Im interested in building a stir plate for homebrewing but I have minimal knowledge of electrical wiring and I dont want to blow something up so I wanted guidance from experienced people. The basic build consists of a 12v pc fan, a toggle switch, a rheostat or potentiometer, and a power supply. I have been looking around my house and reading the stickers on some old power cables I have and I realize Im not sure exactly what I am looking for. I found an old cell phone plug that had DC on it and I figured that was probably not going to work as I was only dealing with AC. I have an old dvd player I need to throw out, can I just cut the cord on the back and use that?