ELCT 401:

ELECTRIC CIRCUITS II

INSTRUCTOR: PROF. YASSER HEGAZY

YASSER.HEGAZY@GUC.EDU.EG

Course Information and Introduction to

Operational Amplifiers

1

Course Outline

• Operational Amplifiers.

• Sinusoidal Steady State Analysis (AC Circuits)

• Power Calculations in AC circuits.

• Frequency Dependent Circuits

• Circuit Analysis in the Laplace Domain.

2

Study Plan Week Topic Laboratories Tutorials

Remarks

Week I Introduction

Week II Operational Amplifiers Start of all Labs Start of All tutorials

Week III Applications of OPAMPS

Week IV Circuit Elements in Phasor Domain

Week V AC Analysis

Week VI AC Power Calculations (I)

Midterm Exam ( no teaching )

Week VII AC Power Calculations (II) No lecture for

IET and MET

Week VIII Resonance

Week VIIII Filters No lecture for MCTR

Week X Circuit Analysis in “S” Domain No lectures for

IET and MET

Week XI Examples on “S” Domain No lecture for MCTR

Kindly note that lectures won’t be delivered in the following dates: Monday 20 March (midterm exams), Thursday 13 April (holy

Thurs.), Monday 20 April (Sham Elnasim)

3

Course Activities

• Lectures

• Monday 1st slot – H14 (IET)

• Monday 2nd slot – H14 (MET)

• Thursday 3rd slot – H13 (MCTR 1)

• Thursday 4th slot – H13 (MCTR 2)

• Tutorials.

One slot weekly, according to your schedule

• Laboratories.

One slot weekly, according to your schedule

4

Marking Scheme

• Assignments. 10 %

• Quizzes. 10 %

• Laboratories. 15 %

• Practical Project. 05 %

• Midterm Exam. 20 %

• Final Exam. 40 %

5

Resources

1.0 Text book

• Electric Circuits by, Nilsson & Riedel. 9th Edition

Chapters 5, 9 , 10 , 13, 14 and 15.

. Fundamental of Electric Circuits, by Alexander & Sadiku

Chapters 5, 9 , 10 , 11, 14 and 15.

2.0 Lab manual

• Posted on the course webpage.

3.0 Webpage:

• All course information will be available online at

http://eee.guc.edu.eg/

6

CHAPTER I

OPERATIONAL AMPLIFIERS

7

Objectives

• To introduce Operational Amplifiers as linear circuit elements.

• To identify the I-V characteristics of the operational amplifiers.

• To write KCL and KVL equations for the common amplifier

circuits.

• To solve circuits including one or more operational amplifiers.

• To calculate the gain of cascaded amplifiers’ circuits.

8

Op Amps

• Op Amp is short for operational amplifier.

• Amplifiers provide gains in voltage or current.

• Operational amplifiers or op amps are very useful electronic

components

• They are called “operational'' amplifiers, because they can be

used to perform arithmetic operations (addition, subtraction,

multiplication) with signals.

• In fact, op amps can also be used to integrate and differentiate

signals.

• The op amp is considered a 3-terminal linear circuit element.

9

Pin Assignment

10

Microscopic View of LS 741 OpAmp

11

Pin Assignment

• Pin # 2: Inverting input ( Vn)

• Pin # 3: Non-inverting input ( Vp)

• Pin # 6: The output( Vo )

• Pins # 4 & 7 : ±VCC(±5, ±10, ±13, ±15, ±20V)

• VCC are external voltage sources required to activate

the internal components of the operational amplifier

and to set the limits of the output voltage Vo such that:

-VCC ≤ Vo ≤VCC

12

Applications of Op Amps

• Op amps can be configured in many different ways

using resistors and other components.

• Most configurations use feedback.

• Op amps can provide a buffer between two circuits.

• Op amps can be used to implement integrators and

differentiators.

• Low-pass and band-pass filters.

13

The Op Amp Symbol

14

+

–

Non-inverting input

Inverting input

Ground

High Supply Vcc

Low Supply (-Vcc)

Output

Input – Output Characteristics

►Linear part

• Vo = A Vin

• A is the open loop gain.

• A has a fixed value

determined by the

manufacture.

• A ≥10,000

►Saturation

• Vo = ±Vcc

15

The Op Amp Model

• An operational amplifier is modeled as a voltage-controlled voltage

source.

16

+

– Inverting

input

Non-inverting

input Rin

vp

vn

+

–

A(v+ –

v– )

vo

Vo has a maximum value of Vcc, Vin≤ Vcc/A ≤ 2 mV

The input current in the order of nA