Printed Circuit Boards, or PCBs, are the panels on which the electronic circuit is placed. Older boards often reveal hand-drawn traces, which are much more fluid in design. With computerized PCB design, those lines straightened out. Most PCBs are made from FR4 (glass fiber and epoxy)[^fiberglass].
[^fiberglass]: Fiberglass is very strong, but can be sawn through. When sawing, make sure you wear the right protection, microfibers can end up anywhere.
The copper tracks on a PCB are usually covered with a green protective layer, known as solder mask. Sand this off and to expose the copper underneath, ready to solder onto again.
Most boards are labeled. They can include a date, information about connections, component numbering[^component-numbering], and sometimes even their their values [^monotron].
Not all PCBs follow the industrial template. Artists and other tinkerers have come up with alternatives: the paper circuits of Ciat-Lonbarde, or Dirty Electronics’ boards made from wood and nails. For our circuits, these approaches are ideal—still flexible, still open to change.
[^component-numbering]: The schematic contains references to the component number, helping with debugging.
[^monotron]: Some devices take this idea further. The Korg Monotron includes extra patch points directly on the board for DIY mods and expansions.
