Chapter 12 - Basic Analog Electronics: Operational Amplifiers

Abstract

This chapter provides an overview of analog operational amplifiers. Increasing the amplitude or gain of an analog signal is termed amplification and is achieved using an electronic device known as an amplifier. The properties of an amplifier are commonly introduced using a simplification called the ideal amplifier. An ideal amplifier is characterized by three features: (1) It has a well-defined gain at all frequencies (or at least over a specific range of frequencies); (2) Its output is an ideal source; and (3) Its input is an ideal load. An ideal amplifier has infinite input impedance, zero output impedance, and a fixed gain at all frequencies. An operational amplifier (op amp) has infinite input impedance and zero output impedance, but has infinite gain. The actual gain of an op amp circuit is determined by the feedback network, which is generally constructed from passive devices. This provides great flexibility with a wide variety of design options and the inherent robustness and long-term stability of passive elements. The concepts related to the operational amplifier, inverting amplifiers, and noninverting amplifier are elaborated. Limitations in transfer characteristics of real op amp are elaborated. It also discusses differential amplifier, adder, buffer amplifier, analog filters, and instrumentation amplifier.