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DIODES AND THEIR APPLICATIONS

DIODES AND THEIR APPLICATIONS. Designed by Soujanya Roy, Anish Chakraborty and Raj Sekhar Goswami. Department of Electronics & Communication Engineering. DIODES AND THEIR APPLICATIONS. AGENDA. Introduction to the Basic concepts of Diodes - Whats a diode?

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DIODES AND THEIR APPLICATIONS

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  1. DIODES AND THEIR APPLICATIONS Designed by Soujanya Roy, AnishChakraborty and Raj SekharGoswami Department of Electronics & Communication Engineering

  2. DIODES AND THEIR APPLICATIONS AGENDA • Introduction to the Basic concepts of Diodes - Whats a diode? - What are diodes made out of? - Diode Circuit Models • Applications of diodes in various circuits • Getting into: - Types of diodes - Their uses • Getting Real - Lets take a look at the real diodes - Video footage • Conclusion • Bibliography

  3. DIODES AND THEIR APPLICATIONS Introduction- Basic Concepts • Whats a diode? - Di+Ode - A semiconductor device with two terminals allowing the flow of current in one direction only.  CIRCUIT SYMBOL

  4. DIODES AND THEIR APPLICATIONS Introduction- Basic Concepts • What are diodes made out of? • Silicon • Germanium • GaAs }  Diamond Lattice Structure  Zincblende Structure

  5. DIODES AND THEIR APPLICATIONS Introduction- Basic Concepts • What are diodes made out of? • In both the diamond lattice and zincblend lattice, each atom shares its valence electrons with its four closest neighbors. This sharing of electrons is what ultimately allows diodes to be build. When dopants from groups 3 or 5 (in most cases) are added to Si, Ge or GaAs it changes the properties of the material so we are able to make the P- and N-type materials that become the diode. • Diamond lattice and Zinc Blende • Structure

  6. DIODES AND THEIR APPLICATIONS Introduction- Basic Concepts • Diode Circuit Models • Ideal Diode Model • The Ideal Diode with Barrier Potential • The Ideal Diode with Barrier Potential and Linear Forward Resistance Lets Browse through the three important diode circuit models

  7. DIODES AND THEIR APPLICATIONS Introduction- Basic Concepts • Diode Circuit Models • Ideal Diode Model • The Ideal Diode with Barrier Potential • The Ideal Diode with Barrier Potential and Linear Forward Resistance The Ideal Diode Model √ The diode is designed to allow current to flow in only one direction. The perfect diode would be a perfect conductor in one direction (forward bias) and a perfect insulator in the other direction (reverse bias). In many situations, using the ideal diode approximation is acceptable.

  8. DIODES AND THEIR APPLICATIONS Introduction- Basic Concepts • Diode Circuit Models • Ideal Diode Model • The Ideal Diode with Barrier Potential • The Ideal Diode with Barrier Potential and Linear Forward Resistance The Ideal Diode with Barrier Potential √ + V √ This model is more accurate than the simple ideal diode model because it includes the approximate barrier potential voltage. Remember the barrier potential voltage is the voltage at which appreciable current starts to flow.

  9. DIODES AND THEIR APPLICATIONS Introduction- Basic Concepts • Diode Circuit Models The Ideal Diode with Barrier Potential & Linear Forward Resistance • Ideal Diode Model • The Ideal Diode with Barrier Potential • The Ideal Diode with Barrier Potential and Linear Forward Resistance √ + V RF √ This model is the most accurate of the three. It includes a linear forward resistance that is calculated from the slope of the linear portion of the transconductance curve. However, this is usually not necessary since the RF (forward resistance) value is pretty constant. For low-power germanium and silicon diodes the RF value is usually in the 2 to 5 ohms range, while higher power diodes have a RF value closer to 1 ohm. √

  10. DIODES AND THEIR APPLICATIONS Applications- Diodes & their uses • Applications of Diodes in various Circuits √ • Reverse voltage Protection • Rectifying • Display • Light Sensing √ √ √ √ √ √

  11. DIODES AND THEIR APPLICATIONS Getting into- Diodes & their uses • Types of Diodes and their applications √ • THE BASIC SEMICONDUCTOR DIODE PN Junction Diodes: A K √ Are used to allow current to flow in one direction while blocking current flow in the opposite direction. Schematic Symbol for a PN Junction Diode √ P n Representative Structure for a PN Junction Diode

  12. DIODES AND THEIR APPLICATIONS Getting into- Diodes & their uses • Types of Diodes and their applications √ • THE ZENER DIODE √ A K Are specifically designed to operate under reverse breakdown conditions. These diodes have a very accurate and specific reverse breakdown voltage. Schematic Symbol for a Zener Diode √

  13. DIODES AND THEIR APPLICATIONS Getting into- Diodes & their uses • Types of Diodes and their applications √ • THE LIGHT EMITTING DIODES (LEDS) A K √ Light-emitting diodes are designed with a very large bandgap so movement of carriers across their depletion region emits photons of light energy. Lower bandgap LEDs (Light-Emitting Diodes) emit infrared radiation, while LEDs with higher bandgap energy emit visible light. Schematic Symbol for a Light-Emitting Diode √ The arrows in the LED representation indicate emitted light.

  14. DIODES AND THEIR APPLICATIONS Getting into- Diodes & their uses • Types of Diodes and their applications √ • THE PHOTO DIODES • While LEDs emit light, Photodiodes are sensitive to received light. They are constructed so their pn junction can be exposed to the outside through a clear window or lens. • Photoconductive Mode • Photovoltaic Mode A K √ √  A K Schematic Symbols for Photodiodes

  15. DIODES AND THEIR APPLICATIONS Getting into- Diodes & their uses • Types of Diodes and their applications √ • DIODE AS A RECTIFIER: • HALF WAVE RECTIFIER √ √

  16. DIODES AND THEIR APPLICATIONS Getting into- Diodes & their uses • Types of Diodes and their applications √ • DIODE AS A RECTIFIER: • FULL WAVE RECTIFIER √ √

  17. DIODES AND THEIR APPLICATIONS Getting Real- Video footage • Lets take a look at the real diodes and their application in circuitry √ • VIDEO FOOTAGE √ √

  18. DIODES AND THEIR APPLICATIONS Conclusion- Summing up • Summing up all about diodes…!!! √ • Unidirectional device permitting easy flow of current in one direction. • Semiconductor diode basically a pn junction diode. • Diode circuit models, Ideal diode: two terminal polarity sensitive device. Forward bias: Zero Resistance; Reverse bias : infinite resistance. • Brief Insight of various diodes and their uses and applications in different circuits. √ √ √ √

  19. DIODES AND THEIR APPLICATIONS Bibliography- References • Thanks to the sources…!!! √ • Electronic Devices and Circuits – JB GUPTA • http://en.wikipedia.org • www.google.com • Analog Electronics Tutorial Series DIODES, Kristin Ackerson, Virginia Tech EE, Spring 2002 √ √ √ √

  20. DIODES AND THEIR APPLICATIONS THE END… THANK YOU AND HAVE A NICEDAY…!!! - Soujanyaroy, anishchakraborty and raj sekhargoswami √ √ √ √ √

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