This is the kind of relay that take 220V AC to activate the circuit. This is not a DC activated relay.
This is why I am asking. I am looking to make a circuit that will activate/deactivate a relay or switch in response to a general AC power failure. I wish to activate a DC battery operated light probably at 9 Volt DC.
I am also considering using a 5 volt DC relay powered via an AC wall USB charger.