my power grid is 220v 50hz but i get 175-200v, If I insert any cd in my desktop pc and the cd rom starts spining hard, the pc turns off. it is obvious that my power supply is not giving enough power for every thing in the pc to work properly. i have tried it with an AVR and the whole ting worked fine. I need your help in building a small step up transformer that will boost my AC inptut from 180 to 220V. how do i calculate the turns and wire guage for this self induction transformer ?