Even though they aren’t often seen, circuit boards are present in just about every piece of technology used in the modern world. Sure, they are a part of computers and phones, but they are also built into refrigerators, thermostats, cars, and garage door openers. If it has a screen or uses power, it is likely that there is a circuit board or two tucked away inside. Originally built by hand, huge strides in technology were made after Paul Eisler invented the printed circuit board (PCB) in 1936. He used it as a part of the radio he designed and built in 1942. This small piece of technology has been the basis on which all modern tech is built.
Since the 1940s, printed circuit boards have been used to advance technology to a place that might seem like science fiction to Eisler. Pick and place machines, coincidentally also powered by circuit boards, are used to build those same boards in a much faster time frame.
These boards are used to connect electronic components together. The boards are inlaid with conductive pads and tracks of metal that allow the energy to flow between them. A large-scale example of this would be to observe power lines. If the earth was thought of like a giant circuit board, the power lines and transformers are the conductive pieces on the board. PCBs work much the same way but on a much smaller scale.
With build-your-own kits available for both adults and children, anyone can get into designing their own components or even building small devices. Learning the basics of circuitry and electronics would allow a person to build their own radio just like Paul Eisler did. This technology is constantly advancing and shrinking. It is easier than ever to bring new designs to the market or even just to the kitchen table.