I need to make a correction 10^-6 is the proper factor in this equation. L = Ur ((Number of turns Squared)(Area of the Core's Diameter)/(Lenght of >Core))(1.26)(10^ -6 ) >Original Poster: BAREN01-at-aol-dot-com > > ><< >L = Ur ((Number of turns Squared)(Area of the Core's Diameter)/(Lenght of >Core))(1.26)(-10 to the 6) > >Ur = Greek symbol mu and = Permiability >(1.26) is a constant. >>> > > Is this equation for a sylinderical core? >Ramsey > >