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Operational Amplifiers

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Operational Amplifiers

He who will not reason is a bigot; he who cannot is a fool; and he who dares not is a slave.

—Lord Byron

Enhancing Your Career

Career in Electronic Instrumentation

Engineering involves applying physical principles to design devices for the benefit of humanity. But ph ysical principles cannot be understood without measurement. In f act, ph ysicists often say that ph ysics is the science that measures reality. Just as measurements are a tool for understanding the physical world, instruments are tools for measurement. The operational amplifier introduced in this chapter is a building block of modern electronic instrumentation. Therefore, mastery of operational amplifier fundamentals is paramount to any practical application of electronic circuits.

Electronic instruments are used in all fields of science and engineering. They have proliferated in science and technology to the e xtent that it would be ridiculous to have a scientific or technical education without exposure to electronic instruments. For example, physicists, physiologists, chemists, and biologists must learn to use electronic instruments. For electrical engineering students in particular, the skill in operating digital and analog electronic instruments is crucial. Such instruments include ammeters, v oltmeters, ohmmeters, oscilloscopes, spectrum analyzers, and signal generators.

Beyond de veloping the skill for operating the instruments, some electrical engineers specialize in designing and constructing electronic instruments. These engineers deri ve pleasure in b uilding their o wn instruments. Most of them invent and patent their inventions. Specialists in electronic instruments find employment in medical schools, hospitals, research laboratories, aircraft industries, and thousands of other indus tries where electronic instruments are routinely used.

Electronic Instrumentation used in medical research. © Royalty-Free/Corbis

Learning Objectives

By using the information and exercises in this chapter you will be able to:

    1. Comprehend how real operational amplifiers (op amps) function.
    1. Understand that ideal op amps function nearly identically to real ones and that they can be used to model them effectively in a variety of circuit applications.
    1. Realize how the basic inverting op amp is the workhorse of the op amp family.
    1. Use the inverting op amp to create summers.
    1. Use the op amp to create a difference amplifier.
    1. Explain how to cascade a variety of op amp circuits.