Junction Transistors explains the operation and characterization of junction transistors to a point from which detailed circuit analysis and design can be undertaken. This book highlights three features. First, this text analyzes the behavior of semiconductors, pn junctions, and all types of bipolar transistors from the standpoint of classical physics. The validity of this approach and the link with quantum physics is discussed in an appendix. Second, the high-speed operation of transistors is analyzed and explained in terms of base charge. Finally, the analysis of transistor behavior in terms of the movements of holes and electrons can only be carried out explicitly with the aid of simplifying assumptions, not all of which can be fully justified. In this selection, an attempt has been made to justify these assumptions wherever possible, to show where they break down, and to remove the assumptions altogether in one or two instances and obtain more rigorous solutions. This publication provides material of interest not only to undergraduates but also to those more familiar with the properties and use of transistors.