Some new formulas for reactance coils

Formulas are presented and derived, which have not been previously published, for mutual inductance of coils with parallel axes, repulsion of coils with parallel axes, and self-inductance of long cylindrical coils. These formulas apply to practically all cases of reactance coils in common use. They are very convergent and accurate, and will give results to a given degree of accuracy with a minimum amount of labor. For many engineering problems, precise accuracy is not required, and sets of curves are given from which approximate readings may be taken.