I am making a two layer pcb, and I'm not sure where to keep the power and ground lines.

enter image description here. This is circuit is a design block. And in the pcb, there is going to be around such 20 design blocks. Power supply to the PCB is 24V. Max current consumed is around 4A.

I understand that is recommended to keep one plane as ground. And so I was wondering if it is okay to keep the other plane as power line. If not, what else can I do?

Any help would be appreciated. Thanks in advance.

  • \$\begingroup\$ What does the opto isolator bring to the party? \$\endgroup\$
    – Andy aka
    Commented Apr 14, 2020 at 7:59
  • 1
    \$\begingroup\$ It's there to blow up the FET gate with 24V. \$\endgroup\$
    – Justme
    Commented Apr 14, 2020 at 8:02

1 Answer 1


The bottom of the PCB should be a solid ground plane. On the Top Layer you can use either the complete plane as +24V, or use Polygons to make a 24V Layer. You can use a trace width calculator like this to find the required dimensions for current and voltage. Make sure you route away the high voltage from other components like mikrocontroller or logic elements.

P.S. The Circuit will destroy the mosfet. The gate of the IRFZ48 only works up to 20V, not 24V. You either have to select another mosfet, or use a zener diode to lower the voltage.


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