Instrumentaçãp

CALIFORNIA INSTITUTE OF TECHNOLOGY PHYSICS MATHEMATICS AND ASTRONOMY DIVISION

Sophomore Physics Laboratory (PH005/105)

Analog Electronics: Basic OpAmp Applications:
Academic Year 2009-2010 Copyright©Virgínio de Oliveira Sannibale, 2001

Contents
5 Basic Op-Amp Applications 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1.1 Inverting Summing Stage . . . . . . . . . . . . . . . . 5.1.2 Basic Instrumentation Amplifier . . . . . . . . . . . . 5.1.3 Voltage to Current Converter (Transconductance Amplifier) . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1.4 Current to Voltage Converter (Transresistance Amplifier) . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 Logarithmic Circuits . . . . . . . . . . . . . . . . . . . . . . . 5.2.1 Logarithmic Amplifier . . . . . . . . . . . . . . . . . . 5.2.2 Anti-Logarithmic Amplifier . . . . . . . . . . . . . . . 5.2.3 Analog Multiplier . . . . . . . . . . . . . . . . . . . . 5.2.4 Analog Divider . . . . . . . . . . . . . . . . . . . . . . 5.3 Multiple-Feedback Band-Pass Filter . . . . . . . . . . . . . . 5.4 Peak and Peak-to-Peak Detectors . . . . . . . . . . . . . . . . 5.5 Zero Crossing Detector . . . . . . . . . . . . . . . . . . . . . . 5.6 Analog Comparator . . . . . . . . . . . . . . . . . . . . . . . . 5.7 Regenerative Comparator (The Schmitt Trigger) . . . . . . . 5.8 Phase Shifter . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.9 Problems Preparatory to the Laboratory . . . . . . . . . . . . 5.10 Laboratory Procedure . . . . . . . . . . . . . . . . . . . . . . . 3 3 3 4 5 6 7 8 8 9 10 10 11 12 12 13 15 16 16

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Chapter 5 Basic Op-Amp Applications
5.1 Introduction
In this chapter we will briefly describe some quite useful circuit based on Op-Amp, bipolar junction transistors, and diodes.

5.1.1 Inverting Summing Stage
R V1 I1 R V2 I2 R Vn In I
−

Rf I A
+

Vo

Figure 5.1: Inverting summing stage using an Op-Amp. The analysis of the circuit is