How to get 12 volt AC?

[Stingray]

Someone recently gave me this plastic traffic light, which is a bit cheesy, but I thought it might be kind of cool in the game room. It didn't have a power adapter, I saw 12 volt on the back and thought I surely have a 12 volt power brick that I can use to power it. Once I got it home I noticed that it was 12 volt AC, and not DC. Anyone know where I can get a 12 volt AC power brick, or is there something simple I can build myself to convert 120 volt AC to 12 volt?

-S

[whammoed]

Well, you could get a dc power brick and open it up.  It will either have a bridge rectifier or four diodes which you could remove and then wire the output leads directly.

Try at your own risk!

[Stingray]

Try at your own risk!

There's something about this bit that makes me somewhat reluctant.

-S

[whammoed]

don't blame ya, but its really pretty simple.  The four diodes or bridge rectifier (bridge rectifier is just four diodes hooked together in one casing) convert the ac to dc.  Take it out and you've got ac.  Take a look at the first pic in this post:
http://forum.arcadecontrols.com/index.php/topic,31413.0.html
the bridge rectifier is the black thing in the middle.  If I took it out and wired the leds directly it would be ac (and i'd burn out the leds)

[Gootfu]

Just an idea here,
How about using a doorbell transformer.  They step down 120v AC to 10-16Volts AC.  You can probably get one at a hardware store, you might even find a multi-tap one that will give you your 12volts.

[paigeoliver]

Did you try it with AC power? A lot of lights don't care if they get AC or DC.

[Stingray]

don't blame ya, but its really pretty simple.  The four diodes or bridge rectifier (bridge rectifier is just four diodes hooked together in one casing) convert the ac to dc.  Take it out and you've got ac.  Take a look at the first pic in this post:
http://forum.arcadecontrols.com/index.php/topic,31413.0.html
the bridge rectifier is the black thing in the middle.  If I took it out and wired the leds directly it would be ac (and i'd burn out the leds)

Okay that actually doesn't sound too complicated (please feel free to carve that on my tombstone). I'll give it a go.

Did you try it with AC power? A lot of lights don't care if they get AC or DC.

I did try a 12 volt DC brick. No joy.

-S

[2600]

Do you know how much current you need?  You can get AC to AC bricks at RadioShack and such.

http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=273-1631

[Stingray]

Don't know. It isn't marked on the outside anywhere. I think I'll try hacking a DC brick before I go buy one of those Radio Shack AC-AC bricks. Hoping to get out cheap on this.

-S

[crashwg]

I'm fairly certain I have a 12v AC brick in my collection of random bricks that I have no idea what they go to.  If you pay for shipping I'll send it out to ya!

[danny_galaga]

pretty much as they say, you can hack a power supply. but bear in mind the voltage will be different so you will have to hack a different voltage supply. ive forgotten now how to work it out (my memory is telling me a 6v dc supply will give you 12v ac but im not sure now). anyway the other way is to just buy a small 120v-12v transformer from an electronics store. two wires in, two wires out- nothing simpler!

edit: just make sure you wire it the right way around- i dont think 1200V will do your light much good (",)