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二、加减运算电路 |
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(一)加法电路 |
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I1=(U11-UA)/R1=U11/R1 |
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I1=U12/R2
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Uo=-IfRf=-(I1+I2+I3)Rf=-(U11Rf/R1+U12Rf/R2+U13Rf/R3) |
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输出电压等于各输入电压按照不同比例相加之和。 |
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(二)减法电路 |
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Uo=-U12{R4/(R3+R4)}{(R1+R2)/R1}-U11R2/R1 |
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R1=
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Uo=-(U11-U12)R2/R1 |
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输出电压与两个输入电压的差值UId=UI1-UI2成正比，电路实现了差值运算。差值运算放大器也称为差动运算放大器。 |
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