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48 DESIGN007 MAGAZINE I AUGUST 2024 In this column, I want to cover my experi- ences, particularly where costs are concerned, with printed circuit boards from the 1960s to the present day. I grew up in an apartment building in downtown Budapest, where I began doing hobby projects building circuits at our kitchen table. Now, I'm lecturing about the most recent advances in signal integrity at Oxford. We've come a long way. Over the decades, new technologies allowed users to have more layers, lower-loss dielectrics, fine- pitch surface connections, blind and buried vias, and HDI and HDI+ board constructions that allow us to design higher performing sys- tems. I expect this trend to continue. Today, to connect multiple components into a compact circuit, we mount the components on a printed circuit board. But in the late 19th and early 20th centuries, people would ham- An Evolution in PCB Design Costs mer nails into a wooden board and then wrap the leads of multiple components around them (the original breadboard). Household elec- tronics, like vacuum-tube radios, amplifiers, and record players, all used a similar concept. e connection between components was done with wires, which were easy to replace if needed, and allowed connections in any direc- tion. However, finding a particular wire in a chaotic three-dimensional wire blob was a real challenge. As the number of connections increased, so did the possibility of mis-wiring something and manufacturing also became time-consuming. e printed circuit board technology gradually emerged. (If you are interested in the history of printed circuit boards, see references 2 and 3.) In the 1960s and '70s, the main cost driver was the number of layers. Quiet Power Feature Column by Istvan Novak, SAMTEC Figure 1: A Philips B5X21A vacuum-tube radio with discrete wiring. You can see the front, middle (with the back removed), and back (with the cover removed and a jumble of wires and component leads). Fun fact: This radio still works even though it was manu- factured in 1963 1 .