Page 60 - Make Your Own PCBs with EAGLE from Schematic Designs to Finished Boards

CHAPTER 3

Components and Libraries

F inding the right components for a project can be a time-consuming process. If you are using

EAGLE, then a further complication is that you need to either use components that are already
in the EAGLE libraries or download a library that includes the part or, as a final resort, create your

own part and add it to a library. This chapter serves as a reference for the most common components
that are used by hobbyists, as well as showing you where to find EAGLE models for components and
even the components themselves.

U.S. versus European Circuit Symbols

When you are choosing a component from a library to use in a schematic, the most important thing
about it relates more to the board layout than to the schematic. If it does not have pads in the right
places, then it will not be of any use. Another consideration is how the symbol is drawn on the

schematic. Unfortunately, there is more than one standard for component symbols in use. The main
divide is between symbols commonly used in the United States and those in use in Europe.
If you browse through the libraries, you will often find two versions of each component. For

example, R-EU and R-US for European and U.S. resistor symbols. Figure 3-1 shows the symbols for
resistors and capacitors.