For example, I have an antique portable television made by the Singer manufacturing company that plugs into US mains. However, it also has a 12v DC input and can run off of that. I also have a retro CCTV monitor that uses the same 120v mains plug and has a placard on the back that says it can use a 12V 12W battery. How is this possible? If an electronic device is designed to take 12v, wouldn’t 120v destroy the device? On the other hand, if a device is designed to accept 120v, shouldn’t 12v not be enough to operate it?
Edit: added a clarifying question
In: Physics
One of two things…
If the 120v plug is the big box, that transforms power to 12VDC @1A
Or…
The tv has internal components to transform 120VAC to 12VDC.
Take your phone charger for example, you’re not sending 120VAC to your phone, you’re sending 5VDC
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