How did PCBs evolve to what they are today?

Latest update time：2022-11-01

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Like many other great inventions in history, the printed circuit board (PCB) as we know it today is built on advancements made throughout history. In our little corner of the world, we can trace the history of PCBs back over 130 years ago, when the world's great industrial machines were just beginning to move. What we will cover in this blog is not a complete history, but the key moments that transformed PCBs into what they are today.

Why PCB?

Over time, PCBs have evolved into a tool for optimizing the manufacturing of electronic products. What was once easily assembled by hand quickly gave way to microscopic components that required mechanical precision and efficiency. Take the two circuit boards shown in the figure below as an example. One is an old board used in calculators made in the 1960s. The other is a typical high-density motherboard you'll see in today's computers.

PCB comparison between a 1968 calculator and today's modern motherboards

In a calculator we might have 30+ transistors, but on a single chip on a motherboard you'll find over a million transistors. The point is, the rate at which technology and PCB design itself is advancing is impressive. Now, everything on a calculator PCB can fit into a single chip of today's designs. This brings attention to several notable trends in PCB manufacturing:

We are integrating more functionality into advanced devices such as integrated circuits (ICs) and microprocessors.
We are shrinking passive components such as resistors and capacitors to the microscopic level.
All of this has led to an increase in component density and complexity on our circuit boards.

All of this progress is driven primarily by increases in the speed and functionality of our products. We expect our devices to respond instantly, and even a few seconds of delay can drive us crazy. For functionality, think about video games. Back in the 80s, you were likely playing Pac-Man in an arcade. Now we’re seeing photorealistic representations of reality. The progress is simply insane.

Today, video game visuals are almost photorealistic.

It’s clear that the development of PCBs is a direct response to our expectations of our devices. We need faster, cheaper, more powerful products, and the only way to meet these demands is to miniaturize the manufacturing process and make it more efficient. When did this craze for electronics and PCBs begin? At the dawn of the Gilded Age.

Gilded Age (1879 – 1900)

We ended the Civil War in the 60s and now the manufacturing industry in the United States is booming. During this time, we are taking everything we can from food to clothing, furniture, and railroad tracks. Transportation is taking off in a big way and our greatest engineers are figuring out how to get someone from coast to coast in 5 to 7 days instead of 5 to 7 months.

Railroads made traveling from coast to coast a matter of days instead of months.

During this period we also introduced electricity into homes, starting first in cities and then moving into suburban and rural areas. Electricity is now an alternative to coal, wood and oil. Think about living in New York in the dead of winter and trying to cook or heat with dirty coals or piles of firewood. Electricity changed all that.

An interesting point is that Standard Oil, which had a monopoly on the oil market, did not supply oil for gasoline. Their market was oil for cooking, frying, and lighting. With the advent of electricity, Standard Oil needed to define a new use for oil, which would come with the introduction of the automobile.

In May 1878, Standard Oil issued shares and the oil monopoly began.

During the Gilded Age, we saw some great discoveries in electromagnetism. We invented the electric motor, which converts electrical energy into mechanical energy. We also saw the generator, which does the opposite by converting mechanical energy into electrical energy.

This was also a period of talented inventors who still have an impact on our electronic world today, including:

Thomas Edison invented the light bulb in 1879 and motion pictures in 1889, among many other innovations.
Nikola Tesla invented the electric motor in 1888 and AC power in 1895.
Alexander Graham Bell invented the telephone in 1876.
George Eastman's Kodak invented the first consumer camera in 1884.
Herman Hollerith invented the tabulating machine in 1890 and later founded IBM.

One of the biggest debates during this period of intense innovation is that between AC and DC. Tesla's alternating current eventually became the ideal method for transmitting electricity over long distances. Interestingly, however, we are still dealing with AC-DC conversion today.

Alternating current may have won the battle, but direct current still dominates electronics.

Look at any electronic device you plug into the wall, you'll need to convert AC to DC. Or if you look at the infrastructure required for solar panels, they produce electricity in DC, which must be converted back to AC as a power source, and then converted back to DC for use by our devices. You could almost say that the AC-DC debate never ended, that a balance had just been struck between the two opposing ideas.

There is a lot of back and forth between AC and DC in solar panels.

Note that the original idea of PCBs was not invented during the Gilded Age. However, without the manufacturing capabilities of this era, and the widespread influence of electricity, PCBs would never have become what they are today.

Progressive Era (1890 – 1920)

The Progressive Era was marked by a period of social reform, with legislation like the Sherman Antitrust Act breaking up Standard Oil's monopoly. This is also when we see the first PCB patent. In 1903, German inventor Albert Hanson applied for a British patent for a device described as a flat foil conductor on a multilayer insulating board. Sound familiar?

Drawing depicting Albert Hanson's first PCB patent.

Hansen also described the concept of via applications in his patent. Here he showed that you can punch a hole through two layers with perpendicular lines to create an electrical connection.

During this time, we begin to see a major push by Edison and other business leaders to get electric devices into everyday homes. The problem with this push was a complete lack of standardization. If you lived in New York or New Jersey and used Edison's electric inventions for lighting, heating, or cooking, what would happen if you used them in another city? They wouldn't work because each town had its own configuration of outlets.

The problem was also made worse by the fact that Edison didn't just want to sell people a light bulb, he wanted to sell a service. Edison could provide you with electrical service on a monthly basis; you would then buy light bulbs, appliances, etc. Of course, none of these services are compatible with other competing methods.

We have Harvey Hubbel to thank for finally ending this chaos. In 1915, he patented the standard wall socket plug that is still in use today. Now we don't have a toaster or heating plate plugged into a light bulb socket. This is a huge win for industry standardization.

Thanks to Harvey Hubbel, we now have a standardized wall outlet for all electronic devices.

Finally, it is important to note that the Progressive Era marked the beginning of World War I. This conflict was purely focused on mechanical devices and trench warfare. PCB concepts, and even basic electronics, were not yet used in military applications, but they soon would be.

Roaring Twenties (1920s)

With the end of World War I, we are now in the Roaring Twenties and see a huge boom in the American economy. For the first time in history, more people live in cities than live on farms. We also begin to see the introduction of chain stores and brands across the United States. You might have one or two family-owned stores in two different towns, but now we have major brands and stores that go national.

The greatest invention of this period was Henry Ford’s car and the infrastructure it required. This situation is similar to the 1990s when we had to build a major infrastructure to handle the Internet and our information age by building switches, routers, and fiber optic cables. The car is no exception.

Henry Ford's first car - the quadricycle.

Here we see what was once a dirt road being paved. People needed gasoline to power their vehicles, so gas stations came into being. You also have a repair shop, accessories, and more. Many people's entire lifestyles stemmed from the invention of the automobile, and still do today.

It was also during this time that we saw the introduction of modern appliances that we still rely on today, such as washing machines, vacuum cleaners, and refrigerators. This was the first time that people were able to buy perishable goods in stores and store them to extend their freshness.

But where are our PCBs? We still haven't seen them used in any appliances or cars launched during this period. However, in 1925, Charles Ducasse filed a patent that described a process for adding conductive ink to insulating materials. This will later produce a Printed Wiring Board (PWB). This patent is the first practical application of something like a PCB, but only as a flat heating coil. We haven't gotten any actual electrical connections between the board and the components, but we're getting close.

PCBs continued to evolve, this time being used as heating coils for Charles Ducas.

Great Depression (1930s)

In 1929, the stock market crashed, taking with it all the great innovations of our time. Here we see a period when unemployment exceeded 25%, 25,000 banks failed, and massive hardship spread across the globe. This was a tragic time for humanity as a whole, paving the way for the rise of Hitler, Mussolini, Stalin, and future conflicts in our world. Until now, PCBs may have been silent, but that's all about to change.

The Great Depression affected everyone from banks to ordinary workers.

World War II (1939 – 1945)

World War II was ongoing, and the United States entered the fight after the bombing of Pearl Harbor in 1942. What’s interesting about Pearl Harbor is the entire communications failure that led to the attack. The United States had good evidence that a crisis was imminent, but all attempts to contact their military base in Honolulu had been unsuccessful, leaving the island unprepared.

A battleship lost in the attack on Pearl Harbor.

As a result of this failure, the U.S. Department of Defense realized they needed a more reliable method of communicating. This brought electronics to the forefront as the primary means of communication to replace Morse code.

It was also during World War II that we saw the first use of PCBs in what we know today as proximity fuses. The device was used for high-velocity artillery shells that needed to be accurately fired at long distances in the sky or on land. The proximity fuse was originally developed by the British to counter the advance of Hitler's army. It was later shared with the United States who perfected the design and manufacturing.

One of the earliest military applications using PCBs was the proximity fuse.

During this time we also had Paul Eisler, an Austrian living in the UK, who patented copper foil on a non-conductive glass substrate. Sound familiar? This is the concept we still use today to make PCBs with insulating layers and copper on the top/bottom. Eisler took the idea a step further by making a radio with his PCB in 1943, which would pave the way for future military applications.

Radio built by Paul Eisler from the first printed circuit board (PCB).

Baby Boomers (1940s)

As World War II drew to a close, we saw our soldiers come home, start families, and have tons of kids. Cue the Baby Boomers. It was during the post-war era that we saw a ton of improvements to existing appliances like vacuum cleaners, washing machines, televisions, and radios. Now that the Great Depression was over, many consumers could finally afford these appliances for their homes.

We still haven't seen consumer grade PCBs. Where are Paul Eisler's works? Take a look at the old TV below and you'll see all the components, but none of the underlying PCB foundation.

An old Motorola TV set from 1948, no PCB.

Despite the lack of PCBs, we did see the arrival of the transistor at Bell Labs in 1947. It would be another six years in 1953 before the device was finally used in production, but why so long? In those days, information was disseminated through journals, conferences, etc. Before , the dissemination of information simply took time to spread.

The first transistor was invented at Bell Labs in 1947.

Cold War Era (1947 – 1991)

The advent of the Cold War era marked a considerable period of tension between the United States and the Soviet Union. The two giants almost went to war with each other due to their differences between capitalism and communism, and put the world under the threat of nuclear destruction.

To stay ahead in this arms race, both sides must improve their communication capabilities to understand what the enemy is doing. Here we see the PCB being used to its full potential. In 1956, the U.S. Army published a patent for a "circuit assembly process." Manufacturers now have a way to both secure electronics and create connections between components with copper traces.

As PCBs began to take off in the manufacturing world, we found ourselves participating in the world's first space race. Russia achieved some amazing achievements during this period, including:

1957 Sputnik, the first artificial satellite, is launched
Launched the first spacecraft to the moon in 1959, Luna 2
1961 Sends first cosmonaut Yuri Gagarin to orbit the Earth

Sputnik, Russia's first artificial satellite, was launched in 1957.

Where is America in all this? Mainly lagging behind, usually taking a year or two to develop the same technology. Against this disparity, we see a five-fold increase in the U.S. space budget in 1960. We also have the famous 1962 President Kennedy speech, part of which is worth quoting below:

"We choose to go to the Moon! We choose to go to the Moon in this decade over other things, not because they are easy, but because they are hard; because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one we are willing to accept, one we are unwilling to postpone, and one we intend to win." -- John F. Kennedy, President of the United States, September 12, 1962

All of this led to a landmark moment in history: On July 20, 1969, the first American walked on the moon.

The first man to land on the moon, a historic moment for mankind.

Back to PCBs, in 1963 we had Hazeltyne Corporation patent the first plated through hole technology. This will allow components to be placed closely together on the PCB without having to worry about cross-connections. We are also seeing the introduction of surface mount technology (SMT) developed by IBM. These dense components found their first practical use in a Saturn rocket booster.

1967 The first through-hole PCB technology patented.

The dawn of the microprocessor (1970s)

The 1970s brought us the first microprocessors in the form of integrated circuits (ICs). This was originally developed in 1958 by Jack Kilby of Texas Instruments. Kilby was new to TI, so his innovative ideas for ICs were largely kept secret. However, when TI's top engineers were sent away for a week of meetings, Kilby was left running with the ideas in his head. Here he developed the first IC in the TI labs, and the returning engineers loved it.

Jack Kilby holds the first integrated circuit.

In the 1970s we saw the first use of ICs in electronics manufacturing. By this time, if you weren't using a PCB to make connections, you were in big trouble.

The Dawn of the Digital Age (1980s)

The digital age has brought about dramatic changes in the media we consume, introducing personal devices such as compact discs, VHS, cameras, game consoles, Walkmans, and more.

In 1980, the Atari video game console made a child’s dream come true.

It is important to note that PCBs were still drawn by hand using light boards and stencils, but then computers and EDA came along. Here we see EDA software like Protel and EAGLE revolutionize the way we design and manufacture electronics. Now, instead of a photograph of a PCB, we can save our designs as Gerber text files, whose coordinates can be fed into manufacturing machinery to produce the PCB.

Printed circuit boards were drawn with tape and mylar before EDA arrived.

Internet Era (1990s)

In the 1990s, with the introduction of BGAs, we saw the use of silicon in full swing. Now we can put more gates on a single chip and start embedding memories and systems on chips (SoCs) together. This was also a period when electronic products were highly miniaturized. We didn't see any new features being added to the PCB, but the entire design process started to change and evolve, moving toward ICs.

Designers now must implement design-for-test (DFT) strategies into their layouts. It's not easy to pop out a component and add a blue line. Engineers must design their layouts with the perspective of future rework. Are all of these components placed in a way that they can be easily removed? This is a huge concern.

This was also an era when smaller component packages like the 0402 made hand soldering of circuit boards nearly impossible. The designer now lives in his EDA software, and the manufacturer is responsible for physical production and assembly.

Surface mount components from large to small.

The Hybrid Era (2000s and Beyond)

Cut to the current era of electronics and PCB design; we call it the hybrid era. In the past, we had a variety of devices to meet a variety of needs. You need a calculator; you buy a calculator. You want to play video games; you buy a video game console. Now you can buy a smartphone and get 30 different levels of built-in functionality. This may seem very obvious, but when you actually see all the things our smartphones can do, it's pretty astounding:

Gaming equipment	address book	e-mail	barcode scanner
flashlight	bell	camera	navigation
music player	schedule	video recorder	map
Internet browser	calendar	movie player	calculator
Telephone	notebook	Tickets	recorder
Answering machine	Short message	banking	books

We are in the age of equipment consolidation, but what comes next? PCBs are already established, and we have processes and procedures for almost everything. High-speed applications are becoming the norm. We also see that only 25% of PCB designers are under the age of 45, while 75% are preparing to retire. The industry seems to be in a period of crisis.

Will robots be the future of PCB design? Maybe in a wearable device with flexible circuits? Or we might see protons replacing electrons with photonics. As for what we know about physical PCBs, that may even change in the future. No physical medium is required to enable the connection between components, instead there is the potential of wave technology. This would allow components to send signals wirelessly without the need for copper.

What does the future hold?

No one really knows where PCB design is going in the future, or even electronics in general. Nearly 130 years have passed since our manufacturing muscles began to turn. Since then, the world has changed forever with the introduction of major products such as cars, appliances, computers, smartphones, and more. Gone are the days when all our basic livelihoods and survival depended on coal, wood or oil. Now we have electronic gadgets that meet our daily needs.

But what does the future hold? That’s the big unknown. As we all know, every invention before us stands on the shoulders of its predecessors. Our ancestors brought PCB design to where it is today, and now it’s up to us to innovate and revolutionize the way we design and interact with technology. The future can be anything. The future depends on you.

Source: Electronic database

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