Polarity and direct current

[jabronyo]

Hi there. I have with me an old 12 volt AC (input) to DC (output) SHARP adaptor. It's currently configured to negative polarity but I'd want it to power a device that's set to positive polarity. Therefore, there's a mismatch.

I'd assume since it's direct current that I could simply switch the live and ground wiring. (Meaning i strip both wires of the device and the adaptor, but instead of connecting red to red, I connect the red to black)

I'm kinda cheap so buying a multi-purpose adaptor is currently out of my budget. (lol)
I don't want to short the whole thing though so I just want to ask you guys if this will work. :)

[Jaguarstrike]

Don't quote me on this, but so long as the power contacts have the proper voltage difference, then it shouldn't matter, since ground is arbitrary.

[phmeworp]

I don't want to short the whole thing though so I just want to ask you guys if this will work. :)

It will work. Just make sure you properly insulate the splices (tape, heat shrink tubing or such).

[jabronyo]

Oooh. Fuck. So the live wire's carrying a negative charge instead of a positive charge. The ground's just arbitrary. Guess I can't use it then.

I'd fry the device if I wired it directly to an alternating current, yes?

[phmeworp]

Oooh. Fuck. So the live wire's carrying a negative charge instead of a positive charge. The ground's just arbitrary. Guess I can't use it then.

I'd fry the device if I wired it directly to an alternating current, yes?

Dude! Let me try this again in English. You CAN use it, just as your original post indicated.

I am assuming that the gizmo you are dealing with is what we commonly call a wall-wart: a small cube with two prongs that plugs into a household electrical outlet with a pair of wires that go to a plug (two conductor).

There is no ground, per se; there is just a positive lead and a negative lead, both of which are isolated from any kind of 'ground'. You can change the effective polarity of the connector by cutting the wires and then reconnecting them in reverse... again, just like you described.

And yes, you stand a good change of damaging something by trying to run a DC powered device from an AC source. Most defininatley if you use the household AC power source directly. (think lound noises and smoke!)

[jabronyo]

Dude! Let me try this again in English. You CAN use it, just as your original post indicated.

I am assuming that the gizmo you are dealing with is what we commonly call a wall-wart: a small cube with two prongs that plugs into a household electrical outlet with a pair of wires that go to a plug (two conductor).

There is no ground, per se; there is just a positive lead and a negative lead, both of which are isolated from any kind of 'ground'. You can change the effective polarity of the connector by cutting the wires and then reconnecting them in reverse... again, just like you described.

And yes, you stand a good change of damaging something by trying to run a DC powered device from an AC source. Most defininatley if you use the household AC power source directly. (think lound noises and smoke!)

I see. Thanks!!!