On the Input coil there are two wire and Output coil there are 3 wire. 12v, 0v, 12v. if you connect both 12v wire then you get 24v ac line, and if 12v and 0v then get 12v AC line. You need to connect Rectifier circuit with this output to get dc voltage. This one good for up to 555 motor.
12-0-12 3a Transformer
This Package Include ---
1 Pcs 12-0-12 3amps Transformer
You get 3amps or even more from the transformer but not low. Best for making DC regulated Power Supply with LM317 IC.