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# Diodes

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Introduction to Diodes and their applications

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### Diodes

1. 1. Department of Electronics & Designed by Soujanya Roy, Anish Chakraborty and Raj Sekhar GoswamiCommunication Engineering
2. 2. 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. 3. Introduction- Basic Concepts Whats a diode? - Di+Ode - A semiconductor device with two terminals allowing the flow of current in one direction only.
4. 4. Introduction- Basic Concepts  What are diodes made out of?  Silicon  Germanium  GaAs
5. 5. Introduction- Basic Concepts  What are diodes made  Diamond lattice and Zinc Blende out of? Structure
6. 6. Introduction- Basic Concepts Diode Circuit Models Lets Browse through the three important diode circuit models
7. 7. Introduction- Basic Concepts Diode Circuit Models √ 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. 8. Introduction- Basic Concepts Diode Circuit Models √ The Ideal Diode with Barrier + V √ Potential 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. 9. Introduction- Basic Concepts Diode Circuit Models √ The Ideal Diode with Barrier Potential & Linear + V RF √ Forward Resistance 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. 10. Applications- Diodes & their uses Applications of Diodes in various Circuits √ √ √ √ √ √ √
11. 11. Getting into- Diodes & their uses Types of Diodes and their applications √ √ A K √ used to allow current to flow in one direction while Are Schematic Symbol for a PN Junction Diode blocking current flow in the opposite direction. P n Representative Structure for a PN Junction Diode
12. 12. Getting into- Diodes & their uses Types of Diodes and their applications √ √ A KAre specifically designed to operate under reverse breakdown Schematic Symbol for a Zener √conditions. These diodes have a very accurate and specific Diodereverse breakdown voltage.
13. 13. Getting into- Diodes & their uses Types of Diodes and their applications √ √ A KLight-emitting diodes are designed with a very large bandgapso movement of carriers across their depletion region emits Schematic Symbol for a Light- √ Emitting Diodephotons of light energy. Lower bandgap LEDs (Light-EmittingDiodes) emit infrared radiation, while LEDs with higher The arrows in the LEDbandgap energy emit visible light. representation indicate emitted light.
14. 14. Getting into- Diodes & their uses Types of Diodes and their applications √ While LEDs emit light, Photodiodes are √ sensitive to received light. They are A K constructed so their pn junction can be exposed to the outside through a clear √ window or lens. • Photoconductive Mode A K • Photovoltaic Mode Schematic Symbols for Photodiodes
15. 15. Getting into- Diodes & their uses Types of Diodes and their applications √ √ √
16. 16. Getting into- Diodes & their uses Types of Diodes and their applications √ √ √
17. 17. Getting Real- Video footage Letstake a look at the real diodes and their application in circuitry √ √ √
18. 18. Conclusion- Summing up Summing up all about diodes…!!! √ √ √ √ √
19. 19. Bibliography- References Thanks to the sources…!!! √ √ √ √ √
20. 20. THE END…√ √ √ √ √