I have a Mega 2560 interfaced to a breadboard. The Mega is powered through the barrel jack, and the breadboard is powered using a 5V power supply connected to the power rails. I have connected the ground on the Mega and the breadboard together, so there is no float between the two.
The question is, should the +5 on each be connected? I can think of plausible sounding arguments either way.
Do not connect the two 5V supplies together,
If you provide barrel jack power the Mega's voltage regulator is active outputing 5V - two different 5V supplies will fight each other, possibly even oscillating and burning parts up.
You might be able to do away with the barrel jack supply and power the Mega from the 5V on the breadboard.
Thanks, I thought that might be the case. The voltage on the breadboard is dropping more than I would like, so I was hoping that load-sharing would be a thing.
I don't see where you identified the power source for the breadboard. What is it ?
5V power supply
isn't really much help.
Current rating for the P.S. might be nice..
raschemmel:
I don't see where you identified the power source for the breadboard. What is it ?
isn't really much help.Current rating for the P.S. might be nice..
For the original question, it didn't matter, I just wanted to know if the +ve side of two 5V power supplies could be hooked together.
The voltage drop problem is a separate thing, I'm still looking into it myself. I'll start a new thread if needed.