Linear Integrated Circuits - Basics of Op-Amp

LINEAR INTEGRAted circuits

MODULE 1

Introduction of Linear ICs

START

ÍNDEX

INDEX

01

03

02

Objectives

Basic Information of Op-Amp

The Ideal Operational Amplifier

05

04

Voltage Follower

Inverting and Non-inverting Amplifier

OBJECTIVES

OBJECTIVES

At the end of this course, you will be able to

Describe the characteristics and internal circuit of Op-Amp

Differentiate between the Ideal and Actual Operational Amplifier

Demonstrate the usage of Inverting and Non-inverting amplifier

Explain the function of Voltage follower and solve problems related to the circuit

BASICS OF OP-AMP

BASICS OF OP-AMP

QUIZ

QUIZ

Which of these, is the most commonly used Op-Amp

IC741

IC891

IC471

QUIZ

QUIZ

RIGHT ANSWER!

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QUIZ

QUIZ

Which terminal points to the inverting input in the op-amp?

IC-741

Click on the right terminal

QUIZ

QUIZ

RIGHT ANSWER!

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QUIZ

QUIZ

From which terminal will you extract the output signal from the op-amp?

IC-741

Click on the right terminal

QUIZ

QUIZ

RIGHT ANSWER!

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BASICS OF OP-AMP

THE IDEAL OPERATIONAL AMPLIFIER

Click on each tab to view the properties

ACTUAL Op-amp

Ideal Op-amp

QUIZ

QUIZ

Which of the following characteristics are true for an ideal op-amp

Aol=1Ri=0 Ro=∞

Aol=∞ Ri=∞ Ro=0

Aol=0Ri=∞ Ro=0

QUIZ

QUIZ

RIGHT ANSWER!

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BASICS OF OP-AMP

OPEN LOOP OPERATION OF OP-AMP

• Simplest way to use an op-amp

• Gain Aol = ∞; Vo -> positive saturation voltage (+Vsat) if V1>V2 or negative saturation voltage (-Vsat) if V1<V2.

• Only two possible states + Vsat or - Vsat

• Acts as a switch

QUIZ

QUIZ

What is the general use of the open-loop circuit of the op-amp

Integrator

Switch

Differentiator

QUIZ

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RIGHTANSWER!

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Basics of op-amp

FEEDBACK IN AN IDEAL OP-AMP

• Connecting the output of the op-amp to its inverting input.

NEGATIVE FEEDBACK

• An op-amp with negative feedback will try to drive its output voltage to whatever level necessary so that the differential voltage between the two inputs is practically zero. The higher the op-amp differential gain, the closer that differential voltage will be to zero. The circuit will quickly reach a point of stability or equillibrium.

QUIZ

QUIZ

How can we provide negative feedback to the Op-amp?

Connect the output of the op-amp to the ground

Connect the output of the op-amp to the non-inverting input

Connect the output of the op-amp to its inverting input

QUIZ

QUIZ

RIGHTANSWER!

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BASICS of OP-AMP

THE INVERTING AMPLIFIER

Ideal Op-Amp Characteristics

Vd = 0; I1 = Vi R1

Vo = -I1. Rf = -Vi. RfR1

Closed Loop Gain,Acl= Vo = -Rf = - Zf Vi R1 Zi

Acl= Vo = -Zf Vi Z1

BASICS of OP-AMP

THE Practical INVERTING AMPLIFIER

Closed Loop Gain, Acl= Vo = -Rf Vi R1Input Resistance, Rif= Rf+Ro 1+Aol Output Resistance, Rof= Ro (R1+Rf) Ro +R1+Rf 1+ R1Aol Ro+R1+Rf

BASICS of OP-AMP

THE NON-INVERTING AMPLIFIER

Vd = 0; Vi = Vo. R1 R1 + Rf

Closed Loop Gain,Acl= Vo = R1+Rf = 1 + Rf Vi R1 R1

QUIZ

QUIZ

Which of these equations represent the gain of an inverting amplifier?

Aol=1+ Rf Ri

Aol=-Ri Rf

Aol=-Rf Ri

QUIZ

QUIZ

RIGHTANSWER!

RESULTS

QUIZ

QUIZ

Which of the following statements is true for an non-inverting amplifier?

The output signal should not be fedback to the input terminals

The input signal should be applied to the inverting input of op-amp

The output signal is amplified without inverting of the input signal

QUIZ

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RIGHTANSWER!

RESULTS

BASICS OF OP-AMP

VOLTAGE FOLLOWER

• Rf=0 and R1=∞ =>Voltage Follower

• Vo=Vi both in magnitude and phase

• UNITY gain

• Used as buffer for impedance macthing to connect a high impedance source to a low impedance load

QUIZ

QUIZ

Where is the voltage follower commonly used?

Switch

Integrator

Buffer for impedance matching

QUIZ

QUIZ

RIGHTANSWER!

RESULTS

BASIC OF OP-AMP

LEARNING EXPERIENCE

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THANK YOU!