INTRODUCTION Since World War II, no branch of science has contributed more to the development of the modern world thanelectronics.It has stimulated dramatic advances in the fields of communication, computing, consumer products, industrial automation, test and measurement, and healthcare. It has now become the largest single industry in the world, exceeding the automobile and oil industries, with annual sales of electronic systems greater than $2 trillion. One of the most important trends in this huge industry has been a gradual shift fromanalog electronicstodigital electronics.This movement began in the 1960s and is almost complete today. In fact, a recent statistic stated that, on average, 90% of the circuitry within electronic systems is now digital and only 10% is analog. This digitization of the electronics industry is merging sectors that were once separate. For example, two of the largest sectors or branches of electronics arecomputingandcommunications.Being able to communicate with each other using the common language of digital has enabled computers and communications to interlink so that computers can now function within communication-based networks, and communications networks can now function through computer-based systems. Industry experts call this mergingconvergence,and they predict that digital electronics will continue to unite the industry and stimulate progress in practically every field of human endeavor.Cook, Nigel P. is the author of 'Practical Digital Electronics', published 2003 under ISBN 9780131110601 and ISBN 0131110608.