These bulbs require a lot.
Can i use a 12v bulb in a 120v. Known as low voltage this voltage is acheived by stepping down reducingconverting standard 110120v high voltage into 12v low voltage with the aid of a transformer. You need a 12vdc LED with an A19 socket unless you plan to remove the existing socket. In some areas of the country the local code requires a low voltage 12V light while in other areas it is fine to use a 120V light.
But one that didnt use a lot of power. As n7bsn said its quite possible to use a 120v fixture with 12V bulbs of the appropriate type at least in most cases. As for running regular household lightbulbs on 12v DC it CANT be done.
The notable difference is that bulbs intended to operate at 120v have a thinner insulator between the tip and the shell the minimum insulator height for E26 lamps bulbs is 325mm and for E27 is 5mm. Im guessing since the fixture has been water exposed for so long I. You can put a 120v bulb in a 240 v circuit and it will flash brightly as it burns out.
If you search 12v Edison light bulbs on Amazon youll find some that will give you a better idea of what they are. Based on some personal lighting trials I use 450 more or less lumen 120 volt LED bulbs because they use less energy and provide adequate for me light normally the bulb packaging specs range between 5 and 7 watts and the actual current typically ranges between 6 and 8 amps including a small inverter normally the dimmable bulbs have been. You can either replace it with a unit that has an integrated switch or you can add one yourself.
You can use a 240 v bulb I am assuming filiment bulbs in a 120v circuit but it will barely glow for any brightness it needs to be near its rated voltage. They are cheap and can be found at most hardware stores. Id think it would it would just not be nearly as bright and wife says it was never very bright I dont remember.
Insert the DC output hardwired from the breaker service panel exclusive for the E27 ceiling lights or outlets for E27 luminaires. A 120-volt light bulb can typically be screwed into an indoor light fixture and operate correctly without further complication. I found these at LOWES for under 10 and decided it was time to hack.

