This page is about using libraries with Eagle¹⁾ Cadsoft, a computer program which helps designing schematic diagrams (schematics) and circuit boards (pcb)²⁾.

During a design process it is sometimes necessary to add components which are not available in the ready supplied libraries. For this, components can be created manually and imported in the design. The method for this requires some fundamental understanding how components are organized in Eagle, both in the application itself as on disk. Guidelines about library design and recommendations how to use consistent nomenclature should help a user to successfully manage such collections of components, upgrade or extend them with other packages.

In the Control Panel within Eagle, library folders contain files with IC manufacturers, group of generic components or group specific symbols. Eagle treats each file as a library and it contains devices or device breeds³⁾. If it is available in Eagle and opened⁴⁾ one will observe that a selected device or device breed has primarily three entities:

• device: The real component, residing in a specific package with a specific symbol
• package: Footprint in the layout
• symbol: Drawing in the schematic

Each of these entities characterize a specific aspect of a component or component breed.

The default location for libraries which are created when installing Eagle, can be found when clicking on Options→Directories. On OSX, this is in $EAGLEDIR/lbr, where $EAGLEDIR represents the application installation directory from Eagle. Eagle recommends to keep this directory unchanged, as software updates may overwrite files in this folder.
Your own libraries should therefore be at another location. A suitable one would be in a subfolder within your Eagle projects folder like the following structure:

• $Home/Backup/eagle/
  • eagle_custom_libraries
    • dev_mylibrary1
    • dev_mylibrary2
  • eagle_projects
    • Arduino
    • PowerSupply
    • etc.

In order to make Eagle aware of the main custom libraries folder, just add the directory in Options→Directories. Any subfolders within this folder will be automatically used as well. For example:

$EAGLEDIR/lbr:$HOME/Backup/eagle/eagle_custom_libraries

While configuring the libraries folder, one could do something similar for the projects folder:

$HOME/Backup/eagle/eagle_projects:$EAGLEDIR/projects/examples

Definition Component breed
LM385 as an example. Create library dev_auditeon in the custom libraries directory:

.../eagle_custom_libraries/dev_auditeon.lbr

The device type LM386 contains one symbol and several packages. The symbol of the LM385 is:

%%<%%image here%%>%%

For each component within a component breed, Eagle designates a different package to a separate device. For example:

• LM385AYZ-2.5 (TO-92)
• LM385BXM-2.5 (SO-8)
• LM385M3-2.5 (SOT-23)

Describe library editor