Microelectronics has enabled designers of integrated circuits to exercise complete control over the electrical characteristics of each component they create. This unit will illustrate how such control is achieved and the various methods that can be applied in differing circumstances. This study unit is just one of many that can be found on LearningSpace, part of OpenLearn, a collection of open educational resources from The Open University. Published in ePub 2.0.1 format, some feature such as audio, video and linked PDF are not supported by all ePub readers.