Question on opto-isolators...
I would like to control 12V, 1A - 1.5A solenoids by switching a MOSFET with a 3.3V Arduino. I can use a IRLZ44N and do this directly since it is a logic level MOSFET.
However, I commonly see this type of circuit isolated with optocoupler/optoisolator. Is this unnecessary for my application? Attached to my Arduino I also have a GPS module and RF transceiver. Am I risking some kind of interference or noise by not using an opto-isolator on this circuit? Or is it more about risking a potential short circuit and avoiding a melt down?
Lastly, this project board will be going into a vehicle so both the 3.3V circuit and 12V circuit will share a common ground anyways. Does this defeat the purpose of the opto-isolator?