This publication was developed as a portion of a two-semester sequence commencing at either the sixth or the seventh term of the undergraduate program in electrical engineering at the University of Pittsburgh. The materials of the two courses, produced by a National Science Foundation grant, are concerned with power conversion systems comprising power electronic devices, electromechanical energy converters, and associated logic configurations necessary to cause the system to behave in a prescribed fashion. The emphasis in this portion (Part 2) of the two course sequence is on modeling power processing devices and circuits. This publication consists of five chapters which deal with: (1) power diodes; (2) thyristors, or silicon controlled rectifiers; (3) modeling a live-voltage commutated inverter; (4) thermal characteristics of materials; and (5) a free-wheeling diode DC motor drive. An appendix which provides a suggested guide for a time schedule of presentation of material is also included. (HM)