1. Designed by Soujanya Roy, Anish Chakraborty and Raj Sekhar Goswami Department of Electronics & Communication Engineering

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. Introduction- Basic Concepts WWhats a diode? - Di+Ode - A semiconductor device with two terminals allowing the flow of current in one direction only.  C I R C U I T S Y M B O L

4. WWhat are diodes made out of?  Silicon  Germanium aAs }  D i a m o n d L a t t i c e S t r u c t u r e  Z i n c b l e n d e S t r u c t u r e

5. Introduction- Basic Concepts  What are diodes made out of?  Diamond lattice and Zinc Blende Structure

6. Introduction- Basic Concepts DDiode Circuit Models Lets Browse through the three important diode circuit models

7. 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. √ Introduction- Basic Concepts  Diode Circuit Models

8. Introduction- Basic Concepts  Diode Circuit Models The Ideal Diode with Barrier Potential √ √ VVV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. Introduction- Basic Concepts  Diode Circuit Models The Ideal Diode with Barrier Potential & Linear 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 R F (forward resistance) value is pretty constant. For low-power germanium and silicon diodes the R F value is usually in the 2 to 5 ohms range, while higher power diodes have a R F value closer to 1 ohm. + VVVV RFRFRFRF

10. Applications- Diodes & their uses  Applications of Diodes in various Circuits √ √ √ √ √ √ √

11. Getting into- Diodes & their uses TTypes of Diodes and their applications √ √ √ Are used to allow current to flow in one direction while blocking current flow in the opposite direction. AK Schematic Symbol for a PN Junction Diode Pn Representative Structure for a PN Junction Diode

12. Getting into- Diodes & their uses TTypes of Diodes and their applications √ √ √ Schematic Symbol for a Zener Diode AK Are specifically designed to operate under reverse breakdown conditions. These diodes have a very accurate and specific reverse breakdown voltage.

13. Getting into- Diodes & their uses TTypes of Diodes and their applications √ √ √ 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. AK Schematic Symbol for a Light- Emitting Diode The arrows in the LED representation indicate emitted light.

14. Getting into- Diodes & their uses TTypes of Diodes and their applications √ √ √ 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 Photoconductive Mode Photovoltaic Mode Photovoltaic Mode A A Schematic Symbols for Photodiodes K K

15. Getting into- Diodes & their uses TTypes of Diodes and their applications √ √ √

16. TTypes of Diodes and their applications √ √ √

17. Getting Real- Video footage LLets take a look at the real diodes and their application in circuitry √ √ √

18. Conclusion- Summing up  Summing up all about diodes…!!! √ √ √ √ √

19. Bibliography- References  Thanks to the sources…!!! √ √ √ √ √

20. THE END… √ √ √ √ √