Difference Between the Partial Self-Inductance at DC and at HF

The difference of the partial self-inductance of a single conductor is determined between two extremes of the frequency range: at dc and at HF (infinite frequency). They are first calculated separately for a finite large length. Both contain the same logarithm(length) singularity, but this disappears in their difference, which only involves the logarithm of the ratio of the equivalent radius and the geometrical mean distance. We have applied this to some common conductor cross sections: circle, ellipse, rectangle, and diamond and to the limit of zero thickness of these cross sections. In the latter case, a general expression is derived.