The Resistance of Round-Wire Single-Layer Inductance Coils

Butterworth´s two formulae for the resistance of short coils with a finite number of turns and long coils with an infinite number of turns are merged into a single formula valid for coils of any length and having any number of turns. Numerical values of the functions appearing in the formula are given in tables. The formula is shown to give results in reasonable agreement with the experimental figures of Medhurst and Hickman.