Hi there! I have a transformer that has an input of two wires (120 vac) and an output of 15 vac in yellow colored wires. But there is also another, back wire output, that I don't really need, since I get my desired 15 vac, but just curious what is that for? I read somewhere that it is for the 'negative voltage' or somethhing. Can someone enlighten me please? Or a link to some page, cuz google didn't really come up with right results. (maybe i search wrong keywords).
Thanks much!!
Thanks much!!