Quick question about wall adapters

[Radamus]

I know this is really simple, but I've been looking all over the place and I can't find an answer. Does a 12v AC wall adapter go from -12volts to 12volts, or do I need a 24v for that?

Looking to build a simple power supply, and I can't remember how this works. Sorry if this has been asked, but I've searched.

Thanks in advance.

[zyxwyvu]

12VAC usually means 12V RMS (http://en.wikipedia.org/wiki/Root_mean_square). This means the voltage goes between -16.9V and 16.9V.

[Radamus]

Thanks for the response. I knew it would be simple, I just couldn't figure out where to look.