Sensors and Amplifiers

Abstract

Sensors are electrical-mechanical elements which are the interface between environment and electrical systems. The input of sensors is characteristics of the environment for example temperature, pressure and etc. and their output is a small electric voltage or current. Their job is to convert environment characteristics to an electric voltage or current at their outputs. Since the output current or voltage is very small, it must be amplified in order to be suitable for use in electronic systems. In this chapter we completely explain the design procedure and characteristics of sensor amplifiers. The important parameters of sensor amplifiers are input and output resistance, gain, unity gain bandwidth and etc. One of the most important characteristics of amplifiers is the linearity of amplification in a way that it must have uniformity for all amplitude voltages or currents in all frequencies of the bandwidth. For this purpose, first the operational amplifier is completely discussed, then the linearity of feedback operation will be explained.