Though boards are created in the first decade of the 20th Century, actually, the first PCB was created in the mid-1930s by an Austrian engineer Paul Eisler. During World War II, they were manufactured in a large scale for war radios in America, but PCBs became available for widespread commercial use after the war.
PCB structure has three parts, including an insulator, usually fiberglass, with threads of conductive material acting as wires on the base of the board. Threads on a circuit board surface are usually copper. The insulator may contain one or more layers which glued into a single piece, and additional layers are used to ground the board, provide heat resistance, etc.
Manufacturers had to use wire to connect components to each circuit board before the creation of surface-mount technology in the mid-1960s. Without using wires, printed circuit boards are much lighter and time-saved. After 20s’ development, most printed circuit boards used surface-mounted components in 1980s.
Modern printed circuit boards are able to apply various technologies, especially for those specialized one. For example, some companies design boards for satellite and spacecraft, making them with rigid copper cores that conduct heat away from sensitive components to protect them in extreme temperatures. Other may make boards with an interior conductive layer to carry power to various components without extra traces or wires.