Printed circuit board
The main task in designing a PCB is figuring out where all the components are going to go. Normally there is a design or schematic that will be turned into a PCB. There is no such thing as a standard printed circuit board. Each board is designed for its own use and must be the right size to fit the required space. Board designers use computer-aided design software to layout the circuit designs on the board. The spaces between electrical paths can be 0.04 inches (1.0 mm) or smaller. The location of the holes for component leads or contact points are also laid out. Once the circuit pattern is laid out, a negative image is printed out at exact size on a clear plastic sheet. With a negative image, the areas that are not part of the circuit pattern are shown in black and the circuit pattern is shown as clear. The metal is then removed from the clear areas, usually with chemicals. This design is made into instructions for a computer-controlled drilling machine or for the automatic solder paste used in the manufacturing process.