A circuit board is a piece of insulation that is threaded with conductive wires and similar components. When a power supply introduces an electrical charge to the board, it is distributed along these wires to different components in a variety of ways. This lets the board control how these components are activated and charged during the use of an electrical device. A wide range of devices include at least one circuit board, including mobile phones, computers, and digital watches.
Also known as Printed Circuit Boards (PCB), they consist of an insulator, usually fiberglass, with threads of conductive material acting as wires on the base of the board. The insulator may consist of one or numerous layers of material glued into a single piece. These additional layers can serve a number of purposes, including grounding the board or providing heat resistance. 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.
Components and Design
Since the 1980s most circuit boards use surface-mounted components, which are designed with small tabs, and easily soldered into place on the board. Modern circuit board producers often perform this process by placing the cool solder mixture, and baking the entire board to melt the solder and set the components in place. Prior to the creation of surface-mount technology in the mid-1960s, manufacturers used wire to attach components to each circuit board. With the need for wire eliminated, boards have become lighter and more efficient to produce.
A number of additional technologies may be applied to circuit boards for specialized uses. Flex boards, for example, are designed to be quite flexible, allowing placement of the circuit board in positions which would otherwise be impractical. Some companies design boards for use in satellites and spacecraft, making them with rigid copper cores that conduct heat away from sensitive components to protect them in extreme temperatures. Other manufacturers make circuit boards with an interior conductive layer to carry power to various components without extra traces or wires.
Invention and History
Although previous inventors had developed similar boards in the first decade of the 20th Century, Austrian engineer Paul Eisler created the first printed circuit boards in the mid-1930s. During World War II, the US produced them on a massive scale for use in war radios. This hardware remained primarily confined to the military sector during this period, but following the end of the war it became available for widespread commercial use.