OneStopGate.Com
OnestopGate   OnestopGate
   Thursday, May 30, 2024 Login  
OnestopGate
Home | Overview | Syllabus | Tutorials | FAQs | Downloads | Recommended Websites | Advertise | Payments | Contact Us | Forum
OneStopGate

GATE Resources
Gate Articles
Gate Books
Gate Colleges 
Gate Downloads 
Gate Faqs
Gate Jobs
Gate News 
Gate Sample Papers
Training Institutes

GATE Overview
Overview
GATE Eligibility
Structure Of GATE
GATE Coaching Centers
Colleges Providing M.Tech/M.E.
GATE Score
GATE Results
PG with Scholarships
Article On GATE
Admission Process For M.Tech/ MCP-PhD
GATE Topper 2012-13
GATE Forum




GATE 2025 Exclusive
Organizing Institute
Important Dates
How to Apply
Discipline Codes
GATE 2025 Exam Structure

GATE 2025 Syllabus
Aerospace Engg..
Agricultural Engg..
Architecture and Planning
Chemical Engg..
Chemistry
Civil Engg..
Computer Science / IT
Electronics & Communication Engg..
Electrical Engg..
Engineering Sciences
Geology and Geophysics
Instrumentation Engineering
Life Sciences
Mathematics
Mechanical Engg..
Metallurgical Engg..
Mining Engg..
Physics
Production & Industrial Engg..
Pharmaceutical Sciences
Textile Engineering and Fibre Science

GATE Study Material
Aerospace Engg..
Agricultural Engg..
Chemical Engg..
Chemistry
Civil Engg..
Computer Science / IT
Electronics & Communication Engg..
Electrical Engg..
Engineering Sciences
Instrumentation Engg..
Life Sciences
Mathematics
Mechanical Engg..
Physics
Pharmaceutical Sciences
Textile Engineering  and Fibre Science

GATE Preparation
GATE Pattern
GATE Tips N Tricks
Compare Evaluation
Sample Papers 
Gate Downloads 
Experts View

CEED 2013
CEED Exams
Eligibility
Application Forms
Important Dates
Contact Address
Examination Centres
CEED Sample Papers

Discuss GATE
GATE Forum
Exam Cities
Contact Details
Bank Details

Miscellaneous
Advertisment
Contact Us


Home » Gate Study Material » Electrical Engineering » Electrical Elements » Operational Amplifiers

Operational Amplifiers

Looking for GATE Preparation Material? Join & Get here now!

** Gate 2013 Question Papers.. ** CEED 2013 Results.. ** Gate 2013 Question Papers With Solutions.. ** GATE 2013 CUT-OFFs.. ** GATE 2013 Results.. **

  Print
Operational Amplifiers

Why Are Operational Amplifiers Widely Used?

        This lesson is the first lesson on operational amplifiers, or op-amps as they are often called.

        Operational amplifiers are widely used in signal processing circuits, control circuits, and instrumentation.  Of all analog integrated circuits, the operational amplifier is the analog integrated circuit which has the most sales and is the most widely used in the widest variety of electronic circuits.  If you are an electrical engineer, you will probably encounter more operational amplifiers than any other integrated circuit device.  It's an important component for electrical engineers who design circuits using them and to all other kinds of engineers who use measurement and control circuits that contain operational amplifiers.



Where do you find Op-Amps?

        Operational amplifiers are used in many places including:

  • In strain gage circuitry to measure deformations in structures like bridges, airplane wings and I-beams in buildings.

  • In temperature measurement circuitry for boilers and in high altitude aircraft in a cold environment.

  • In control circuits for aircraft, people movers in airports, subways and in many different production operations.

        The operational amplifier is a versatile component that can do many things in measurement, signal processing and control.  That versatility is the largest reason that you find so many operational amplifiers being used!


Your Goals

        Your goal for this lesson should be:

  Given an operational amplifier you want to use,

  Be able to connect the positive and negative power supplies correctly.

  Be able to locate the inverting and non-inverting input terminals.


The 741 - A Typical Operational Amplifer

        This is a computer photograph of an operational amplifier.  It's often referred to as an operational amplifier.  We've called this module "The World of Op-Amps" because these creatures can be found almost everywhere you find electronic circuits.  Here is a typical operational amplifier on a circuit board.
 
 

        This particular operational amplifier is an integrated circuit.  Most operational amplifiers today are integrated circuits, even power operational amplifiers that can be used to drive small motors.  Of course the actual size is smaller than the picture above!

        Look carefully at the operational amplifier.  It's important to notice that there is a notch (sometimes a circular depression) on one end (the "top" of the chip in the picture) of the operational amplifier.  The pin shown below the notch is pin 1, and the one above is pin 8.  They're numbered counter clockwise around the chip.    Here is a drawing of the pinout

Above is a drawing of the pin-out.


What is an Op-Amp Really?

        An operational amplifier is a high gain, differential, voltage amplifier.

  • It is a voltage amplifier.  The input is a voltage and the output is a voltage.

  • The gain is high.  Typically, the gain is over 100,000

  • It is a differential amplifier.  It actually amplifies the difference between two voltages.


When Did Operational Amplifiers Arrive On The Scene?

        Operational amplifiers have been around since the late '40s or early '50s.  There have been a number of influential and interesting characters that worked with operational amplifiers including George Philbrick and Bob Widlar.


Using Operational Amplifiers

        If you want to use an operational amplifier, you will need to know several things.

  • You will need to know how to power up a chip.  In other words, you need to know how to get the power supply connected so that you can use the chip.  If you don't get the power supply connected the chip will not operate as an amplifier.

  • We'll spend a little time looking at those connections.

  • You will need to learn about circuits that use operational amplifiers.  That's the topic of the next lesson in this series.

        Examine the pinout for the chip.  Normally, the chip will either be inserted in a circuit board, or wired into a printed circuit board.  In either case, to power the chip you need to make two connections:

  • The positive voltage from the supply to pin 7 on the chip.

  • The negative voltage from the supply to pin 4 on the chip.

  • If you are used to using logic chips where the power goes to the corners, that's not quite what you have here.  It's different and be sure you get it right.

        Every operational amplifier will have some power supply connections.  Often they are not shown on the circuit digram for a circuit you are designing.  When necessary they are shown as below.  Here, Vcc is the positive supply voltage.  Usually,  Vcc  is 12 to 15 volts.  A negative supply is usually needed also, although there are operational amplifers on the martket that operate well just from a positive supply.  The negative supply,  -Vcc, is usually in the range from -12 to -15 volts.  When two supplies are used, they are the same voltage and of opposite sign in almost all cases.

        Often an integrated cirtcuit chip has a single operational amplifer.  The symbol for such an operational amplifier is shown below.  There are three voltages associated with this symbol.  Each voltage here is measured with respect to ground.

  • Vout  is the output voltage,

  • V+  is the non-inverting input voltage,

  • V-  is the inverting input voltage.

The chip diagram shows how an operational amplifier is connected internally in a typical 741 integrated circuit chip.  Notice that the voltages noted above are the actual connections you will need to make to use the amplifier.  They are not part of the power supply circuitry which is separate.

        Remember that the operational amplifier is a high gain, differential voltage amplifier.  In this case the output voltage is a very large multiple of the input voltage.  The multiplying factor is called the gain.  For a 741 operational amplifier, the gain is at least 100,000 and can be more than a million (1,000,000).  That's an important fact you'll need to remember as you put the 741 into a circuit.

        You don't need to know much more about wiring the operational amplifier or the internal connections to the amplifier.  There are some minor adjustment connections you could make, but you're probably OK for now.

        You still need to learn about operational amplifier circuits.  That's the next lesson, and you're ready to move on to it.  The lesson is the one on Inverting Amplifiers.   



Discussion Center

Discuss/
Query

Papers/
Syllabus

Feedback/
Suggestion

Yahoo
Groups

Sirfdosti
Groups

Contact
Us

MEMBERS LOGIN
  
Email ID:
Password:

  Forgot Password?
 New User? Register!

INTERVIEW EBOOK
Get 9,000+ Interview Questions & Answers in an eBook. Interview Question & Answer Guide
  • 9,000+ Interview Questions
  • All Questions Answered
  • 5 FREE Bonuses
  • Free Upgrades
GATE RESOURCES
 
  • Gate Books
  • Training Institutes
  • Gate FAQs
  • GATE BOOKS
     
  • Mechanical Engineeering Books
  • Robotics Automations Engineering Books
  • Civil Engineering Books
  • Chemical Engineering Books
  • Environmental Engineering Books
  • Electrical Engineering Books
  • Electronics Engineering Books
  • Information Technology Books
  • Software Engineering Books
  • GATE Preparation Books
  • Exciting Offers



    GATE Exam, Gate 2009, Gate Papers, Gate Preparation & Related Pages


    GATE Overview | GATE Eligibility | Structure Of GATE | GATE Training Institutes | Colleges Providing M.Tech/M.E. | GATE Score | GATE Results | PG with Scholarships | Article On GATE | GATE Forum | GATE 2009 Exclusive | GATE 2009 Syllabus | GATE Organizing Institute | Important Dates for GATE Exam | How to Apply for GATE | Discipline / Branch Codes | GATE Syllabus for Aerospace Engineering | GATE Syllabus for Agricultural Engineering | GATE Syllabus for Architecture and Planning | GATE Syllabus for Chemical Engineering | GATE Syllabus for Chemistry | GATE Syllabus for Civil Engineering | GATE Syllabus for Computer Science / IT | GATE Syllabus for Electronics and Communication Engineering | GATE Syllabus for Engineering Sciences | GATE Syllabus for Geology and Geophysics | GATE Syllabus for Instrumentation Engineering | GATE Syllabus for Life Sciences | GATE Syllabus for Mathematics | GATE Syllabus for Mechanical Engineering | GATE Syllabus for Metallurgical Engineering | GATE Syllabus for Mining Engineering | GATE Syllabus for Physics | GATE Syllabus for Production and Industrial Engineering | GATE Syllabus for Pharmaceutical Sciences | GATE Syllabus for Textile Engineering and Fibre Science | GATE Preparation | GATE Pattern | GATE Tips & Tricks | GATE Compare Evaluation | GATE Sample Papers | GATE Downloads | Experts View on GATE | CEED 2009 | CEED 2009 Exam | Eligibility for CEED Exam | Application forms of CEED Exam | Important Dates of CEED Exam | Contact Address for CEED Exam | CEED Examination Centres | CEED Sample Papers | Discuss GATE | GATE Forum of OneStopGATE.com | GATE Exam Cities | Contact Details for GATE | Bank Details for GATE | GATE Miscellaneous Info | GATE FAQs | Advertisement on GATE | Contact Us on OneStopGATE |
    Copyright © 2024. One Stop Gate.com. All rights reserved Testimonials |Link To Us |Sitemap |Privacy Policy | Terms and Conditions|About Us
    Our Portals : Academic Tutorials | Best eBooksworld | Beyond Stats | City Details | Interview Questions | India Job Forum | Excellent Mobiles | Free Bangalore | Give Me The Code | Gog Logo | Free Classifieds | Jobs Assist | Interview Questions | One Stop FAQs | One Stop GATE | One Stop GRE | One Stop IAS | One Stop MBA | One Stop SAP | One Stop Testing | Web Hosting | Quick Site Kit | Sirf Dosti | Source Codes World | Tasty Food | Tech Archive | Software Testing Interview Questions | Free Online Exams | The Galz | Top Masala | Vyom | Vyom eBooks | Vyom International | Vyom Links | Vyoms | Vyom World
    C Interview Questions | C++ Interview Questions | Send Free SMS | Placement Papers | SMS Jokes | Cool Forwards | Romantic Shayari