The track size of any pcb is really important particularly when high currents are involved. Such a materia is strictly ruled by a lot of directives, almost always of military origins, not really important for a daily use.
All these directives (for people intereted in) are listed, public and published: here the link .
In an hobbystic environment such directives are not really important, what is really necessary is to follow some simple rules. Pcb are sold or realized normally into two different thickness: 35(micro)m and 70(micro)m. According to such a condition we can set the size according to the following table:
| Current (amp) |
width for 35um (mils) |
width for 70 um (mils) |
| 1 | 10 | 5 |
| 2 | 30 | 15 |
| 3 | 50 | 25 |
| 4 | 80 | 40 |
| 5 | 110 | 55 |
| 6 | 150 | 75 |
| 7 | 180 | 90 |
| 8 | 220 | 110 |
| 9 | 260 | 130 |
| 10 | 300 | 150 |
But what happens if, for instance, a big track must be connected from the bottom to the top layer? the secret consists in create simple pads to join the two tracks (top and bottom) in multiple points.
