TABLE OF CONTENTS The development of new devices in the microelectronics industry has over the past 50 years been responsible for producing major changes in all industries. The technology developed has given cost-effective solutions and major improvements in all areas. The microprocessor is now a household word, and is embedded in every appliance, entertainment equipment, most toys, and every computer in the home. In the process control industry, processes and process control have been refined to a level only dreamed of a few years ago. The major new component is the microprocessor, but other innovations in the semiconductor industry have produced accurate sensors for measuring temperature, time, and light intensity; along with microelectromechanical devices for measuring pressure, acceleration, and vibration. This has certainly brought about a major revolution in the process control industry. Silicon has been the semiconductor of choice. Silicon devices have a good operating range ( ?50 to +150 C), a low leakage, and can be mass-produced with tight tolerances. The processing of silicon has been refined, so that many millions of devices can be integrated and produced on a single chip, which enables a complete electronic system to be made in a package. Several unique properties of silicon make it a good material for use in sensing physical parameters. Some of these properties are as follows:
The piezoresistive effect can be used in silicon for making strain gauges;
The Hall Effect or transistor structures can be used to measure magnetic field strength;
Linear parametric variation with temperature makes...
