Battery backup circuit

ktekx

I'm powering a 5v regulator from a wall adapter for a project but in the event of a power outtage, I would like the 5v regulator to automatically be switched to a 9v battery source. Can anybody suggest a simple circuit to do this automatic switching to backup power? I would like it if it used very little components (possibly an single IC?)

Bean

If the output from the wall adapter is greater than 9V, then you can just use two diodes. One from the wall adapter output to the regulator, and one from the 9V battery to the regulator.
Bean.

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ktekx

Thanks for the simple solution, Bean.