Hi All. Not sure my question subject accurately describes what I am actually asking, but....what I want to do is this:
I have a circuit that runs off a fixed 5v source. By fixed I mean its a hard wired 5V adapter. What I want to do is have the circuit detect that this 5V source is gone, and it now needs to start running off a battery backup...which is also 5V. This is so when I turn off off the 5V hardwired source, the circuit will now run off the battery input.
Is this hard to do? What would I need to do?