Can a 12V adopter be used for a 9V device?

Question

anonymous · Answer

Are you asking from a theoretical point of view or are you going to try it?

It's not the voltage that matters so much (+/- 3V isn't going to be a huge difference), but the current. If it is substantially more than whatever the device is meant to take, then it's certainly not advisable, as it will likely destroy it and could lead to injury/etc.

anonymous · Answer

$$P = VI$$
Power = Voltage x Current. Therefore it depends on the wattage of the 9 Volt power adapter that you're referring to in comparison to the wattage of the 12 Volt power adapter that you're trying to replace it with. As fewscrewsmissing says, depending upon that figure the amperage may change quite considerably. If the amperage is higher then it's more than likely that you will damage the device that you're trying to power.

anonymous · Answer

Got it.thanks