I saw a circuit on a website to make a backup battery circuit for a rechargeable 12v battery circuit.
However, I don't anticipate regular power outages, so I believe that one non-rechargeable 9v battery will last for more than the life of this project. I came up with the following circuit modeled after the first circuit (And a voltage regulator circuit I saw):
simulate this circuit – Schematic created using CircuitLab Is it dangerous to mix different voltages like this? I heard it could be for transformers, but what about a battery? Would the circuit only use the battery if the transformer is disconnected, and finally, does it look like it would work?