What are the advantages of plastic fiber? Optical Communication Lab - Viva Questions With Answers. Schottky diode is uite different in construction from the normal p-n junction diode. 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. Four Probe Method VIVA QUESTIONS BragitOff Com. 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. The isotropic pattern from a surface emitter is called Lambertian pattern. What do you mean by the cut off condition ? Here we are going to discuss about what is electronics. This article discusses about a brief information about the construction and working of an avalanche diode. It is a quantum mechanical phenomena and comes in discrete particles called Photons.A light sensor is a passive s… Ans. If the radiative recombination rate per unit volume is R. Intermodal dispersion : Dispersion caused by the delay between different modes. •Photodiodes saturate when the output photovoltage approaches the reverse bias voltage. Why is photodetector called a square law device ? Question 7. Classification, Elements, Configuration of Data Ac... Data Acquisition System with Block Diagram. Q. What are low loss windows? 46. 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. 45. An avalanche diode is a one kind of diode that is designed to experience an avalanche breakdown at a particular reverse bias voltage. Dr. B Somanathan Nair, one of the top engineering text book author of India. What precautions are reuired to be observed in the use of LEDs? Give a wavelength for the three low loss windows. 3. Its symbol is. V-I characteristic of Photo diode ? 4. 26. How the current is reduced to zero in a photodiode? (ii) Photo diode A photodiode is a special type of junction diode used for detecting optical signals. 10. Viva Question For Band Gap Physics Lab – Viva Voce Believe Achieve DVRCET. ... Optical Communication  Lab -  Viva Questions  With Answers 1. Required fields are marked *. The varactor diode produces voltage variable capacitor. Detection of light is a basic need for everything like plants, animals and even devices. Viva Voce Questions on Polarimeter . What do you mean by numerical aperture of an 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 : Zener breakdown. Which are the different types of fibers? Q.4 Which type of the cell is a solar cell? Photodiode is a photovoltaic device as well as a photoconductive device. 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. 21. The photoelectric effect cannot be explained by considering light as a wave. In dark, j=0, so G=R. No compromise to be made. 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. 6. 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. 14. 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. Why is Schottky diode called hot-carrier diode? 21. Card readers. Preparing for your viva. Consequently, the spectral width of the optical emission is very narrow. 19. What are the two principal photo detectors used in a fiber optic line? Define quantum efficiency of a detector. 31. This property of zener diode makes its use as a voltage regulator. 36. What are the types of optical amplifiers available? 50 TOP SEMICONDUCTORS PN JUNCTION Theory Questions And. Define internal quantum efficiency of an LED? 28. 11. 33. 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. 4. What are the characteristics needed for an LED to be used in optical communication? 25. 21. This is the constant of proportionality in the Stefan–Boltzmann law, Q.5. Why Security sy… anticipated questions and answers), although I … 1. Here are few probable Viva question on Photo diode . Figure 1. What are you doing ? Encoders where a rotating disc with light and dark stripes rotates - this gives speed and direction or rotation. What is the basic structure of a modern optical fiber? 37. 18. 34. A. The Viva itself. Solar Cell Multiple Choice Questions and Answers. 3. Since photodiodes output a current, the saturation limit can be adjusted by modifying the reverse bias voltage (within specification) or … It has no storage charge. The Viva Examiners viva student after a pre-viva meeting. Student makes corrections which are checked by examiners. Laser wavelength depends upon the selection of the materials and their energy gap. Define what is photodiode? 3. This is also called a unilateral diode. Previous Year Examination Questions 1 Mark Questions. 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. Because of very low capacitance, point contact diode is very much suitable for high freuency applications (of the order of 10 GHz). 35. In ‘on’ state , the voltage across zener diode remains constant until the voltage across it deops less than VZ . Q.3 Define the illuminating power and intensity of illumination. 34. 1. 15. 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? Home » SPECIAL PURPOSE DIODES Questions » 300+ TOP SPECIAL PURPOSE DIODES Questions and Answers pdf. Number of available carriers C. Type of semiconductor material used D. Number of recombinations taking place LED must have a high radiation output, a fast emission response time and a high quantum efficiency. 32. Zener diode is a p-n junction diode specially designed for operation in the breakdown region in reverse bias condition. What are the important CPU registers in the 8085 microprocessor? This set of Linear Integrated Circuit Multiple Choice Questions & Answers (MCQs) focuses on “Ideal Operational Amplifier”. The large magnitude of current in power diodes leads to ohmic drop that hides the exponential part of the V-I characteristic curve. 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. Q.2 What is a photo cell? What are the two main causes of intramodal dispersion ? The toughness and durability of plastic allow these fibers to be handled without special care. 40. Light is an electromagnetic radiation with a much shorter wavelength and higher frequency than radio waves. What is the difference between photovoltaic mode and photoconductive mode of operation of photo diode? Construction of LED, that is physical dimensions B. 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. 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. Because of step or sudden recovery from the reverse current ON to reverse current OFF, it is called the step-recovery diode. Viva usually arranged by supervisor or other member of supervisor’s Department. What are the advantages offered by multimode fiber than a single mode fiber? What are the difference between LED and Laser diode? The voltage at which the zener diode breaks down is called the zener voltage. 27. 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