new IC’s the number of conductors in a PCB had to increase dramatically, resulting in more layers within the average PCB. And at the same time, because the IC chips are so small, the PCBs begin to grow smaller, and soldering connections reliably becomes more difficult.
- 1970s: Printed circuit boards are incorrectly associated with the environmentally harmful chemical polychlorinated biphenyl, which was also abbreviated as PCB at the time. This confusion results in public confusion and community health concerns. To reduce confusion, printed circuit boards (PCBs) are renamed printed wiring boards (PWB) until chemical PCBs are phased out in the 1990s.
- 1970s – 1980s: Soldermasks of thin polymer materials are developed to facilitate easier solder application onto the copper circuits without bridging adjacent circuits, further increasing circuit density. A photo imageable polymer coating is later developed that can be applied directly to the circuits, dried, and modified by photo exposure afterward, further improving circuit density. This becomes a standard manufacturing method for PCBs.
- 1980’s: A new assembly technology is developed called surface mount technology – or SMT for short. Previously all PCB components had wire leads that were soldered into holes in the PCBs. These holes took up valuable real estate that was needed for additional circuit routing. SMT components were developed, and quickly became the manufacturing standard, that were soldered directly onto small pads on the PCB, without needing holes. SMT components proliferated quickly becoming the industry standard, and worked to replace through hole components, again improving functional power, performance, reliability as well as reducing electronic manufacturing costs.
- 1990s: PCBs continue to decrease in size as computer-aided design and manufacturing (CAD/CAM) software becomes more prominent. Computerization design automates many steps in PCB design, and facilitates increasingly complex designs with smaller, lighter components. The component suppliers work simultaneously to improve the performance of their devices, reduce their electrical consumption, increase their reliability, while at the same time reducing cost. Smaller connections allow for rapidly increasing PCB miniaturization.
- 2000s: PCBs have become smaller, lighter, much higher layer counts and more complex. Multi-layered and flexible circuit PCB designs allow for vastly more operational functionality in electronic devices, with increasingly smaller and lower cost PCBs.
Printed Circuit Boards Today
Today, printed circuit boards have outlived the stigma of chemical PCBs and are openly referred to as PCBs without confusion. This is largely due to the phasing out of chemical PCBs over the past four decades. The terms printed circuit board and printed wire board (PWB) are now used interchangeably in the industry, though printed circuit board is now the more common term.
As printed circuit boards continue to evolve, they can be expected to grow ever smaller and more complex. The latest innovation in PCB technology—the rigid flex PCB—combines the complexity and reliability of a hardboard circuit with flexible layers that are incorporated into the rigid structure. With these combined layers, rigid-flex PCBs are smaller, thinner and can fit into unusually shaped or especially small products.
The Latest PCB Technology by Printed Circuits
Since 1977, Printed Circuits has been at the forefront of PCB technology. We pride ourselves on our ability to provide the highest quality PCBs in the industry, and each of our rigid flex PCBs undergoes rigorous quality assurance testing to ensure that they meet and exceed industry standards. Our sizable 55,000-square-foot manufacturing facility is centrally located in Minneapolis, Minnesota, a hotbed of flexible circuit experts and resources.