Operational Amplifiers: Example of an Integrated Circuit
5. Operational Amplifiers
Introduction In many electronic circuits, the signals (voltage differences) that are generated and manipulated are very small. Therefore, amplification is often essential. When playing a CD for instance, the signals generated in the CD player are quite small and will not adequately drive a speaker system. The signals from the CD player are therefore passed into the stereo amplifier (which often comes as a tuner/amplifier combination in modern home stereo systems). The heart of the stereo amplifier is the operational amplifier, or op-amp, which takes low level voltage signals as inputs and produces large output voltages that vary linearly with the input voltage.
Operational Amplifiers The op-amp is a simple example of an integrated circuit. The common 411 op-amp used in this laboratory contains 24 transistors on a single silicon chip. Many integrated circuits are much larger: a computer's microprocessor can contain several million separate elements. Each transistor is a three terminal semiconductor device that controls a large current with a small one. If you later study electronics, you will learn about transistors. In this course, we will omit that stage and show how the functioning of op-amp circuits can be understood without knowing anything about the individual transistors of which op-amps are composed. You need only understand a few basic principles (explained below) and Kirchoff's circuit laws. Our reason for doing this lab is to show you how practical problems can be solved using electronic devices. These days, most scientists solve practical instrumentation problems using op-amps and other integrated circuits rather than discrete components. An op-amp has three main terminals. The circuit symbol for an op-amp is shown in figure 1. The V- input is called the inverting input, the V+ input is called the non-inverting input, and Vout is the output voltage. All voltages are measured relative to the ground
Introduction In many electronic circuits, the signals (voltage differences) that are generated and manipulated are very small. Therefore, amplification is often essential. When playing a CD for instance, the signals generated in the CD player are quite small and will not adequately drive a speaker system. The signals from the CD player are therefore passed into the stereo amplifier (which often comes as a tuner/amplifier combination in modern home stereo systems). The heart of the stereo amplifier is the operational amplifier, or op-amp, which takes low level voltage signals as inputs and produces large output voltages that vary linearly with the input voltage.
Operational Amplifiers The op-amp is a simple example of an integrated circuit. The common 411 op-amp used in this laboratory contains 24 transistors on a single silicon chip. Many integrated circuits are much larger: a computer's microprocessor can contain several million separate elements. Each transistor is a three terminal semiconductor device that controls a large current with a small one. If you later study electronics, you will learn about transistors. In this course, we will omit that stage and show how the functioning of op-amp circuits can be understood without knowing anything about the individual transistors of which op-amps are composed. You need only understand a few basic principles (explained below) and Kirchoff's circuit laws. Our reason for doing this lab is to show you how practical problems can be solved using electronic devices. These days, most scientists solve practical instrumentation problems using op-amps and other integrated circuits rather than discrete components. An op-amp has three main terminals. The circuit symbol for an op-amp is shown in figure 1. The V- input is called the inverting input, the V+ input is called the non-inverting input, and Vout is the output voltage. All voltages are measured relative to the ground