Characteristics of Op-amp: Introduction

Introduction

The operational amplifier, most commonly referred as 'op-amp' was introduced in 1940s. The first operational amplifier was designed in 1948 using vacuum tubes. In those days, it was used in the analog computers to perform a variety of mathematical operations such as addition, subtraction, multiplication etc. Due to its use in performing mathematical operations it has been given a name operational amplifier. Due to the use of vacuum tubes, the early op-amps were bulky, power consuming and expensive.

Robert J. Widlar at Fairchild brought out the popular 741 Integrated Circuit (IC) op-amp between 1964 to 1968. The IC version of op-amp uses BJTs and FETs which are fabricated along with the other supporting components, on a single semiconductor chip or wafer which is of a pinhead size. With the help of IC op-amp, the circuit design becomes very simple. The variety of useful circuits can be built without the necessity of knowing about the complex internal circuitry. Moreover, IC op-amps are inexpensive, take up less space and consume less power. The IC op-amp has become an integral part of almost every electronic circuit which uses linear integrated circuit. The modern linear IC op-amp works at lower voltages. It is so low in cost that millions are now in use, annually.

Ket Point : Because of their low cost, small size, versatility, flexibility and dependability, op-amps are used in the fields of process control, communications, computers, power and signal sources, displays and measuring systems.

The op-amp is basically an excellent high gain d.c. amplifier.