ABSTRACT
This chapter begins with the basics of magnetic coupling, including the dot convention and the definitions of mutual inductance and the coupling coefficient. Magnetic coupling is the basis for transformer action and plays an essential role in many types of devices, circuits, and systems. The chapter introduces magnetic coupling between coils, whereby a time-varying magnetic field of a current-carrying coil induces a voltage in a nearby coil. It discusses the general method for analyzing circuits involving mutual inductance with emphasis on determining the polarity of the induced voltage. The chapter presents the T-equivalent circuit which eliminates the magnetic coupling and which can be used in analyzing most cases that are of practical interest. The general method of analyzing a circuit that includes a linear transformer is to apply Kirchhoff's voltage law in the meshes that include the magnetically coupled coils. Linearity implies superposition of all magnetic variables, including fluxes..
