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. Q.5. What does the laser wavelength depends upon ? Why is Schottky diode called hot-carrier diode? Because of very low capacitance, point contact diode is very much suitable for high freuency applications (of the order of 10 GHz). The leads of an LED should never be bent closer than about 2 mm from the encapsulation. Material dispersion occurs because the index of refraction varies as a function of the optical wavelength. This is also called a unilateral diode. 26. Physics Lab(15PHYL17/27) Viva Questions: EXPERIMENTS: 1. 3. 41. Because a photodetector converts the received optical power directly into an electric current output (photo current) ? 12. Viva Voce Questions on Polarimeter . 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. What is the basic structure of a modern optical fiber? What are the difference between LED and Laser diode? How the voltage variable capacitance varies with the change in voltage across it? 34. on: "Optical Communication Lab - Viva Questions". 13. Previous Year Examination Questions 1 Mark Questions. InGaAs. Semiconductor Laser Amplifier (SLA), Fiber Raman Amplifier (FRA), Fiber Brillouin Amplifier (FBA), Rare Earth ion Doped Fiber Amplifier. What is a zener diode? Dispersion is defined as the pulse spread as function of wavelength. Laser wavelength depends upon the selection of the materials and their energy gap. 19. Preparing for your viva. Name The Breakdown Mechanism In A Highly Doped P-n Junction Under Reverse Biased Condition. Zener diode is a p-n junction diode specially designed for operation in the breakdown region in reverse bias condition. 36. This material can absorb light with wavelength as long as 1650 nm. 32. Try to anticipate questions, comments and criticisms, and think how you would respond. (vi) Core refractive index profile (step index or graded index). The junction barrier is called the Schottky barrier. What are the two main causes of intramodal dispersion ? What do you mean by numerical aperture of an optical fiber? Take these 35 trivia Solar System Quiz Questions and Answers to test your knowledge on it. Your email address will not be published. Give examples? An avalanche diode is a one kind of diode that is designed to experience an avalanche breakdown at a particular reverse bias voltage. 21. Give two applications of solar cell in daily life. 34. 1. 25. In this pattern, the source is equally bright when viewed from any direction. (iii) A larger core radii of multimode fibers makes launching optical power into the fiber easier. 3. Light is an electromagnetic radiation with a much shorter wavelength and higher frequency than radio waves. 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). Mention the applications of DIAC, SCR, LED and photoconductive cell. 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. Its symbol is. What Is Cut-off Frequency? Award of PhD recommended subject to no or minor corrections. The core and the cladding have different optical characteristics. Detection of light is a basic need for everything like plants, animals and even devices. 0.1 V B. 5. Some questions for viva voce examination: Q.1 What is photoelectric effect? Dr. B Somanathan Nair, one of the top engineering text book author of India. 14. 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. A photodiode is a semiconductor device that converts light into an electrical current.The current is generated when photons are absorbed in the photodiode. Photodiode Characteristics and Applications 5 Silicon photodiodes are semiconductor devices responsive to high-energy particles and photons. LEDs should neither be reverse-biased nor operated near their maximum current rating. Define what is zener voltage? What are the advantages offered by multimode fiber than a single mode fiber? Light Emitting Diode or LED objective questions and answers. Required fields are marked *. As this is usually a favourite opening question with the aim of getting you to relax with something familiar. 21. Home » SPECIAL PURPOSE DIODES Questions » 300+ TOP SPECIAL PURPOSE DIODES Questions and Answers pdf. 29. 37. Is there any difference between photodiode … Energy Gap Experiment Practical Arabic YouTube. 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. Single mode lasers contain only a single longitudinal mode and a single transverse mode. 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. Why is photodetector called a square law device ? 26. The photoelectric effect cannot be explained by considering light as a wave. 42. It has no storage charge. Define quantum efficiency of a detector. (adsbygoogle = window.adsbygoogle || []).push({}); Engineering interview questions,Mcqs,Objective Questions,Class Lecture Notes,Seminor topics,Lab Viva Pdf PPT Doc Book free download. 0.26 V C. 1.1 V D. 2 V Define what is a step-recovery diode and why is it so called ? Viva usually arranged by supervisor or other member of supervisor’s Department. The core and the cladding have different optical characteristics. The modern optical fiber consists of an optical rod core coated with a cladding. A. Q.2 What is a photo cell? This set of Linear Integrated Circuit Multiple Choice Questions & Answers (MCQs) focuses on “Ideal Operational Amplifier”. 33. 2. 35. 38. Black box experiment; Identification of unknown passive electrical components and determine the value of Inductance and Capacitance 2. ... Optical Communication  Lab -  Viva Questions  With Answers 1. The most obvious form of preparation is to re-read your thesis. In my experience, when I ask what is electronics there is a tendency for many ones... 8085 Microprocessor Lab Viva Questions  With Answers 1. Q.4 Which type of the cell is a solar cell? How is the frequency response of an LED limited? Since photodiodes output a current, the saturation limit can be adjusted by modifying the reverse bias voltage (within specification) or … This article discusses about a brief information about the construction and working of an avalanche diode. Step-recovery diode is a voltage-dependent variable capacitor diode with graded doping profile (concentration of charge carriers decreasing near the junction). 47. The classic starter question to summarise your research. The isotropic pattern from a surface emitter is called Lambertian pattern. 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. This property of zener diode makes its use as a voltage regulator. What do you mean by the cut off condition ? Photodiode is a photovoltaic device as well as a photoconductive device. The varactor diode produces voltage variable capacitor. This generated EMF is proportional to the frequency and intensity of the incident light. What is the difference between photovoltaic mode and photoconductive mode of operation of photo diode? Explain how zener diode maintains constant voltage across the load? 15. Define what happens to the series current , load current and zener current when the dc input voltage of a zener regulator increases? Explaining the Photoelectric Effect: The Concept of Photons. A. Power diodes find many applications in electronics and electrical engineering circuits.’. Thus zener diode maintains voltage constant across the load. Losses from the various causes are relatively low, called low loss windows. What is meant by the temperature coefficient? What are the two principal photo detectors used in a fiber optic line? V-I characteristic of Photo diode ? What are the types of optical amplifiers available? Because of step or sudden recovery from the reverse current ON to reverse current OFF, it is called the step-recovery diode. 1. 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. Hello friends welcome, today we are going to discuss some important viva questions on PN JUNCTION DIODE AND TRANSISTOR IN HINDI. Photodiode is a two-terminal semiconductor p-n junction diode device and is designed to operate with reverse bias. 2. what's difference in normal diode & photo diode ? Series and parallel LCR Circuits (Determination of resonant frequency and quality factor) 3. 50 TOP SEMICONDUCTORS PN JUNCTION Theory Questions And. G-R-j=0, where j is the current extracted from the material. 11. 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. 17. But this sort of question also applies for each chapter in your thesis. 31. Viva Voce Questions on Polarimeter . 39. 6. It is a quantum mechanical phenomena and comes in discrete particles called Photons.A light sensor is a passive s… 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 the photodiode as the incident optical power increases. 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. Principle of Photo diode ? 8. The voltage at which the zener diode breaks down is called the zener voltage. 32. Define internal quantum efficiency of an LED? Question 7. A typical output of a solar cell is . ZENER DIODE LAB VIVA Questions :-1. 2. 43. 45. What are low loss windows? If the radiative recombination rate per unit volume is R. Intermodal dispersion : Dispersion caused by the delay between different modes. 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. 1. Which are the different types of fibers? DIAC: 1. Schottky diode is uite different in construction from the normal p-n junction diode. Experiment Questions: 1.Experimently find out whether the given diode is made of Germanium or Silicon. Question 6. Question 8. What are the advantages of plastic fiber? I–V Characteristics of Zener 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. 2. 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. 2 general application of Photo diode ? Security sy… On ruled part start writing the experiment, (Aim, Apparatus, Significance, Theory etc.) Viva Question For Band Gap Physics Lab – Viva Voce Believe Achieve DVRCET. The Viva itself. Your email address will not be published. Question 6. 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