Operational Amplifier

In 1947, after World War II, Professor John Ragazzini at the Columbia University of New York coined the operational amplifier concept. As a head of research, he pointed out that operation amplifiers can perform mathematical operations based on the applied input voltage. These mathematical operations include addition, subtraction, integration, and differentiation. In 1953, a commercial operational amplifier was available in the market and an IC-based operational amplifier was released in 1963 after the invention of IC. An operation amplifier, shortly op-amp is an analog electronic circuit block that takes a differential voltage input and produces a single-ended voltage output. In general, an op-amp is a voltage-amplifying device used with the circuit elements resistors and capacitors between the input and output. Operational amplifiers are classified as voltage amplifiers (voltage in and voltage out), current amplifiers (current in and current out), transconductance (voltage in and current out) and trans resistance (current in and voltage out). The basic op-amp is a three-terminal device with two inputs and one output. However, with two power supply terminals, it has five terminals: positive power supply, negative power supply, inverting input, noninverting input, and output as shown in Fig. 7.1. This chapter will discuss different types of operational amplifiers and their mathematical analysis.