Printed circuit boards were originally invented in 1936 by Austrian engineer Paul Eisler while working on a radio set. The PCB as it later became known, would revolutionize electronic circuit design and assembly a few decades later. By World War II they were secret technology being used in proximity fuses on bombs, mines, and other munitions by the U.S. military, resulting in a patent that remained classified for nearly forty years.
Providing connections to electrical components via paths etched in copper sheets and then laminated with non-conductive materials, this simple formula was arrived at through a combination of different applications by different scientists in the early 20th century.
The proximity fuse technology was released to the public after the war but it wasn’t until the 1950s when the U.S. Army devised the Auto-Sembly system, eliminating the need for multiple wire leads and reducing the connections to the board. Later advances in lamination and etching pioneered the electronics explosion that began in the 1980s. This was a crucial advancement in electronics, putting this invention in the pantheon of tech that changed the world.