>> If PC power supply set to 110V and then plug it to 220V. Does PC power supply damage? I'm interested to know this because most of the power supply today are auto volt. I just want to know how well protected the PC power supply. << If the power supply has a select switch, then it's not auto volt. You should assume it will be damaged by 220V on the 110V setting. ******************************************************************** Olin Lathrop, embedded systems consultant in Littleton Massachusetts (978) 742-9014, olin@embedinc.com, http://www.embedinc.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.