This document provides an overview of power electronic devices. It begins with an introduction to power electronic devices and their features. It then discusses uncontrolled devices like power diodes and their characteristics. It covers half-controlled devices like thyristors and their operation. Fully-controlled devices like GTOs, IGBTs, MOSFETs are described along with their structures, characteristics and examples. The document concludes with emerging devices like SITs, SITHs, MCTs and IGCTs.