The amplifier's differential inputs consist of a non-inverting input (+) with voltage V+ and an inverting input (−) with voltage V−; ideally the op amp amplifies only the difference in voltage between the two, which is called the

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Ideal op amps
An ideal op amp is usually considered to have the following characteristics:
• Infinite

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Sourced by many manufacturers, and in multiple similar products, an example of a bipolar transistor operational amplifier is the 741 integrated circuit designed in 1968 by David Fullagar at

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Op amps may be classified by their construction:
• discrete, built from individual transistors or tubes/valves
• integrated circuit, most common
• hybrid

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1941: A vacuum tube op amp. An op amp, defined as a general-purpose, DC-coupled, high gain, inverting feedback amplifier, is first found in U.S. Patent 2,401,779"Summing Amplifier" filed

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• Active filter
• Analog computer
• Bob Widlar
• Current conveyor

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Use in electronics system design
The use of op amps as circuit blocks is much easier and clearer than specifying all their individual circuit elements (transistors, resistors,

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