OnestopGate   OnestopGate
   Tuesday, May 30, 2023 Login  
Home | Overview | Syllabus | Tutorials | FAQs | Downloads | Recommended Websites | Advertise | Payments | Contact Us | Forum

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

GATE 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 2024 Exclusive
Organizing Institute
Important Dates
How to Apply
Discipline Codes
GATE 2024 Exam Structure

GATE 2024 Syllabus
Aerospace Engg..
Agricultural Engg..
Architecture and Planning
Chemical Engg..
Civil Engg..
Computer Science / IT
Electronics & Communication Engg..
Electrical Engg..
Engineering Sciences
Geology and Geophysics
Instrumentation Engineering
Life Sciences
Mechanical Engg..
Metallurgical Engg..
Mining Engg..
Production & Industrial Engg..
Pharmaceutical Sciences
Textile Engineering and Fibre Science

GATE Study Material
Aerospace Engg..
Agricultural Engg..
Chemical Engg..
Civil Engg..
Computer Science / IT
Electronics & Communication Engg..
Electrical Engg..
Engineering Sciences
Instrumentation Engg..
Life Sciences
Mechanical Engg..
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
Application Forms
Important Dates
Contact Address
Examination Centres
CEED Sample Papers

Discuss GATE
GATE Forum
Exam Cities
Contact Details
Bank Details

Contact Us

Home » GATE Study Material » Electrical Engineering » Electrical Elements » Using Diodes To Rectify Signals

Using Diodes To Rectify Signals

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.. **

Using Diodes To Rectify Signals

What is "Signal Rectification"?

        Signal rectification is a process in which you process an AC (Alternating Current) signal (often sinusoidal) to get a DC signal or a signal with a DC component.

Why Rectify Signals

        There are many situations in which you want to "rectify" a signal.  Here are some of the most common situations.

  • In power supplies the AC supply voltage (60 Hz in the U.S., from the wall plug) is converted to a constant DC value to power electronic circuits that require a constant voltage to operate.  Examples include the following:

    • Computers

    • Television sets

    • Radios

    • Stereo Systems

    • Guitar Amplifiers & Sound Systems in General

  • In signal systems, information coded into the amplitude of a sinusoidal signal must be rectified to extract the information.  Examples include the following:

    • AM radios

    • Sensors - like some kinds of tachometers - which produce a sinusoidal signal where the amplitude encodes the value of a physical quantity like rotational rate.

Signal rectification is an important concept and is often used in a variety of systems.

Simple Signal Rectification

        Here is a simple signal rectifier.  When the input voltage is positive, the output voltage is approximately equal to the input.

Using A Capacitor In A Rectifier - Building A Peak Detector

        Here is a circuit.

Here is what happens in this circuit.

  • When the sinusoidal input is increasing and the capacitor is uncharged, current flows through the diode to charge the capacitor.  (Remember, current is just charge flowing, so when current flows through the diode into the capacitor, charge accumulates in the capacitor.)

  • At some point in time, the input voltage begins to decrease.  At that point, the diode stops conducting and the capacitor/resistor combination is effectively cut off from the rest of the circuit and the capacitor begins to discharge through the resistor.

  • As the capacitor discharges, eventually the input voltage gets to a point where it equals the capacitor voltage, and the diode begins conducting again, charging the capacitor in the process.

       There are some things to consider.  The first point to consider is just how far the voltage will droop from the peak until it begins to increase again.  Just past the peak the voltage across the capacitor will decrease for a short while.  What happens is that the input voltage (the sine wave) is decreasing but not decreasing very quickly.  (As you get further from the peak the voltage begins to decrease more quickly.)  When the input voltage is not decreasing very quickly, the charge flowing out of the capacitor can flow through the resistor, and there will still be current flowing through the diode.  (Some of the current flowing through the diode comes from charge on the capacitor, and some flows through the diode.)  However, sooner or later, the input voltage gets to the point where it is decreasing faster than the capacitor voltage can change.  The limit on how fast the capacitor can discharge is determined by the resistor.  For a given voltage, Vout on the capacitor, the current out of the capacitor is limited to Vout/R.  Since the capacitor current is CVoutd/dt, the rate of change of capacitor voltage can be computed as dVout/dt = -Vout/(RC).  At that point

        There are a few other points to note about this circuit.

  • The resistor in parallel with the capacitor may well be the internal resistance of the capacitor.

  • The simulation above assumes that the diode is an ideal diode.  That's pictured below with the bold red graph.

 We can add a "bias" to the diode model to get closer to reality.  The voltage-current curve for a better model is shown below.  Click the button to see how closely the model comes to the v-i curve for a "typical" diode.

If we incorporate that model into our simulation, then the simulation is different.

You can see in the simulation that the output voltage does not quite follow the input voltage - due to the threshold voltage in the diode.

Discussion Center







Email ID:

  Forgot Password?
 New User? Register!

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 Books
  • Training Institutes
  • Gate FAQs
  • 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 | GATE Exam Cities | Contact Details for GATE | Bank Details for GATE | GATE Miscellaneous Info | GATE FAQs | Advertisement on GATE | Contact Us on OneStopGATE |
    Copyright © 2023. One Stop 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