The course will give basic principles of micro-electromechanical systems modelling. Starting from microsystem simple mechanical elements, the course will develop the modelling of more complex structures including electromechanical transducers. Approaches to reduced-order modelling of complex microstructures will be explained and the electromechanical and electroacoustic analogies will be studied in detail. Basic electromechanical transduction mechanisms will be described; their analogy models will be developed and applied to examples of real microsystems. Among the transduction mechanisms will be both reciprocal principles as electrostatic, piezoelectric, electromagnetic and electrodynamic, and non-reciprocal principles as piezoresistive and thermomechanical. Starting from microsystem basics, the course will give some principles of CAD of microsystem simulation and realated tools.