I want to control a 5v 500mA pump from my Arduino.
I know that the Arduino cannot provide enough power for that, so I know I cannot use directly the Arduino output.
But I am wondering if it would be possible to connect the pump to external 5v source (the one powering the Arduino on +5v pin ) and to connect Arduino output to the pump ground. The pump will be powered from external source, and will be activated when setting output to LOW. Is this correct ? Or is it dangerous for the Arduino ?
If it is dangerous, I would be using a MOSFET, but I have absolutely no idea of the model I should use. I've heard about flyback diode but I didn't really understood how it works