Hi there,the only measurements that I know of are,R.M.S. which means Root Means Square,or( True Power,or Constant Power),Peak Power,and Peak to Peak Power,sometimes refered to as Music Power.A watt is a watt,most of Europe runs on higher AC voltages than we do over here,but a volt is a volt,they just run on 220,240,260 as opposed to 120,if you double the voltage,you will draw half the current,which for the power company means smaller gague wire can be used.Read up on OHM'S LAW and you'll find all the formulas and answers to your questions.Mel.