ABSTRACT
This chapter concentrates on the simplest semiconductor device—the diode—which has one basic property: it conducts current much more easily in one direction compared to the other. This depends above all on the properties of pn junctions, which are junctions between two different types of semiconductor formed within a single crystal. The chapter describes the manufacture and properties of pn junction diodes, as a first step towards understanding the structure and operation of more complex integrated circuits. It continues with a description of power supplies, particularly those which convert the a.c. mains into a stable D.C. voltage to power electronic circuits. Rectification is an important step in this, and is followed by smoothing and regulation. A pn junction is a junction, within a single crystal, between p-type silicon and n-type silicon. In other words the doping changes from primarily acceptors to primarily donors at a plane within the crystal.
