Need a 16 channel relay board. Looking on Ebay I see 5v and 12v.
Am I write in thinking that the 12v would need an external power supply for the relay coils and am I write in saying that the 5v relay board I can draw that right from the arduino for all 16 channels or do I need an external power supply for that as well
Thanks
Rick
You will need an external supply with either.
.
Thanks
Yes, separate, the 5V coils will need more current than the Arduino 5V can supply if you turn on more than a few.
A warning for 16-channel relay boards.
The ones I know have opto couplers, but are NOT optically isolated.
Not recommended for mains power applications.
Leo..
Ok thanks guys so I guess the boards are the same its what ever one I have a power supply for