Pn junction diode and its characteristics in chapter 1 understanding the pn junction, we have seen how a pn junction is formed from a ptype and ntype semiconductor. Each diode was investigated by plotting the iv curve using a precision sourcemeasurement unit b2902a and a laptop with the corresponding quick iv measurement software installed. They provide a lowcost and no frill method for voltage regulation. It has a particular voltage known as break down voltage, at which the diode break downs while reverse biased. Understand the behaviour of a diode under forward and reverse bias and be able to plot the iv characteristic of an ideal diode 3. Use the diode equation for that state to solve the circuit equations and find i d and v d 3. Dec 16, 2012 and the best rectifier is fullwave rectifier.
The forward current in the diode should not exceed 300. You can check out and keep the portable breadboards, vb106 or vb108, from the 111lab for yourself only one each please this is the first of three labs on basic semiconductor components. Zener diode is a pn junction diode specially designed for operation in the breakdown region in. The zener diode has a unique property that offers a simple, lowcost solution to this problem. Replace the procedure in experiment 3 with the following procedure 1 measure the voltage and current through a signal diode use a 1n4148 from your graymark kit these are also available in the instrument room. Often in the development of electronic circuits it is required that voltages be limited in some manner to avoid circuit damage. To verify the vi characteristics of pn junction diode and zener diode. Experimently find out whether the given diode is made of germanium or silicon. Introduction we have seen in a previous experiment that the resistance of both a photodiode and a phototransistor changes as the intensity of the light hitting the device.
Diodes task 1 introduction to diodes farrell 1 091914 overview of the diodes experiments this and the following experiments will explore the world of diodes. A pn junction is the metallurgical boundary between the n and pregions of a semiconductor crystal. To get familiar with working knowledge of the following instruments. The vi characteristic of zener diode indicates that characteristic of zener diode in forward bias is same as pn junction diode. Figure 4 circuit to obtain iv characteristics via oscilloscope. You diodes will use the bit bucket breadboarding system to build and test several dc and ac diode circuits. Zener diode and voltage stabilizer with a variable load name. Although there are many different types of diode which use the same basic structure of an area of ptype material meeting an area of ntype material, the different types are optimised to provide different characteristics which can be used in a variety of ways in many electronic. Write down all circuit equations and simplify as much as possible 2. Zener diode lab viva questions and answers pdf free download. The zener diode mainly operates in reverse biased condition.
Lab report zener diod free download as powerpoint presentation. To plot the vi characteristics of a zener diode in reverse wise. Zener diode, resistors, power supply, multi meter circuit diagram. We will first consider the iv characteristic curve of a standard diode that we can use in the classroom. The zener diode is used in its reverse bias or reverse breakdown mode, i. Experimental methods py2108 2 1 learning objectives the objectives of this practical section are to 1. Iv characteristics pn junction diode theory a semiconductor pn junction diode is a two terminal electronic device that allows current in only one direction. We use zener diodes for voltage regulation and voltage stabilisation. The diode is firmed by doping a semiconductor like silicon or germanium with. Simulator procedure as performed through the online labs select the characteristics of diode from the drop down list. Diodes are semiconductors that normally conduct current in only one direction. Help labs this lab is another that you can do in your dorm room, if you like.
Diode characteristics 2012 summary this experiment was set up to investigate the different properties and characteristics of several different types of diode. Zener diodes are normal pn junction diodes operating in a reverse biased condition. Physics 4700 experiment 3 diodes 1 measure and graph the. Diodes overview diodes are mostly used in practice for emitting light as light emitting diodes, leds or controlling voltages in various circuits. A zener diode is a special kind of diode which allows current to flow in the forward direction in the same manner as an ideal diode, but will also permit it to flow in the reverse direction when the voltage is above a certain value known as the breakdown voltage, zener knee voltage or zener voltage. In this experiment also we know the how to differentiate. Furthermore, the limiting or clipping of voltages can be. The graph shows the reverse vi characteristics of the given pn junction diode. The objective of this experiment is to become familiar with the properties and uses of diodes. Observation of characteristics of a zener diode debangshu mukherjee bs. The zener breakdown voltage is the minimum reverse biased voltage below which the diode blocks the reverse current. Diode experiment guide view experiment properties of semiconductor junction diodes and their applications view experiment diode background information.
The zener diode working principles and its various. Use a dc power supply, zener diode, resistors and multimeter. Silicon diode characteristics part 1 university of texas. Pn junctions consist of two semiconductor regions of opposite type. Voltage regulation using zener diodes bryan witherspoon november 8, 2008 abstract in digital or mixedsignal applications, there is a need to precisely regulate the voltage entering or exiting a circuit. We have also learned about diffusion current, depletion region. In reverse bias, a negligible constant current flow through the zener diode but the current becomes abruptly large at certain voltage. The diodes symbol is an arrow with a bar, the arrow indicates the direction in which positive forward current flows. The semiconductor diode is a widely used electronics component found in many electronic circuit designs today. A zener diode is constructed for operation in the reverse breakdown re gion. We will also perform a modified experiment 3 silicon diodeswritten by hambley for our textbook. They are also called pn diodes in analogy with vacuum diodes. Zener diode characteristics experiment 2018 youtube.
By adjusting the rheostat, voltmeter reading is increased from 0 and in each time note the corresponding reading in milliammeter. The critical parameter of this type of diodes is the zener breakdown voltage. While this might not seem like a useful property, it is actually extremely useful. Part bfrom both experiment we can conclude the diode can become insulator when inreverse biased and also can be a conductor when in forward biased because thatstime the resistance become low and can make the current easily flow trough diode. To analyze the input and output characteristics and to. From the iv characteristics curve above, we can see that the zener diode has a region in its reverse bias characteristics of almost a constant negative voltage regardless of the value of the current flowing through the diode. Recipe for solving diode circuits state of diode is unknown before solving the circuit 1. Experiment 6, photodiode and phototransistor current measurements.
Diode circuits tutorial pdf 25p this note covers the following topics. Linear circuits and superpositionon page 119, and, in particular. How do you construct the laboratory experiment that will allow you to make. Scribd is the worlds largest social reading and publishing site. Such junctions show a pronounced rectifying behavior. For instance, to invoke a 1n4148 diode from the builtin library, we use a command of the type dxxx a c d1n4148. For correct voltage regulation, we need to find out precisely what voltage should be across the zener diode. Definition a diode is a twoterminal electronic component that conducts electric current in only one direction. Zener diode experiment viva questions with answers characteristics mcqs interview questions. The circuit diagram to plot the vi characteristics of a zener diode is shown.
Zener doide is a special diode with increased amounts of doping. The experiments in this laboratory exercise will provide an introduction to. Zener diode is a pn junction diode specially designed to operate in the reverse biased mode. This is to compensate for the damage that occurs in the case of a pn junction diode when the reverse bias exceeds the breakdown voltage and thereby. In the case of normal diodes the diode damages at the break down voltage. Connections are made as shown in the circuit diagram. E ective v ripple mv peak v ripple mv calculated 12. Jan 27, 2018 zener diode characteristics experiment 2018.
Understanding of the operation of the zener diodes materials necessary for this experiment 1. Home zener diode viva questions 50 top zener diode lab viva questions and answers pdf. It is acting as normal diode while forward biasing. In experiment b, a 6v zener diode used is conducting the bulb comes on in reverse biased because the applied voltage is greater than its breakdown voltage and thus shows that the breakdown region is the region of operation of the zener diode. Figure 2 shows the positive forward bias needed to make the diode conduct, v d, and the peak inverse voltage rating of the diode, piv, beyond which the diode also conducts. Working of the zener diode is similar to a pn junction diode in forward biased condition, but the uniqueness lies in the fact that it can also conduct when it is connected in reverse bias above its threshold breakdown voltage. Understand the physics of a pnjunction and how a junction diode is created 2. Correspondingly, is there a way we could determine the type of breakdown action from experimental measurements on a zener diode.
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