<snip> Smitty says: What does r have to do with watts. I thought it was E x I <unsnip> Use the rest of the ohm's law equations, E=I*R I=E/R R=E/I. In the equation P=E*I substitute I*R for the E and you get P= I*R*I or P=I2R or substitute E/R for the I and you get P= E*E/R or P=E2/R Although I think you jest... Frank DuVal