I am using 7805 regulator from 12V source to power a modem. Current drain is about 500 mA. I also want to use a AC adapter (5V 1 Ampere model) at the same time. In other words when there is a electricity modem gets its voltage from AC adapter and during outage it gets from 12V battery via 7805 regulator.
So I am thinking of simply hooking the AC adapter in parallel with 7805 output. Would that be a wise move? Thanks.
I would appreciate if you can explain in terms of how I connect the diodes and where. Is this required to protect the battery from getting voltage from adapter? Thanks.
I would appreciate if you can explain in terms of how I connect the diodes and where. Is this required to protect the battery from getting voltage from adapter? Thanks.
Another idea would be to put a suitable resistor in parallelwith D2 in MikeMLs circuit and trickle charge the battery to ensure it is always fully charged.
I forgot to say that, if a 6V battery is used, the diode in series with the battery would need to be a Schottky, otherwise the voltage drop will be far too great.