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INTRODUCTION

The concept of *inductance* is simple and straightforward. However, actual computation of the inductance of various physical structures and its implementation in an electric circuit model of that structure is often fraught with misconceptions and mistakes that prevent its correct calculation and use. This book is intended to ensure the correct understanding, calculation, and implementation of inductance.

1.1 HISTORICAL BACKGROUND

Knowledge of magnetism has a long history [3]. A type of iron ore called *lodestone* had been discovered in Magnesia in Asia. This material had some interesting properties of magnetic attraction at a distance of other ferromagnetic substances and was known to Plato and Socrates. In the sixteenth century, William Gilbert first postulated that Earth was a giant spherical magnet, and A. Kirchner, in the seventeenth century, demonstrated that the two poles of a magnet have equal strength. Pierre de Marricourt constructed a compass in 1629 that allowed the determination of the direction of the North Pole of the Earth. In 1750, John Mitchell determined the universal principle that force at a distance depends on the inverse square of the distance. At the beginning of the nineteenth century, Alessandro Volta developed a battery (called a *pile).* This allowed the production of a current in a conducting material such as a wire. In 1820, Hans Christian Oersted showed that a current in a wire caused the needle of a compass to deflect. Around the same time, ...