Printed Circuit Board Explained — Everything You Need To Know

Four Facts about the Printed Circuit Board

• The first circuit board of any kind was invented in 1925 by Charles Ducas. It featured types of conductive material stencils over a wooden board.
• The inventor of the printed circuit board, Paul Eisler, inadvertently signed over PCB manufacturing and the patent rights to Technograph for one pound sterling and 16.5% ownership of the company.
• Telephone companies believed manual wiring was cheaper and more flexible than Printed Circuit Boards.
• The acronym, PCB, caused the Printed Circuit Board to be incorrectly associated in the public’s mind with polychlorinated biphenyl, an environmentally harmful chemical. The circuit boards were renamed printed wiring boards from the 1970s to the 1990s to avoid confusion.

Printed Circuit Board History

After Gustav Tauschek, another Viennese engineer and inventor, Paul Eisler, made a significant contribution to the modern electronics industry with the invention of the printed circuit board (PCB) in 1936.

Paul Eisler was born in Vienna in 1907. After graduating with an engineering degree from Technische Universität Wien (Vienna University of Technology) in 1930, already a budding inventor, he didn’t manage to find a job in Austria. In 1934, Eisler accepted a job in Belgrade, Yugoslavia to design a radio-electronic system for a train. He decided to leave that job when a customer offered payment in grain instead of currency.

Back in Austria, Eisler wrote for newspapers, founded a radio journal, and began to learn about printing technology. He started to imagine how manufacturers could use the printing process to lay down types of electronic circuits on an insulating base and do so in volume. At the time, it was usual to connect all components in electronic devices with hand-soldered wires, an error-prone method of manufacture that did not lend itself to any high degree of automation.

Eisler wanted to eliminate these problems, printing the wires on a board, and mounting the elements over it. In 1936 Eisler decided to leave Austria, in order to escape persecution from the Nazis. He secured an invitation to work in England based on two patent applications he had already filed: One for a graphical sound recording and one for a stereoscopic television with vertical resolution lines.

In London, he sold the TV patent for ₤250. It was enough money to stay for a while in a Hampstead boarding house, but he couldn’t find a job. He proceeded to develop his printed circuit board idea, which attracted the interest of a telephone company because it would eliminate bundles of wiring used for phone systems. They determined, however, that manual wiring work was cheaper and more flexible than PCBs.

As World War II loomed, Eisler worked on getting his family out of Austria. His sister committed suicide and when the war began, in 1940 the British interned him as an illegal alien. After being released in 1941, Eisler was able to find work in a music printing company—Henderson and Spalding.

Originally, his objective was to perfect the company’s unworkable Technograph music typewriter, operating out of a laboratory in a bombed-out building. Later, Technograph invested in his printed circuit idea (the concept of using etched foil to lay down traces on a substrate).

Unfortunately, Eisler forfeited rights to his invention when he neglected to read the contract before signing it, but it wasn’t the first or last time Eisler would be taken advantage of. It was a pretty standard employment contract in that he agreed to submit any patent right during his employment for a nominal fee (one pound sterling) but it also gave him 16.5 percent ownership of Technography, the manufacturers.

Eisler’s first PCB manufacturing assembly had almost no straight traces. He filed a patent application in 1943. Technograph drew no interest until the United States incorporated the technology into work on the proximity fuses of shells, which were vital to counter the German V-1 flying bomb. After that, Eisler had a job and a small amount of fame.

The technology spread after the war. The United States mandated in 1948 that all airborne instrument circuitry was to be printed. Eisler’s 1943 patent application was eventually split into three separate patents: 639111 (Three-Dimensional Printed Circuits), 639178 (Foil Technique of Printed Circuits), and 639179 (Powder Printing). These three were published on June 21, 1950, but very few companies actually licensed the patents, and Technograph had financial difficulties.

Eisler resigned from Technograph in 1957, to work as a freelancer. Some of the projects he created as a freelancer included films to heat floor and wall coverings and food, the foil battery, concrete molds, the pizza warmer and rear window defroster, and more. Eisler was not so successful in the commercialization of these components. Later, he found success in the medical field and had dozens of patents to his name at the time of his death.

Eisler’s PCB manufacturing and the invention of the etched foil printed circuit, while being of enormous benefit to the global electronics industry, brought him little personal financial return. Eisler died in London on October 26, 1992. He had just received the Institution of Electrical Engineers’ Nuffield Silver Medal.

Printed Circuit Board: How It Worked

The original PCB assembly technically performed the same tasks as modern circuit boards, but they were constructed in different ways and were far less advanced than modern components. The idea from Charles Ducas in 1925, to use an insulated substrate and conductive materials, was revolutionized by Paul Eisler.

Eisler took it one step further and created an etched foil-printed circuit board. This set the stage for mass production of circuit boards for manufacturers to use in a wide range of civilian and military technologies.

Printed Circuit Board: Historical Significance

Paul Eisler created the first PCB and started a timeline that stretches all the way to the present day. PCB technology continued to become more efficient and complex. This first patent led, over time, to types of multi-layered circuit boards, transistors, solder masks, and other technologies. While not financially successful in his lifetime, Eisler’s printed circuit board patent was an important moment in the history of computers.

The image featured at the top of this post is ©Georgi Dalakov / CC BY-SA 3.0, from Wikimedia Commons, the free media repository.