The focus of this book is the physical modeling of mechatronic sensors and actuators and their precise numerical simulation using the Finite Element Method (FEM). It is complete in the sense that it discusses the physical modeling as well as numerical computation. In addition, a comprehensive introduction to finite elements, including their computer implementation, is given. Furthermore, industrial applications motivates the reader with clear demonstrations the importance of numerical simulation for industry. A large part of the book describes the application of the developed numerical calculation schemes to industrial problems, e.g.: analysis and optimiztion of electrodynamic loudspeakers; acoustic emission of electric power transformers; and ultrasonic imaging system based on electrostatic micromachined transducers.