Hey guys,
So I bought a 12vdc coil relay by accident, when in fact i need a 4-5vdc relay to use with my arduino ( arduino.cc ), is there any way I could make this work?

Thanks,
-Falven

 

If you have a 12v supply available in your application, you could switch the ground side of the coil with an N-ch logic-level MOSFET or an NPN transistor, with a 470 Ohm resistor on the base.

Make sure to use a diode across the relay coil, or the coil current (reverse EMF) will blast the MOSFET/transistor when the Arduino shuts it off. The cathode of the diode (banded end) goes towards +12v. Any 1N400x series diode should work fine.

 

Thanks a ton, trying this now, will post back