5.1 Introduction

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5.1 Introduction

Having learned the basic la ws and theorems for circuit analysis, we are now ready to study an acti ve circuit element of paramount importance: the operational amplifier, or op amp for short. The op amp is a versatile circuit building block.

The op amp is an electronic unit that behaves like a voltage-controlled voltage source.

It can also be used in making a v oltage- or current -controlled current source. An op amp can sum signals, amplify a signal, inte grate it, or differentiate it. The ability of the op amp to perform these mathematical operations is the reason it is called an operational amplifier. It is also the reason for the widespread use of op amps in analog design. Op amps are popular in practical circuit designs because the y are versatile, inexpensive, easy to use, and fun to work with.

We begin by discussing the ideal op amp and later consider the nonideal op amp. Using nodal analysis as a tool, we consider ideal op amp circuits such as the in verter, voltage follower, summer, and dif ference amplifier. We will also analyze op amp circuits with PSpice. Finally, we learn how an op amp is used in digital-to-analog converters and instrumentation amplifiers.