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好久没看DesignIdea了.....
虽说没少仿真过分立元件搭建的运放,不过这个电路还是让我想仿真下,看看性能如何,结果.....
原文地址:http://www.edn.com/article/520186-Build_an_op_amp_with_three_discrete_transistors.php
Build an op amp with three discrete transistors
This simple ac-coupled design inverts, runs off a single supply, and is self-biasing.
Lyle Russell Williams, St Charles, MO; Edited by Paul Rako and Fran Granville -- EDN, December 1, 2011
You can use three discrete transistors to build an operational amplifier with an open-loop gain greater than 1 million (Figure 1). You bias the output at approximately one-half the supply voltage using the combined voltage drops across zener diode D1, the emitter-base voltage of input transistor Q1, and the 1V drop across 1-MΩ feedback resistor R2.
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Build an op amp with three discrete transistors figure 1Resistor R3 and capacitor C1 form a compensation network that prevents the circuit from oscillating. The values in the figure still provide a good square-wave response. The ratio of R2 to R1 determines the inverting gain, which is −10 in this example.
You can configure this op amp as an active filter or as an oscillator. It drives a load of 1 kΩ. The square-wave response is good at 10 kHz, and the output reduces by 3 dB at 50 kHz. Set the 50-Hz low-frequency response with the values of the input and the output capacitors. You can raise the high-frequency response by using faster transistors and doing careful layout.
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交流分析:
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以下为谐波失真分析的设置及曲线:
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阿莫论坛20周年了!感谢大家的支持与爱护!!
一只鸟敢站在脆弱的枝条上歇脚,它依仗的不是枝条不会断,而是自己有翅膀,会飞。
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