The document introduces a group of 5 students and provides information about LEDs (Light Emitting Diodes). It explains that LEDs are made from a combination of p-type and n-type semiconductors known as a pn junction. P-type semiconductors have extra holes that allow positive charge flow, while n-type have extra electrons that allow negative charge flow. LEDs only conduct current in the forward bias direction. Advantages of LEDs are that they are energy efficient, durable, and directional. Disadvantages include potential unreliability in varying outdoor temperatures and price control of rare earth materials used.

2. WE ARE:
1. Afnanul Hassan 161-15-7213
2. Khaled Akram Sany 161-15-7203
3. Shami Al Rahad 161-15-7349
4. Sohanur Rahman Sakib 161-15-7344
5. Nadeya Nusrat Ananna 161-15-6726

3. What Is LED (Light Emitting Diode)

5. P Type N Type

7. Any Semiconductor with impurity of
3 valance electrons, that makes a hole
(positive charge) in semiconductor is
called
p-type semiconductor.

9. Doping
+ =

11. Any Semiconductor with impurity of
5 valance electrons, that makes free
electron
(negative charge) in semiconductor is
called
n-type semiconductor.

13. Doping
+ =

16. Diode is usually made with pn
junction where pn junction
means the combination of p-type
& n-type semiconductor. That
conducts currents in forward bias
only.

21. Advantages:
Energy efficient source of light for short distances and small
areas. The typical LED requires only 30-60 mili watts to operate
Durable and shockproof unlike glass bulb lamp types
Directional nature is useful for some applications like reducing stray
light pollution on streetlights

22. Disadvantages:
May be unreliable in outside applications with great
variations in summer/winter temperatures.
Semiconductors are sensitive to being damaged by heat.
Rare earth metals used in LEDs are subject to price control
monopolies by certain nations.

23. ALLAH HaphejALLAH Haphej