Yep, to take care of the quenching spike. Know about that. What I wasn't sure about is if the output was constant or pulses.David_AVD said:As long as you don't send values other than zero or 100% you shouldn't have an issue.
You will need a diode across the relay coil though. A 1N4004 (or 1N4007) with the cathode (banded end) towards the V+ terminal will do.