Slide Presentations for ECE 329, Introduction to Electromagnetic Fields, to supplement “Elements of Engineering Electromagnetics, Sixth Edition” by Nannapaneni Narayana Rao Edward C. Jordan Professor of Electrical and Computer Engineering University of Illinois at Urbana-Champaign, Urbana, Illinois, USA Distinguished Amrita Professor of Engineering Amrita Vishwa Vidyapeetham, Coimbatore, Tamil Nadu, India
Ampére’s Circuital Law 2.4 Ampére’s Circuital Law
Ampére’s Circuital Law
= Magnetomotive force (only by analogy with electromotive force), = Current due to flow of charges crossing S, = Displacement flux, or electric flux, crossing S,
= Time rate of increase of displacement flux crossing S, or, displacement current crossing S, Right-hand screw rule. Any surface S bounded by C, but the same surface for both terms on the right side.
Three cases fo clarify Ampére’s circuital law (a) Infinitely long, current carrying wire No displacement flux
(b) Capacitor circuit (neglect fringing of field in the capacitor)
(c) Finitely long wire
Uniqueness of
Displacement current emanating from a closed surface = – (current due to flow of charges emanating from the same closed surface)
D2.9 (a) Current flowing from Q2 to Q3.
(b) Displacement current emanating from the spherical surface of radius 0.1 m and centered at Q1. (c) Displacement current emanating from the spherical surface of radius 0.1 m and centered at Q3.
Interdependence of Time-Varying Electric and Magnetic Fields
Hertzian Dipole