circuit boards were created in the mid-1930s, most likely by Austrian Paul Eisler. During World War II the United States produced them on a massive scale for use in war radios. During this period the invention remained confined to the military sector, and it wasn’t until the end of the war that it became available for widespread commercial use.
Commonly known as PCBs (printed circuit boards), circuit boards consist of an insulator (usually fiberglass), with threads of conductive material serving as wires on the base of the board. The insulator may consist of one or numerous layers of material glued into a single entity. These additional layers may serve a number of purposes, including providing grounding to the board.
The threads on the surface of a circuit board are usually copper, created either by laying down individual lines mechanically, or by coating the entire board in copper and stripping away excess.
Since the 1980s most circuit boards use surface-mounted components. These components are designed with small tabs, and are made to be easily soldered in place on the board with very little hassle. In modern circuit board production, this process is usually performed by placing the cool solder mixture, and baking the entire board to melt the components in place. Prior to the creation of surface-mount technology in the mid-1960s, all printed circuit boards used wire to attach components to the board. With the need for wire eliminated, circuit boards have become lighter and more efficient to produce.
A number of additional technologies may be applied to circuit boards for specialized uses:
A· Flex circuit boards, for example, are designed to be quite flexible, allowing the circuit board to be placed in positions which would not otherwise be practical, or to be used in wire systems.
A· Circuit boards for use in satellites and spacecraft are designed with rigid copper cores to conduct heat away from the sensitive components and protect them in the extreme temperatures they experience.
A· Some circuit boards are designed with an interior conductive layer to carry power to various components without the need of extra traces.
