A PN junction is formed by joining a P-type semiconductor with an N-type semiconductor. When joined, a depletion layer forms at the junction that acts as an insulator. When forward biased, current flows easily through the junction. When reverse biased, very little current flows due to the high resistance of the depletion layer acting as a barrier. PN junction diodes are used as rectifiers, switches, detectors, and light emitting diodes (LEDs) in electronic circuits.
On this presentation i describe all the features and types of diode. This presentation started from short but understandable history of diode or zener . How diode is working? Answer of this question also clear after read all this presentation.
On this presentation i describe all the features and types of diode. This presentation started from short but understandable history of diode or zener . How diode is working? Answer of this question also clear after read all this presentation.
Introduction
Semiconductor is a solid substance that has conductivity between that of an insulator and that of most metals, either due to the addition of an impurity or because of temperature effects. Devices made of semiconductors, notably silicon, are essential components of most electronic circuits.
Examples: Silicon, Germanium, Carbon
Intrinsic & Extrinsic Semiconductor
Semiconductors are mainly classified into two categories: Intrinsic and Extrinsic. An intrinsic semiconductor material is chemically very pure and possesses poor conductivity. It has equal numbers of negative carriers (electrons) and positive carriers (holes). Where as an extrinsic semiconductor is an improved intrinsic semiconductor with a small amount of impurities added.
The Doping of Semiconductors
The addition of a small percentage of foreign atoms in the regular crystal lattice of silicon or germanium produces dramatic changes in their electrical properties, producing n-type and p-type semiconductors.
Pentavalent impurities
Impurity atoms with 5 valence electrons produce n-type semiconductors by contributing extra electrons.
Trivalent impurities
Impurity atoms with 3 valence electrons produce p-type semiconductors by producing a "hole" or electron deficiency.
N-Type Semiconductor
The addition of pentavalent impurities such as antimony, arsenic or phosphorous contributes free electrons, greatly increasing the conductivity of the intrinsic semiconductor. Phosphorous may be added by diffusion of phosphine gas (PH3).
P-Type Semiconductor
The addition of trivalent impurities such as boron, aluminum or gallium to an intrinsic semiconductor creates deficiencies of valence electrons,called "holes". It is typical to use B2H6 diborane gas to diffuse boron into the silicon material.
Diodes
A device that blocks current in one direction while letting current flow in another direction is called a diode. Diodes can be used in a number of ways. For example, a device that uses batteries often contains a diode that protects the device if you insert the batteries backward. The diode simply blocks any current from leaving the battery if it is reversed -- this protects the sensitive electronics in the device.
In this PPT we will study about the Transistor , symbol of transistor , types of transistor, operation of transistor , configurations of transistor, advantages of transistor and limitations of transistor.
#physicspptclub #In this video we will study about the Transistor , symbol of transistor , types of transistor, operation of transistor , configurations of transistor, advantages of transistor and limitations of transistor.
#physicspptclub #physicsexperiments #solid state #magnetism #magneticmaterial #presentation #education #physicsfacts #scienceexperiment #presentation #education #physicsfacts #scienceexperiment #quantum #presentation #quantumphysics #bsc #msc #btech #diodecircuits #pnjunctiondiode #physicsfacts #characteristics #education #transistor #pnptransistor #npntransistor #solid state #magnetism #magneticmaterial #presentation #education #physicsfacts #scienceexperiment #presentation #education #physicsfacts #scienceexperiment #quantum #presentation #quantumphysics #bsc #msc #btech #diodecircuits #pnjunctiondiode #physicsfacts #characteristicsis #education #transistor #pnptransistor #npntransistor
The three terminals of the FET are known as Gate, Drain, and Source.
It is a voltage controlled device, where the input voltage controls by the output current.
In FET current used to flow between the drain and the source terminal. And this current can be controlled by applying the voltage between the gate and the source terminal.
So this applied voltage generate the electric field within the device and by controlling these electric field we can control the flow of current through the device.
Introduction
Semiconductor is a solid substance that has conductivity between that of an insulator and that of most metals, either due to the addition of an impurity or because of temperature effects. Devices made of semiconductors, notably silicon, are essential components of most electronic circuits.
Examples: Silicon, Germanium, Carbon
Intrinsic & Extrinsic Semiconductor
Semiconductors are mainly classified into two categories: Intrinsic and Extrinsic. An intrinsic semiconductor material is chemically very pure and possesses poor conductivity. It has equal numbers of negative carriers (electrons) and positive carriers (holes). Where as an extrinsic semiconductor is an improved intrinsic semiconductor with a small amount of impurities added.
The Doping of Semiconductors
The addition of a small percentage of foreign atoms in the regular crystal lattice of silicon or germanium produces dramatic changes in their electrical properties, producing n-type and p-type semiconductors.
Pentavalent impurities
Impurity atoms with 5 valence electrons produce n-type semiconductors by contributing extra electrons.
Trivalent impurities
Impurity atoms with 3 valence electrons produce p-type semiconductors by producing a "hole" or electron deficiency.
N-Type Semiconductor
The addition of pentavalent impurities such as antimony, arsenic or phosphorous contributes free electrons, greatly increasing the conductivity of the intrinsic semiconductor. Phosphorous may be added by diffusion of phosphine gas (PH3).
P-Type Semiconductor
The addition of trivalent impurities such as boron, aluminum or gallium to an intrinsic semiconductor creates deficiencies of valence electrons,called "holes". It is typical to use B2H6 diborane gas to diffuse boron into the silicon material.
Diodes
A device that blocks current in one direction while letting current flow in another direction is called a diode. Diodes can be used in a number of ways. For example, a device that uses batteries often contains a diode that protects the device if you insert the batteries backward. The diode simply blocks any current from leaving the battery if it is reversed -- this protects the sensitive electronics in the device.
In this PPT we will study about the Transistor , symbol of transistor , types of transistor, operation of transistor , configurations of transistor, advantages of transistor and limitations of transistor.
#physicspptclub #In this video we will study about the Transistor , symbol of transistor , types of transistor, operation of transistor , configurations of transistor, advantages of transistor and limitations of transistor.
#physicspptclub #physicsexperiments #solid state #magnetism #magneticmaterial #presentation #education #physicsfacts #scienceexperiment #presentation #education #physicsfacts #scienceexperiment #quantum #presentation #quantumphysics #bsc #msc #btech #diodecircuits #pnjunctiondiode #physicsfacts #characteristics #education #transistor #pnptransistor #npntransistor #solid state #magnetism #magneticmaterial #presentation #education #physicsfacts #scienceexperiment #presentation #education #physicsfacts #scienceexperiment #quantum #presentation #quantumphysics #bsc #msc #btech #diodecircuits #pnjunctiondiode #physicsfacts #characteristicsis #education #transistor #pnptransistor #npntransistor
The three terminals of the FET are known as Gate, Drain, and Source.
It is a voltage controlled device, where the input voltage controls by the output current.
In FET current used to flow between the drain and the source terminal. And this current can be controlled by applying the voltage between the gate and the source terminal.
So this applied voltage generate the electric field within the device and by controlling these electric field we can control the flow of current through the device.
This presentation gives a lot of information about
Semiconductor Devices.This is presented by Rajesh Kumar Sangani from Rajiv Gandhi University of Knowledge Technologies,Basar Dist
Adilabad,A.P,India.
Voltage multipliers are AC-to-DC power conversion devices, comprised of diodes and capacitors, that produce a high potential DC voltage from a lower voltage AC source. Multipliers are made up of multiple stages. Each stage is comprised of one diode and one capacitor.
During the growth of a competitive global environment, there is considerable pressure on most organisations to make their operational, tactical, and strategic process more efficient and effective.
An information system (IS) is a group of components which can increase the competitiveness and gain better information for decision making. Consequently, many organisations decide to implement IS in order to improve the effectiveness and efficiency of their organisations
Information systems have become a major function area of business administration. The systems, nowadays, plays a vital role in the e-business and e-commerce operations, enterprise collaboration and management, and strategic success of the business
Introducing higher dielectric constant (k > 10) insulators [mainly transition metal (TM) oxides] is therefore indispensable for the 70 nm technology node and beyond
TM silicates such as HfSiOx have been preferred because they have better thermal stability compared to their oxides. The dielectric constant of TM silicates is less than TM oxides but higher than silicon oxide.
Because thought underlies many human actions and interactions, understanding its physical and metaphysical origins, processes, and effects has been a longstanding goal of many academic disciplines including artificial intelligence, biology, philosophy, psychology, and sociology.
Our whole world is a reflection of our thought.
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.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
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.
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.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
2. P type and N type semiconductors, taken
separately are of very limited use.
If we join a piece of P type material to a piece
of N type material such that the crystal
structure remains continuous at the boundary,,
….. A PN JUNCTION is formed
3. It can function as ….
Rectifier ,
Amplifier ,
Switching
And other operations in electronic circuits.
4. A PN junction cannot be produced by simply
pushing two pieces together or by welding
etc…. Because it gives rise to discontinuities
across the crystal structure.
Special fabrication techniques are adopted to
form a P N junction
5. What is a PN Junction?
A PN junction is a device formed by
joining p-type ( doped with B, Al)
with n-type (doped with P, As, Sb)
semiconductors and separated by a thin
junction is called PN Junction diode or
junction diode.
6. Electronic Symbol …..the triangle shows indicated
the direction of current
P type N type
Depletion layer forms an insulator
between the 2 sides
7. In PN junction diode, N is at right and P is at left.
Majority carriers
N region -- electrons
P region -- holes
8. Formation of depletion layer
NO external connections:
the excess electrons in the N region cross the junction
and combine with the excess holes in the P region.
N region loses its electrons ……becomes + vly charged
P region accepts the electrons ……becomes -vly charged
At one point , the migratory action is stopped.
9. An additional electrons from the N region are
repelled by the net negative charge of the p region.
Similarly,
An additional holes from the P region are repelled by
the net positive charge of the n region.
Net result
a creation of a thin layer of each side of the junction
……….which is depleted (emptied) of mobile charge
carriers…. This is known as DEPLETION LAYER
..Thickness is of the order of 10-6meter
10. The depletion layer contains no free and
mobile charge carriers but only fixed and
immobile ions.
Its width depends upon the doping level..
Heavy doped……..thin depletion layer
lightly doped……..thick depletion layer
11. POTENTIAL BARRIER
The electrons in the N region have to climb the potential
hill in order to reach the P region
Electrons trying to cross from the N region to P region
experience a retarding field of the battery and therefore
repelled. Similarly for holes from P region.
Potential thus produced are called ..potential barrier
Ge..0.3 V Si ..0.7V
12.
13. PN junction can basically work in two modes, (A
battery is connected to the diode )
forward bias mode ( positive terminal
connected to p-region and negative terminal
connected to n region)
reverse bias mode ( negative terminal
connected to p-region and positive terminal
connected to n region)
14. Forward biased PN junction
It forces the majority charge carriers to move
across the junction ….decreasing the width of
the depletion layer.
15. Once the junction is crossed, a number of electrons
and the holes will recombine .
For each hole in the P section that combines with an
electron from the N section, a covalent bond breaks
and an electron is liberatyed which enters the positive
terminal
Thus creating an electron hole pair.
Current in the N region is carried by ….electrons
Current in the P region is carried by …. Holes.
16. Reverse biased pn junction
If the + of the battery is connected to the n-type and the –
terminal to the p-type,
the free electrons and free holes are
attracted back towards the battery, hence
back from the depletion layer, hence the
depletion layer grows.
Thus a reverse biased pn junction does not conduct current
17. Only the minority carriers cross
the junction constituting very low
reverse saturation current.
This current is of the order of
micro ampere.
18. VOLTAGE –CURRENT (V-I)
CHARACTERISTICS OF PN JUNCTION
DIODE
The curve drawn between voltage across
the junction along X axis and current
through the circuits along the Y axis.
They describe the d.c behavior of the
diode.
19. When it is in forward bias, no current
flows until the barrier voltage (0.3 v
for Ge) is overcome.
Then the curve has a linear rise and the
current increases, with the increase in
forward voltage like an ordinary
conductor.
20. Above 3 v , the majority carriers passing
the junction gain sufficient energy to
knock out the valence electrons and raise
them to the conduction band.
Therefore , the forward current
increases sharply .
21. With reverse bias,
potential barrier at the junction increased. …
junction resistance increase…and prevents
current flow.
However , the minority carriers are
accelarated by the reverse voltage resulting a
very small current (REVERSE CURRENT)
….in the order of micro amperes.
22. When revrese voltage is increased beyond
a value ,called breakdown voltage,the
reverse current increases sharply and
the diode shows almost zero resistance .It is
known as avalanche breakdown.
Reverse voltage above 25 v destroys the
junction permanentaly.
23. Working of a PN junction Current
I-V characteristic of
Reverse Bias a PN junction diode.
Forward Bias
Zener or Voltage
Avalanche
Breakdown
• PN junction diode acts as a rectifier as seen in the IV characteristic.
• Certain current flows in forward bias mode.
• Negligible current flows in reverse bias mode until zener or
avalanche breakdown happens.
Refer https://nanohub.org/resources/68 for a detailed discussion on operation of PN junction.
24. Thus the P N junction diode
allows the electrons flow only
when P is positive .
This property is used for the
conversion of AC into DC ,Which
is called rectification
25. Automatic switch
When the diode is forward bias ,the
switch is CLOSED.
When it is reverse biased , it is OPEN
27. APPLICATIONS
….as rectifiers to convert AC into DC.
As an switch in computer circuits.
As detectors in radios to detect audio
signals
As LED to emit different colours.