1

WELCOME!

MUHSIN BAKHTIAR MAFAZ (1409054)

FARHAN MAHMUD HEMEL (1409051)

2

LED & P in D iode

LED

4

A light emitting diode (LED) is essentially a PN junction opto-semiconductor that emits a monochromatic (single color) light when operated in a forward biased direction.

W h a t i s L E D ? ?

5

H o w d o e s L E D

w o r k s ? ?

Sufficient voltage is applied to the chip across the leads.

Electrons moves easily in one direction across the junction between the p and n regions.

P region contains many more positive than negative charges.

Voltage is applied and the current starts to flow.

Electrons in the n region contains sufficient energy to move across the junction into the p region.

4

3

5

2

1

6

H o w d o e s L E D

w o r k s ? ?

Electron recombines with a positive charge.

Electric potential energy is converted into electromagnetic energy.

For each recombination of a negative and a positive charge, a quantum of electromagnetic energy is emitted in the form of a photon.

6

7

8

8

8

K I N D S O F L E D

7

Starburst

7-Segment Dot Matrix

Baragraph

8

A p p l i c a t i o n o f L E D

1

2

3 Sign Applications

4

5LED Signals

6I l luminations

Sensor Applications

Mobile Applications

Automative Uses

9

Benefits

Long Lifetime

Design Flexibili

ty

Directional

Energy Efficienc

yPower supply

EcoFriendly

LED’s can be controlled for brightness and color.

With LED’s you can direct the light where you want it, thus no light is wasted.

A low-voltage power supply is sufficient for LED illumination.

LEDs have a lifespan of up to 60,000 hours compared to 1,500 hours for incandescent bulbs. An LED light will last over 7 years.

LEDs are extremely energy efficient and consume up to 90% less power than incandescent bulbs

LED lights contain no toxic materials and are 100% recyclable.

ADVANTAGES

P IN D iode

11

A PIN diode is a diode with a wide, lightly doped 'near' intrinsic semiconductor, region between a p-type semiconductor and an n-type semiconductor region.

The p-type and n-type regions are typically heavily doped because they are used for ohmic contacts.

D E F I N I T I O N

12

Point 1The speed of the PIN diode is limited by variation in the time it takes electrons to pass through the device. This time spread can be spread in two ways:

By increasing the bias-voltage By reducing the thickness of

intrinsic layer

Point 2The PIN diode an inferior rectifier but it makes the PIN diode suitable for attenuators, fast switches, photodetectors, and high voltage power electronics applications.

Point 3 TYPES: Metal-Semiconductor PIN

diode Heterojunction PIN diode

I N T R O D U C T I O NThe wide intrinsic region is in contrast to an ordinary PN diode.In it :

CONSTRUCT ION

14

When the forward bias control current of the PIN diode is varied continuously, it can be used for attenuating, leveling, and amplitude modulating an RF signal.

OPERATIONSThe basic operation of a pin diode includes:

When the control current is switched on and off, or in discrete steps, the device can be used for switching, pulse modulating, and phase shifting an RF signal.

When the diode is forward biased, holes and electrons are injected into the I-region. This charge does not recombine instantaneously, but has a finite lifetime (t) in the I-region.

If the PIN diode is reverse biased , there is no stored charge in the I-region and the device behaves like a Capacitance (CT) shunted by a parallel resistance (RP).

15

C O N C E P T

A drawing of a PIN diode chip is shown in Figure 1.1 (a). The performance characterist ics of the PIN diode depend mainly on the chip geometry and the processed semiconductor material in

the intr insic or I - region, of the finished diode.

16

A P P L I C A T I O N S

It is used as a Photo Detector for most fiber optic application. The greater depletion improves the conversion of light to current.

Photo Detector

As the intrinsic region provides a greater separation between the P & N regions, allowing higher reverse voltage to be tolerated.

High Voltage Rectifier

They are used in electronic pre-amplifier to boost sensitivity.

Electronic Pre-amplifier

Widely used in RF modulator circuit to control RF intermodulation distortion. At high frequencies, the pin diode acts as a resistor.(in attenuetor designs).

RF Modulation

This diode In a phase shifter circuit is considered as a lumped variable-impedance microwave circuit element.

In Phase Shifting Ckt

The PIN diode makes an ideal RF Switch. The intrinsic layer between the P & N regions increases the distance between them, thereby increasing the level of isolation in reverse bias condition.

RF Switch

ABOUT US!Dept. of Electronics & Communication EngineeringKhulna University of Engineering & Technology

01953889101

01940278741

THANK YOU!