The Wound Foil Inductor is an important example of inductive components with appreciable internal capacitance. It is examined from three viewpoints – electromagnetic field theory, distributed-parameter (or transmission-line), and lumped equivalent circuit. The analyses are compared, particularly in terms of phase gradients within a component, and the relationship between a two-dimensional field analysis and the now established lumped model is derived.
The Biot-Savart law gives the velocity associated with an elemental portion of line vortex, or the magnetic field associated with an elemental portion of line current. The following proof may appeal to students who approach fluid mechanics or electromagnetic-field theory from the engineering viewpoint. It will be stated in terms of fluid mechanics.
Consider a very small length δs of line vortex of circulation strength Γ. At P(x) the velocity δV associated with this portion depends on
Γ δs and x.
A method for computing surge impedance of transmission line tower by electromagnetic field theory.
