A comparison of the formulas for the calculation of the inductance of coils and spirals wound with wire of large cross section

Two methods have been used for the calculation of the inductance of coils of wire having a relatively large cross section. Of these, the summation method gives the inductance of the coil as the sum of the self-inductances of the turns and the mutual inductances of all. the pairs of turns. The Rosa method cal- culates the inductance of the equivalent current sheet as a first approximation to the inductance of the coil, and obtains the correction which must be applied by calculating (a) the differences between the self-inductance of the turns of wire and of the current sheet and (6) the differences of the mutual inductances of pairs of turns of wire and of the corresponding turns of the current sheet.