I am trying to power my Uno (rev 3) from a Dialight MDU-18 driver (http://www.dialight.com/Assets/Brochures_And_Catalogs/Illumination/MDEXU18V25100.pdf). Problem is that the Dialight supplies 33vDC and 350-700mA (under my control).
So I need to drop the 33vDC to 7-12vDC to feed into the Arduino's power jack socket. But I am unsure of the correct value and type of resistor to use. I've tried various calculations but have no confidence in my results.
Can anyone recommend a resistor value and type?
Many thanks, Mark