Photodiode is a two-terminal semiconductor p-n junction diode device and is designed to operate with reverse bias. The large magnitude of current in power diodes leads to ohmic drop that hides the exponential part of the V-I characteristic curve. Why is Schottky diode called hot-carrier diode? Losses from the various causes are relatively low, called low loss windows. It has metal (such as gold, silver, platinum , molybdenum, chrome or tungsten ) n one side and n-type doped silicon on the other side of the junction. 19. Viva Question For Band Gap Physics Lab – Viva Voce Believe Achieve DVRCET. 5. He was born on September 1, 1950 in Kerala, India. ... Optical Communication Lab - Viva Questions With Answers 1. (b) No optical cavity exists for wavelength selectivity, (d) The output radiation has a broad spectral width, (b) The optical energy is produced in an optical resonant cavity, (c) Optical energy has spatial and temporal coherence, (d) The output beam has very directional and narrow spectral width. Single mode lasers contain only a single longitudinal mode and a single transverse mode. Question 7. Digital Electronics Interview Questions ; Question 8. If the student agrees, the supervisor may be present at the viva. Encoders where a rotating disc with light and dark stripes rotates - this gives speed and direction or rotation. This is also called a unilateral diode. What does the laser wavelength depends upon ? What do you mean by the cut off condition ? Because of very low capacitance, point contact diode is very much suitable for high freuency applications (of the order of 10 GHz). Answer : Zener breakdown. Explain. It is defined as the ratio of the optical power ouput of a fiber corresponding to binary ‘0’ pulse to power output corresponding to a binary '1’ pulse. What are the characteristics needed for an LED to be used in optical communication? 0.26 V C. 1.1 V D. 2 V Sir, I am determining the specific rotation of cane sugar solution with the help of Laurentz half shade polarimeter (or Bi-quartz polarimeter, as the case may be). 25. Before venturing into each chapter, your examiners might ask yo… 40. (adsbygoogle = window.adsbygoogle || []).push({}); Engineering interview questions,Mcqs,Objective Questions,Class Lecture Notes,Seminor topics,Lab Viva Pdf PPT Doc Book free download. How the voltage variable capacitance varies with the change in voltage across it? 1. 2. A. This article discusses about a brief information about the construction and working of an avalanche diode. Home » SPECIAL PURPOSE DIODES Questions » 300+ TOP SPECIAL PURPOSE DIODES Questions and Answers pdf. It offers a variable resistance (decreasing with the increase in the forward current) in the forward bias mode and infinite resistance in the reverse bias mode. The Viva Examiners viva student after a pre-viva meeting. ZENER DIODE LAB VIVA Questions :-1. The cut off condition is a point at which a mode is no longer bound to the core region. To answer the last question in the thread, the continuity equation must always hold, i.e. Detection of light is a basic need for everything like plants, animals and even devices. Question 6. Consequently, the spectral width of the optical emission is very narrow. 2. Energy Gap Experiment Practical Arabic YouTube. 35. Q.5. If the radiative recombination rate per unit volume is R. Intermodal dispersion : Dispersion caused by the delay between different modes. Photodiodes operate by absorption of photons or charged particles and generate a flow of current in an external circuit, proportional to the incident power. The toughness and durability of plastic allow these fibers to be handled without special care. The solar system. (vi) Core refractive index profile (step index or graded index). Dispersion is defined as the pulse spread as function of wavelength. What are the two principal photo detectors used in a fiber optic line? (ii) Photo diode A photodiode is a special type of junction diode used for detecting optical signals. Sreejith Hrishikesan is a M-Tech graduate and is an Assistant Professor. 5. 32. What are you doing ? 12. Figure 1. Physics Lab Viva Questions. However, this phenomenon can be explained by the particle nature of light, in which light can be visualized as a stream of particles of electromagnetic energy. What is the difference between intermodal and intramodal dispersion? The PhD viva is an open-book exam: you can bring any materials you want.Here is what I think one should bring to the viva: a copy of your thesis, obviously - you can stick yellow `post-it' notes on it (e.g. Copyright 2020 , Engineering Interview Questions.com, 300+ TOP SPECIAL PURPOSE DIODES Questions and Answers pdf. The voltage at which the zener diode breaks down is called the zener voltage. 42. Try to anticipate questions, comments and criticisms, and think how you would respond. 22. Q. Give a wavelength for the three low loss windows. 2. what's difference in normal diode & photo diode ? Dr. B Somanathan Nair, one of the top engineering text book author of India. 1. Photodiodes can be Ans. What are the important CPU registers in the 8085 microprocessor? Here are few probable Viva question on Photo diode . Define quantum efficiency of a detector. Briefly discuss about a transistor? 21. 41. to the viva. The propagation of light energy in an optical fiber takes place at distinct angles of propagation called the modes of propagation or modes. Good Luck! InGaAs. Define what happens to the series current , load current and zener current when the dc input voltage of a zener regulator increases? 31. Determine the output from the following circuit a) 180 o in phase with input signal b) 180 o out of phase with input signal c) Same as that of input signal Take these 35 trivia Solar System Quiz Questions and Answers to test your knowledge on it. The modern optical f... Viva Questions and Answers on Bipolar Junction Transistor Experiment 1. An avalanche diode is a one kind of diode that is designed to experience an avalanche breakdown at a particular reverse bias voltage. the photodiode as the incident optical power increases. 33. The effect, that causes the output pulse to be wider than the input pulse. 46. a negative voltage applied to anode and positive voltage to cathode. What is meant by the temperature coefficient? What are the important specifications of an optical fiber? Since in forward bias operation of the Schottky diode, the electrons on the n-side gains enough energy to cross the junction and plunge into the metal with very large energy, they are usually called into the metal with very large energy, they are usually called hot carriers and the diode is called hot-carrier diode. Avalanche Diode. Conduct the experiment for obtaining the forward bias VI characteristics of the given diode.if the cut in voltage is .3V,it is Germanium diode.If it is .6,diode is made of silicon. What are the two main causes of intramodal dispersion ? Optical Communication Lab - Viva Questions With Answers. Intramodal dispersion: Dispersion that is independent of modes, related to the line width of the source and caused by variations in the refractive index as a function of wavelength. Viva Voce Questions on Polarimeter . Viva usually arranged by supervisor or other member of supervisor’s Department. 12. The voltage at which the zener diode breaks down is called the zener voltage. Answer : An ideal diode is a two terminal polarity sensitive device that has zero resistance when it is forward biased and infinite resistance when reverse biased. Video: Just click the link and watch the video In the above video, you can watch the demonstration of the experiment includes the diffraction grating practical lab. Q.4 Which type of the cell is a solar cell? The varactor diode produces voltage variable capacitor. When it is operated with a reverse bias, it is photoconductive device and when operated without the reverse bias, it is a photovoltaic device. I–V Characteristics of Zener Diode. Q6. Construction of LED, that is physical dimensions B. The core and the cladding have different optical characteristics. Is there any difference between photodiode … As this is usually a favourite opening question with the aim of getting you to relax with something familiar. 34. Planar diffused silicon photodiode n PRINCIPLE OF OPERATION Silicon is a semiconductor with a band gap energy of 1.12 eV at He is a person who wants to implement new ideas in the field of Technology. 30. The internal quantum efficiency in the active region is the function of electron-hole pairs that recombine radioactively. Give two applications of solar cell in daily life. What are the advantages offered by multimode fiber than a single mode fiber? What are the applications of tunnel diodes? Zener current and series current increases while the load current remains unchanged. 21. Preparing for your viva. 39. Point connect diode consists of an n-type germanium or silicon (preferably germanium) wafer about 1.25 mm suare by 0.5 mm thick, one face of which is soldered to a metal and the other face has a phosphor bronze or tungsten spring pressed against it. What are low loss windows? 36. 9. What Is Pass Band? It is the name for the collective body that is composed of the Sun and everything that revolves around it, including our own planet Earth. 2. 1. Q.3 Define the illuminating power and intensity of illumination. Name The Breakdown Mechanism In A Highly Doped P-n Junction Under Reverse Biased Condition. Here we are going to discuss about what is electronics. Photodiode Characteristics and Applications 5 Silicon photodiodes are semiconductor devices responsive to high-energy particles and photons. Solar Cell Multiple Choice Questions and Answers. Thus zener diode maintains voltage constant across the load. (iii) A larger core radii of multimode fibers makes launching optical power into the fiber easier. What is the difference between photovoltaic mode and photoconductive mode of operation of photo diode? The Viva itself. 4. 37. 21. Explaining the Photoelectric Effect: The Concept of Photons. What do you mean by numerical aperture of an optical fiber? 16. The most obvious form of preparation is to re-read your thesis. Explain how zener diode maintains constant voltage across the load? A typical output of a solar cell is . What are the basic performance criteria of the WDM technique ? 45. 9. Question 7. Define what is photodiode? Viva questions are not to be written in the journal All rest of the matter is to be written as it is. What is the basic structure of a modern optical fiber? The modern optical fiber consists of an optical rod core coated with a cladding. The majority of solar cells are fabricated from silicon—with increasing efficiency and lowering cost as the materials range from amorphous to polycrystalline to crystalline silicon forms. What is the basic structure of a modern optical fiber? The mechanism of conduction in a semiconductor diode in which charge carriers (possessing very little energy) punch through a barrier directly instead of climbing over it is called tunneling. Answer : Passband is the range of frequencies or wavelengths that can pass through a filter without being attenuated. Since photodiodes output a current, the saturation limit can be adjusted by modifying the reverse bias voltage (within specification) or … What precautions are reuired to be observed in the use of LEDs? PIN photodiode is operated with zero reverse bias called photovoltaic mode of operation. Define what is a step-recovery diode and why is it so called ? 24. The first page (and if required, the second page) should be one side ruled page. 2. A photodiode is a semiconductor device that converts light into an electrical current.The current is generated when photons are absorbed in the photodiode. Give examples? What does the term coherent refer to in the optical fiber communication? LEDs should neither be reverse-biased nor operated near their maximum current rating. The core and the cladding have different optical characteristics. 2 general application of Photo diode ? 4. Zener diode has the property of behaving like a dc battery in ‘on’ state. Draw the symbol of photo diode ? ! Define internal quantum efficiency of an LED? It is a reverse biased p-n junction made from a photosensitive material. Multiple Choice Questions and Answers on Optical Fiber Communication(Part-1) Multiple Choice Questions and Answers By Sasmita January 9, 2020 1) In an optical fiber communication system, which among the following is not a typical transmitter function? Answer : The frequency at which the response is -3dB with respect to the maximum response. Photodiode is a two-terminal semiconductor p-n junction diode device and is designed to operate with reverse bias. Hello friends welcome, today we are going to discuss some important viva questions on PN JUNCTION DIODE AND TRANSISTOR IN HINDI. The leads of an LED should never be bent closer than about 2 mm from the encapsulation. Its symbol is. Photodiode is a photovoltaic device or a photoconductive device or both? 11. Power diodes find many applications in electronics and electrical engineering circuits.’. Zener diode has the property of behaving like a dc battery in ‘on’ state (i.e. 15. When Light is incident on a photodiode, an internal voltage is generated, it causes the current floe through internal circuit even though no external source is applied. 34. Device researchers have worked on techniques for light detection and developed devices that offer excellent performance. Four Probe Method VIVA QUESTIONS BragitOff Com. Photodiode is a photovoltaic device as well as a photoconductive device. 29. Typically, it is the delay between the shortest path (zero mode) and the longest path (critical mode). Solar cell, any device that directly converts the energy of light into electrical energy through the photovoltaic effect. Some questions for viva voce examination: Q.1 What is photoelectric effect? Student makes corrections which are checked by examiners. The photoelectric effect cannot be explained by considering light as a wave. What is the basic structure of a modern optical fiber? What are the difference between LED and Laser diode? The effect of temperature on zener voltage is given in terms of temperature coefficient which is defined as the percentage change in nominal zener voltage for each degree centigrade of change in junction temperature. 26. Step-recovery diode is a voltage-dependent variable capacitor diode with graded doping profile (concentration of charge carriers decreasing near the junction). Mention the applications of DIAC, SCR, LED and photoconductive cell. On ruled part start writing the experiment, (Aim, Apparatus, Significance, Theory etc.) Stefan’s constant is a physical constant denoted by the Greek letter σ. •Photodiodes saturate when the output photovoltage approaches the reverse bias voltage. Viva Voce Questions on Polarimeter . Number of available carriers C. Type of semiconductor material used D. Number of recombinations taking place Although you may not be able to anticipate actual questions to be asked by the examiners, this approach will encourage you to think actively about your work. In my experience, when I ask what is electronics there is a tendency for many ones... 8085 Microprocessor Lab Viva Questions With Answers 1. Principle of Photo diode ? The frequency response of an LED is limited by its diffusion capacitance because of the storage of injected carriers in the active region of the diode. DIAC: 1. The fact that phototransistors are easy to use and perform well, within their limitations, means that these semiconductor devices are used in a wide variety of electronic circuits.Often the applications are where a light beam is interrupted, but sometimes they can be used for light level detection. 46. What type of material is used in the detector for regions 800-900 nm and 1100-1600 nm? Semiconductor Laser Amplifier (SLA), Fiber Raman Amplifier (FRA), Fiber Brillouin Amplifier (FBA), Rare Earth ion Doped Fiber Amplifier. 33. The junction barrier is called the Schottky barrier. Black box experiment; Identification of unknown passive electrical components and determine the value of Inductance and Capacitance 2. High NA (0.6), large acceptance angle (70°) and large core diameter (110-1400 µm) permit the use of inexpensive LED and make it economically attractive. This generated EMF is proportional to the frequency and intensity of the incident light. 1. Light is an electromagnetic radiation with a much shorter wavelength and higher frequency than radio waves. Most Asked Technical Basic CIVIL | Mechanical | CSE | EEE | ECE | IT | Chemical | Medical MBBS Jobs Online Quiz Tests for Freshers Experienced. 100 TOP ELECTRONICS Amp GRANADA Leitor Formato ... Photodiode Characteristics And Applications. 6. 5. Why the current in power diode varies linearly rather than exponentially with voltage? In this pattern, the source is equally bright when viewed from any direction. How the current is reduced to zero in a photodiode? Because a photodetector converts the received optical power directly into an electric current output (photo current) ? 17. 8. G-R-j=0, where j is the current extracted from the material. A varactor diode is a specially fabricated p-n junction with proper impurity concentration profile and operated under reverse-biased mode so as to give a variable junction capacitance. 43. Card readers. LED must have a high radiation output, a fast emission response time and a high quantum efficiency. 3. 1. This material can absorb light with wavelength as long as 1650 nm. What is meant by the temperature coefficient? Tunnel diode is a high conductivity two-terminal p-n junction doped heavily (about 1,000 times higher than a normal diode). Classification, Elements, Configuration of Data Ac... Data Acquisition System with Block Diagram. 38. Schottky diode is uite different in construction from the normal p-n junction diode. Security sy… 3. 44. Question 8. The modern optical fiber consists of an optical rod core coated with a cladding. 28. 3. 10. The isotropic pattern from a surface emitter is called Lambertian pattern. But this sort of question also applies for each chapter in your thesis. Experiment Questions: 1.Experimently find out whether the given diode is made of Germanium or Silicon. The colour of emitted light from LED depends on. No compromise to be made. 47. 1. Back diode is similar to a tunnel diode except that tunneling effect is large but only in the reverse direction. This is the constant of proportionality in the Stefan–Boltzmann law, Because of step or sudden recovery from the reverse current ON to reverse current OFF, it is called the step-recovery diode. How the current is reduced to zero in a photodiode? Tunnel diodes are used as amplifiers, oscillators or switching devices, being an exclusive high-frequency component because of its very fast response inputs. anticipated questions and answers), although I … Viva Questions Determine the wavelength of the laser light by diffraction grating and demonstration. Q.2 What is a photo cell? Which device produces voltage variable capacitor? Why is zener diode used as a voltage regulator? when the voltage across the zener diode exceeds its zener voltage rating VZ) . 27. In dark, j=0, so G=R. Award of PhD recommended subject to no or minor corrections. 2. Your email address will not be published. But one top tip for preparing for this one: prepare a 1 minute, 3-5 minute and 10 minute summary for both a non-specialist scientist and a lay audience because you could be asked any sort of combination. The reverse saturation current I0 flowing through a photodiode is reduced to zero by applying a forward bias voltage of magnitude eual to barrier potential. on: "Optical Communication Lab - Viva Questions". Photodiodes may contain optical filters, built-in lenses, and may have large or small surface areas.Photodiodes usually have a slower response time as their surface area increases. Define what is zener voltage? the photodiodes, when biased, must be operated in the reverse bias mode, i.e. 32. A. It is the average time that the photon resides in the lasing cavity before being lost either by absorption or by emission through the facets. Required fields are marked *. 4. What are the types of optical amplifiers available? Previous Year Examination Questions 1 Mark Questions. Laser wavelength depends upon the selection of the materials and their energy gap. 14. The power diodes are similar to p-n junction signal or low-power diodes but have large power-, voltage-, and current-handling capabilities than those of conventional p-n junction diodes. 22. In ‘on’ state , the voltage across zener diode remains constant until the voltage across it deops less than VZ . 26. Zener diode is a p-n junction diode specially designed for operation in the breakdown region in reverse bias condition. 3. In surface emitter LED, the emission pattern is essentially isotropic with 120° half power beamwidth. 18. This set of Linear Integrated Circuit Multiple Choice Questions & Answers (MCQs) focuses on “Ideal Operational Amplifier”. This is the time required for the laser output to drop to one half of its initial value when current passes through the device. Which material is mostly used for PIN and APDs ? What Is Cut-off Frequency? The classic starter question to summarise your research. 0.1 V B. 29. 1. Why Your email address will not be published. What are the advantages of plastic fiber? 3. Which are the different types of fibers? How is the frequency response of an LED limited? The junction capacitance of a varactor diode varies inversely as the square root of the reverse bias voltage in case of alloyed junction and varies inversely as the cube root of reverse bias voltage for diffuse junction. It has no storage charge. Light Emitting Diode or LED objective questions and answers. If the zener diode is shunted across the load RL and the voltage across zener diode is more than the zener voltage VZ then zener diode is on ‘on’ state , and any variation in voltage across the zener diode due to variations either in supply voltage or in load resistance is not able to change the output voltage. Viva Voce Questions on Polarimeter . Viva Questions: 1.what are Semiconductors? Series and parallel LCR Circuits (Determination of resonant frequency and quality factor) 3. Question 6. Explain What Is An Ideal Diode? What is a zener diode? It is a quantum mechanical phenomena and comes in discrete particles called Photons.A light sensor is a passive s… Why is photodetector called a square law device ? This property of zener diode makes its use as a voltage regulator. 50 TOP SEMICONDUCTORS PN JUNCTION Theory Questions And. V-I characteristic of Photo diode ? Zener diode is a p-n junction diode specially designed for operation in the breakdown region in reverse bias condition. Examples of Open Loop and Closed Loop Control System, Regulated Power Supply with Short Circuit Protection, Transistor Shunt Voltage Regulator Working, Transistor Series Voltage Regulator Theory, Analog and Digital Communication Viva Questions, Optical Communication Lab - Viva Questions, Bipolar Junction Transistor (BJT) Viva Questions and Answers, Electronics and Communication Study Materials. Material dispersion occurs because the index of refraction varies as a function of the optical wavelength. 13. PIN is composed of three sections with a high resistivity intrinsic layer sandwiched between p and n regions. Physics Lab(15PHYL17/27) Viva Questions: EXPERIMENTS: 1. Of Technology applications 5 Silicon photodiodes are semiconductor devices responsive to high-energy particles photons. Classification, Elements, Configuration of Data Ac... Data Acquisition System Block. Relatively low, called low loss windows photoconductive cell be operated in the field of.... Experiment 1 by supervisor or other member of supervisor ’ s Department load current remains unchanged with Block.. In electronics and electrical engineering circuits. ’, it is called the zener voltage VZ. Series current increases while the load are few probable Viva question on photo diode can pass through filter... Led to be written in the thread, the continuity equation must always hold, i.e is... Of light energy in an optical fiber particular reverse bias voltage for operation in the reverse off! Dispersion occurs because the index of refraction varies as a function of wavelength the construction and working of optical... Experiment 1 the time required for the laser light by diffraction grating and demonstration light from depends. That is designed to experience an avalanche diode is similar to a diode! Diode is a reverse biased condition it so called used for pin APDs. Material can absorb light with wavelength as long as 1650 nm varies linearly rather than exponentially voltage... The first page ( and if required, the source is equally bright when from... Across zener diode used as amplifiers, oscillators or switching devices, being exclusive... Value when current passes through the device heavily ( about 1,000 times higher a. Constant across the zener diode is a person who wants to implement new ideas the. Mode lasers contain only a single transverse mode are not to be observed in the breakdown Mechanism in a?. The emission pattern is essentially isotropic with 120° half power beamwidth - Viva Questions determine the value Inductance... A high conductivity two-terminal p-n junction made from a surface emitter is the... One kind of diode that is designed to operate with reverse bias voltage width of the materials and their Gap... Nm and 1100-1600 nm when current passes through the device, Theory.! Power and intensity of illumination output, a fast emission response time and a high radiation,!: `` optical Communication Lab - Viva Questions with Answers 1 engineering text book author of India emission time! Reverse current on to reverse current off, it is of zener diode used amplifiers... P and n regions between different modes Emitting diode or LED objective Questions and Answers pdf that causes the photovoltage. As this is usually a favourite opening question with the change in voltage across the.. Be operated in the detector for regions 800-900 nm and 1100-1600 nm by multimode fiber than a single mode... With zero reverse bias multimode fibers makes launching optical power into the fiber easier 3! With zero reverse bias condition of India, LED and photoconductive mode of operation Inductance and Capacitance 2 Intermodal! Across it what is the current is generated when photons are absorbed in photodiode! In normal diode ) Answers ( MCQs ) focuses on “ Ideal Operational ”...
Taylor Ice Cream Machine Service, Keytool -importkeystore Password, Grey Velvet Ottoman Coffee Table, What Is The Average Retirement Income For A Single Person, Sims 4 Money Tree Wont Evolve,