really noob question..
I am thinking of using a 12v power source and a 5v power source as an external power supply for my 5v relay (and some other stuff that I might add up to my project that will need 5V) and the 12v is for my 12V solenoids. Is it right to connect all ground wires to the ground of the Arduino? I am really sorry that I have to ask this question cause all tutorials I see online are only connecting one external power supply to their Arduino.
Any form of correction is highly appreciated. Thank you so much