Optoelectronics combines electronics and optics to study and apply electronic devices that interact with light. Major optoelectronic devices include light-emitting diodes (LEDs), laser diodes, photodiodes, and solar cells. A light emitting diode (LED) is an optical diode that emits light when forward biased. LEDs use semiconductors like gallium arsenide to emit light of different colors depending on the material's band gap. They have advantages like small size, long life, and availability in many colors.
Basic of semiconductors and optical propertiesKamran Ansari
This presentation explains the band structure, intrinsic semiconductor, extrinsic semiconductor, electrical conductivity, mobility, hall effect, p-n junction diode, tunnel diode and optical properties of the semiconductor.
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The term "laser" originated as an acronym for "light amplification by stimulated emission of radiation
Introduction to semiconductor lasers, and its working. construction of semiconductor laser, Ga As laser, and construction, achievement of population inversion, pumping.
Basic of semiconductors and optical propertiesKamran Ansari
This presentation explains the band structure, intrinsic semiconductor, extrinsic semiconductor, electrical conductivity, mobility, hall effect, p-n junction diode, tunnel diode and optical properties of the semiconductor.
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The term "laser" originated as an acronym for "light amplification by stimulated emission of radiation
Introduction to semiconductor lasers, and its working. construction of semiconductor laser, Ga As laser, and construction, achievement of population inversion, pumping.
This ppt will explain the basic operation, advantages, disadvantages, applications of LED and operation, characteristics and applications of varactor diodes.
LEDs are of interest for fibre optics because of five inherent characteristics..
How it works?
Spectrum of an LED
Modulation of LED
LED Vs. Laser diode
disadvantages of LED
A ruby laser is a solid-state laser that uses the synthetic ruby crystal as its laser medium. Ruby laser is the first successful laser developed by Maiman in 1960.
A photodiode is a semiconductor device that converts light into an electrical current. The current is generated when photons are absorbed in the photodiode. Photodiodes may contain optical filters, built-in lenses, and may have large or small surface areas.
A photodiode is a semiconductor device that converts light into an electrical current. The current is generated when photons are absorbed in the photodiode. Photodiodes may contain optical filters, built-in lenses, and may have large or small surface areas.
Optoelectronics is the communication between optics and electronics which includes the study, design and manufacture of a hardware device that converts electrical energy into light and light into energy through semiconductors. This device is made from solid crystalline materials which are lighter than metals and heavier than insulators. Optoelectronics device is basically an electronic device involving light. This device can be found in many optoelectronics applications like military services, telecommunications, automatic access control systems and medical equipments.
Laser Action
The combination of spontaneous emission first, and then stimulated emission, causes the laser to "lase," which means it generates a coherent beam of light at a single frequency.
A seven-segment display is a form of electronic display device for displaying decimal numerals that is an alternative to the more complex dot matrix displays. Seven-segment displays are widely used in digital clocks, electronic meters, basic calculators, and other electronic devices that display numerical information.
Haemodialysis is a way of replacing some of the functions of your kidney, if your kidneys have failed, by using a machine to filter and clean your blood. Blood is pumped out of your body to the machine where it is passed through a series of tiny tubes, in an 'artificial kidney' or 'dialyser'. In haemodialysis your blood flows out of your body, round a dialysis machine and through a dialyser. The dialyser cleans your blood of waste products and then it is returned to your body. The haemodialysis process replaces the cleaning function normally carried out by healthy kidneys.
A pacemaker is a small device that's placed in the chest or abdomen to help control abnormal heart rhythms. This device uses electrical pulses to prompt the heart to beat at a normal rate.Pacemakers are used to treat arrhythmias (ah-RITH-me-ahs). Arrhythmias are problems with the rate or rhythm of the heartbeat.Typically, people who have had a pacemaker fitted are advised to take 3 to 7 days off.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
How to Split Bills in the Odoo 17 POS ModuleCeline George
Bills have a main role in point of sale procedure. It will help to track sales, handling payments and giving receipts to customers. Bill splitting also has an important role in POS. For example, If some friends come together for dinner and if they want to divide the bill then it is possible by POS bill splitting. This slide will show how to split bills in odoo 17 POS.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
How to Create Map Views in the Odoo 17 ERPCeline George
The map views are useful for providing a geographical representation of data. They allow users to visualize and analyze the data in a more intuitive manner.
The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
For more information, visit-www.vavaclasses.com
Chapter 3 - Islamic Banking Products and Services.pptx
Optoelectronics
1.
2. OPTOELECTRONIC
Optoelectronics is an interesting branch of electronics that combines both electronics
and optics.
Optoelectronics is the study and application of electronic devices that interact with
light.
Optoelectronic devices find varied applications in telecommunications, military services,
medical field, and automatic control systems.
2
5. LIGHT EMITTING DIODE
LED is an optical diode == it emits light when FB
Symbol is similar to PN Junction diode apart from two arrows indicates
- device emits the light energy
Basic operation :
Pn junction is in forward bias = electron in N type cross the Jn & recombine with
hole in P type semiconductor material
Free electrons are in the conduction band and at a higher energy than the holes in
the valence band.
When free electron combine with holes, it fall from CB to VB === energy level
changed from high value to low value
The difference in energy between Higher level and lower level is released in the
form of photon( emits light energy)( due to some material) ( normal diode = heat)
such diodes = LED = process called electroluminescence 5
6. LIGHT EMITTING DIODE
Energy released in the form of light depends on the energy corresponding to forbidden
gap. Determines the wavelength of the emitted light.
wavelength determines colour of the light. Also determines light is visible or invisible(IR)
Various impurities are added during the doping process to control the wavelength &
colour of the emitted light
6
7. LIGHT EMITTING DIODE
Normal Silicon diode, FG = 1.1ev , wavelength of emitted light correspond to IR light
spectrum. == light is not visible.
Materials used in LED
GaAs, GaAsP or GaP (mixures of elements gallium, arsenic and phosphorus)
GaAs - Infrared radiation (Invisible)
GaAsP - Red or yellow light
GaP - Red or green light
Some LEDs- blue & orange light(InGaN)
LEDs emit no light when reverse biased. Operating LED in reverse direction will quickly
destroy them
7
8. LIGHT EMITTING DIODE
Construction of LED
Deposit three semiconductor layers on the substrate
Action region = between p type & n type regions = active region
emits light
During FB, Holes from P type recombine with Electrons from N
type in the active region = light is emitted
LED emit light all the way around the layered structure. So placed
the entire system in the tiny reflective cup so that the exit light
reflected towards the desired direction.
8
9. LIGHT EMITTING DIODE
LED : voltage & current
Resistor = Rs = current limiting resistor = current is limited ( not
exceeding the maximum current rating of the diode)
VS = Supply voltage
VD = voltage drop across LED
Apply KVL to the circuit
VS = IS RS + VD
IS = VS - VD
RS
9
Voltage drop in LED > Voltage in normal diode
Voltage drop = 2 to 3 V
Current range = 10 to 80 mA
Reverse break down voltage << normal diode
Reverse break down range = 3V to 10 V
10. LIGHT EMITTING DIODE
Spectral output curves
Visibility of light = decided by the wavelength
Graph = output light Vs wavelength(nm) = spectral curve
peak at 460nm(blue), 540nm(green), 590nm(yellow) and 660nm(red)
Infrared visible light peak at 940nm
10
11. LIGHT EMITTING DIODE
Radiation Pattern of LED
LED = directional light source
it emits light in a particular way which has a typical radiation pattern
most of the energy emitted within 20˚ of the direction of maximum light
Some LEDs = plastic lens = spread the light to greater angle to increase the
visibility
Coloured lens are also used = to
enhance the colour
11
12. LIGHT EMITTING DIODEAdvantages :
Small in size
Brightness controlled by varying current
Fast operating devices
light in weight
Available in various colours
Have long life
Cheap and readily available
Easy to interface to various electronic devices
used in Burglar alarm system
12
Disadvantages :
Luminous efficiency is low
Characteristics affected by temp
Frequent replacement of battery
need large power for its
operation
Applications :
Sensor Applications
Sign Applications
LED Signals
Mobile Applications
Indicators
