Skip to main content

खनन और खनिज उद्योगों में पर्यावरणीय स्थिरता विषय पर विशेषज्ञों का मंथन

खनन और खनिज उद्योगों में पर्यावरणीय स्थिरता  विषय पर विशेषज्ञों का मंथन पर्यावरणीय स्थिरता मानव समाज के निरन्तर अस्तित्व, समृद्धि और स्वास्थ्य के लिए मूलभूत शर्त है। हमारी न्यू जनरेशन को स्पीड और टेक्नोलॉजी पर ध्यान केंद्रित करना होगा ताकि भविष्य को सुनहरा बनाया जा सके। उक्त विचार मुख्य अतिथि श्री एमपी सिंह, प्रधान मुख्य अभियंता, केंद्रीय विद्युत प्राधिकरण विद्युत मंत्रालय भारत सरकार, नई दिल्ली ने व्यक्त किए श्री सिंह भूपाल नोबल्स स्नातकोत्तर महाविद्यालय में भूविज्ञान विभाग द्वारा "खनन और खनिज उद्योगों में पर्यावरणीय स्थिरता" विषय पर आयोजित दो दिवसीय राष्ट्रीय कॉन्फ्रेंस के समापन पर बोल रहे थे। दो दिवसीय राष्ट्रीय कान्फ्रेंस का भव्य समापन सम्मानित अतिथि प्रो विनोद अग्रवाल सदस्य, भारत सरकार नई दिल्ली स्थित MOEFCC की विशेषज्ञ मूल्यांकन समिति, (सि एण्ड टीपी) अपने उद्बोधन में कहा कि पर्यावरण स्थिरता सरकार और समाज दोनों की जिम्मेदारी है। वर्तमान में खनन उद्योग विभिन्न प्रावधानों एवं कानूनों के तहत कार्य कर रहा है ताकि पर्यावरण को सुरक्षित रखा जा सके। आयोजन सचिव डॉ. हेमंत सेन न...
Post a Comment

Light emitting diode | Electronics | Semiconductor diode

Optoelectronic diode

  • An optoelectronic diode is a diode which includes optics along with electronics. It means optoelectronic diode either emit light or they work when light falls on them.
  • Here we will discuss about light emitting diode as an optoelectronic diode.

Light emitting diode (LED)

Principle of LED

  • In simple p-n junction diodes (Ge, Si), the energy bands are indirect.
  • When these diodes are forward biased, then the recombination of electron-holes across the junctions starts.
  • When electron jumps from higher energy level to lower energy levels then the energy emitted by electrons in these diode will be in the form of heat and hence we can not see it.
  • In some semiconductor (GaAs), the energy bands are direct.
  • When these semiconductor diodes are forward biased then in the process of recombination of electron-hole pairs, the electron jumps from higher energy level to lower energy levels.
  • The energy emitted during this process lie in the visible region, and it is clearly seen due to transparent material of the crystal.
  • Since these diodes emit light energy on forward biased, hence they are known as light emitting diode.

Construction of LED

Light emitting diode (a) Arrangement and (b), (c) Circuit symbol
  • In LED generally we use GaAs or In-P.
  • In these diodes n-type semiconducting layer grow on a p-type substrate by diffusion.
  • After it a thin layer of p-type material is grow up on n-type layer.
  • At the external sides of these layers a thin metallic contacts are attached, which are connected to cathode (K) and anode (A) respectively.
  • The whole arrangement is placed in a transparent plastic cover or envelope.
  • The colour of plastic cover depends on the light emitted by diode.
  • It is used in low forward bias.
  • The wavelength (colour) emitted by the diode depends on the the % error of As in GaAS-P diode.
  • Common formula for it is GaAs1-x Px.
  • GaAs gives I.R. light and GaP gives light of blue colour.
  • If the energy band of above diode is 1.8 eV, we get light of red colour.
  • If this diode is doped with nitrogen we get light of all the colours ranging from yellow to green in visible region.
  • Wavelength of emitted light
                λ= hc / Eg = (1.26 / Eg) μm
  • Here h = Planck's constant, c = velocity of light and Eg = energy gap between valence band and conduction band.
  • If we join seven segment of LED, then we can get any number from 0 to 9. Here a number 4 and number 8 are shown.
Seven segment LED

Uses of LED

  • LED is used in calculators.
  • It is used in watches.
  • LED is also used in platform signals.
  • Light emitting diode is also used as a pilot lamp in electronic device for showing on-off position.
  • Theses diodes are also used in optical communication systems.
To know more about light emitting diode (LED) please click on the link https://youtu.be/EyTUJV-NXH0  for English and on https://youtu.be/WuOKbuHpq1Q  for bilingual (Hindi/English)
Labels:

Comments

Post a Comment

Popular posts from this blog

Electric field due to circular loop of charge | Electromagnetics

Electric field due to circular loop of charge Electric field The space around a charged particle in which another charge experience a force is known as electric field. The source of electric field is either a charge or a time varying magnetic field. If the value of electric field does not change with time, then it will be uniform electric field, otherwise it will be non-uniform electric field. Electric field due to circular loop of charge If λ is linear charge density, then the charge on d l dq = λ d l      ⇒     dq = (q / 2πa) d l Electric field at P due to charge dq Special cases When P lies at the centre of the loop i. e., r = 0, then E = 0 When P lies very far from the centre of the loop i. e., r >> a, then E = kq / r 2 In this case circular loop behaves as a point charge. To know more about this topic please click on the link  https://youtu.be/54MIe0Ow43w   or...
Post a Comment
Read more

American Activity in Venezuela: A Simple Guide for Students

American activity in Venezuela is an important topic in international relations. It includes political involvement, economic decisions, oil interests, and humanitarian support. This blog explains the topic in simple terms for students. History of U.S.–Venezuela Relations For many years, the United States and Venezuela shared friendly relations. Venezuela was a major supplier of oil to the U.S., and many American companies invested in Venezuela’s oil industry. These strong economic ties helped both countries grow. Impact of Hugo Chávez on U.S.–Venezuela Relations In 1999, Hugo Chávez became the President of Venezuela. His socialist ideas and strong opposition to U.S. influence changed the relationship. He reduced the role of American companies and strengthened ties with countries that opposed U.S. policies. This marked the beginning of political tension. U.S. Political Involvement in Venezuela The United States claims that its actions in Venezuela are aimed at supporting democracy...
Post a Comment
Read more

Thomson’s parabola method | EMFT and Relativity | Motion of charged particles in E and B fields

Thomson’s parabola method Positive ray analysis This method is used to find the charge to mass ratio. Thomson parabola method T = Discharge tube, the pressure of gas in this tube is kept 0.01 mm of Hg E = Capillary tube C = Cathode, which is perforated with an extremely small holes W = Water jacket, used to cool the cathode A and B = Metallic plates, the electric field is applied between these plates N and S = North and south poles of a heavy magnet K = Highly evacuated camera P = Photographic plate R = Liquid air trap, used to keep the pressure in K quite low Working To ensure the supply of the gas, a steady steam of the gas is allowed to pass through E and after circulating the tube, it is escaped through M. The positive ion produced in T move towards C. The ion which reaches C axially. pass through its fine hole in the form of narrow beam. After crossing C, the parallel beam of ions enters into the electric and magnetic...
Post a Comment
Read more