6.2.6 Differential Amplifiers

Chapter 6.2.6 Differential Amplifiers

Physics Lecture Notes – Phys 395 Electronics Book
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Physics Lecture Notes – Phys 395 Electronics Book

  • CHAPTER 6. OPERATIONAL AMPLIFIERS115 V1(t)V3=----- V2(t)V2(t)V1(t)MULTFigure 6.16: A multiplier as part of the feedback loop that results in the division operation.v2(t)=sqrt(v1(t))V1(t)MULTFigure 6.17: A multiplier as part of the feedback loop that results in the square-root opera-tion.6.2.6Differential AmplifiersThe differential amplifier amplifies the difference between two input signals (−) and (+).This amplifier is also referred to as a differential-input single-ended output amplifier. It isa precision voltage difference amplifier, and forms the central basis of more sophisticatedinstrumentation amplifier circuits.A differential amplifier is shown in figure 6.18. The voltage V3 is given by (cf. voltagedivider)V3V3R2R1R2R1VoutV2V1Figure 6.18: Differential amplifier.V3 =R2R1 + R2V2,(6.28)