DigiKey has a ruler. See DigiKey part "PCB-RULER-ND". It's a PC board with examples of most of the common component footprints and some useful engineering data for PC board design. If you order enough stuff from DigiKey they send you one free. Otherwise it's US$4.95.
DigiKey has a ruler. See DigiKey part "PCB-RULER-ND". It's a PC board with examples of most of the common component footprints and some useful engineering data for PC board design. If you order enough stuff from DigiKey they send you one free. Otherwise it's US$4.95.