A zener diode is constructed for operation in the reverse breakdown re gion. Useful mathematical relations are shown and illustrated with plots. In this tutorial, we will examine the use of zener diode in pspice and learn about editing the properties of devices this tutorial is written with the assumption that you know how to do all of the basic things in. For the series diode configuration that follows, find the qpoint values and the voltage across v r by employing the diode characteristics also shown in the next figure. When a reversebias voltage is applied to a pn junction, the electric field in the spacecharge region is increases. A simple solar cell experiment the following experiment was performed using a commercial polycrystalline silicon solar cell with an active area of 8. Definition ptype semiconductor is suitably joined to ntype semiconductor,to conduct surface is called pn junction.
To study the voltage regulation in zener diode regulation circuit. Diode, resistor, variable dc power supply, milliammeter, voltmeter, rheostat and wire. Photodiode working principle, characteristics and applications introduction. The reverse current in a photodiode depends on the intensity of light falling on it or exposure of light. Zener diodes characteristics circuit symbol equivalent.
Forward biasing will cause a large i f with a rather small value of v f. To draw the characteristic curve of a zener diode and to. The forward and the reverse bias iv characteristics of cu ii complexnsi oi structure at room temperature given in fig. Zener diodes are normal pn junction diodes operating in a reverse biased condition. You will complete unit three and unit four in part 2 the next experiment.
Silicon, zener, led diode characteristics table of contents 1. In forward bias condition, current is constant until certain voltage is reached. Clampers are easily distinguished from clippers in that they include a capacitive element. In reverse bias, a negligible constant current flow through the zener diode but the current becomes abruptly large at certain voltage. Unlike ordinary pn junction diode, the reverse current in zener diode is measured using milliammeter due to the large flow of current. The photoresponse characteristics were measured using a halogen lamb. Calculate static and dynamic resistance of the zener diode in both forward and reverse biased conditions before, after break down voltages. The zener diode is a particular type of diode that solves this problem.
The zener diode is silicon crystal diode having a special reverse current characteristics. In experiment b, a 6v zener diode used is conducting. Zener diode as voltage regulator tutorial electronicstutorials. Zener diode, resistors, power supply, multi meter circuit diagram. Loadline analysis note that the qpoint can also be found by solving simultaneously the network equation and shockleys equation, but it will be complex mathematical computation example. Diodes which are designed with adequate power dissipation capabilities to operate in the break down region are called as break down or zener diodes. It is designed such that student can easily plot the forward and reverse characteristics of different diode. A zener diode is a heavily doped silicon crystal diode which allows current to flow in the forward direction in the same manner as an ideal diode. Diode characteristics and applications theory support s rs 2 of 18 diode characteristics a diode is a semiconductor device that will conduct well in one the zener diode uses a pn junction in reverse bias to make use of the zener effect, which is a breakdown phenomenon which holds the voltage close to a constant value called the zener voltage. Objective in this lab you are to measure iv characteristics of rectifier and zener diodes in both forward and reversebias mode, as well as learn to recognize what mechanisms cause current flow.
The intensity of the light was controlled by solar powermeter model tm206. Zener diode working, characteristics and application as voltage regulator. The zener diode operates just like the normal diode when in the forwardbias mode, and has a turnon voltage of between 0. Its characteristics are strongly temperaturedependent, so a diode. Calculation of currentvoltage characteristics of a cu ii. A typical damper will include a capacitor, diode, and resistor with some also having a dc battery. Diode characteristics 2012 summary this experiment was set up to investigate the different properties and characteristics of several different types of diode. The symbol of zener diode is similar to the normal pn junction diode, but with bend edges on the vertical bar. Apparatus a zener diode with small reverse breakdown voltage of about 6 volts, i. The critical parameter of this type of diodes is the zener breakdown voltage.
Lab report experiment no 02 objectives to study the. Kunot, member, ieee summarya new charge control model of a pn junction diode is introduced in which the reverse current ir as well as the forward current zp are related to the charge q stored in the base region by. The negative part of the voltage axis corresponds to when the diode is reverse biased and the positive part is when the diode is forward biased. The objective of this experiment is to study the performance and characteristic of fullwave rectifiers and dc power supplies utilizing zener diode as a voltage stabilizing device. In impatt diode extremely high voltage gradient is applied400kvcmwhich a normal which a normal pn junction cant withstand. It is the reverse biased havily doped silicon or germanium pn junction diode which is operated in the breakdown region where current is limited by both external resistance and power dissipation of the diode. Jan, 2015 pn junction diode characteristics lab expriment 1. It has a particular voltage known as break down voltage, at which the diode break downs while reverse biased.
This video lecture explains the vi characteristics of the zener diode. In the forward biased mode the zener diode operates as a pn diode. Therefore, it can be assumed that the device behaves as a schottky diode and the thermionic emission theory can be used to obtain electrical parameters of the device. Nvis 6501, experimentation with diodes is an ideal platform to enhance education, training, skills. When a junction diode is reverse biased, normally only a very small reverse saturation current flows. The parameter fc determines the diode potential assumed as a fraction 0 diode. In zener diode as the reverse voltage applied on pn junction is increased, a limit comes when the current increases abruptly from its cut off value and zen. Effect of indentation on iv characteristics of aungaas.
The graph shows the reverse vi characteristics of the given pn junction diode. Electronics tutorial about the pn junction diode and the vi characteristics of pn junction. When you take your measurements for this experiment, you will find the response of your. Jan 09, 2020 multiple choice questions and answers on semiconductor diode. Zener diode experiment viva questions with answers characteristics mcqs interview questions. 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. Hence the forward characteristic is the same for both pn junction diode and zener diode. The zener diode working principles and its various. In this lab you are to measure iv characteristics of rectifier and zener diodes in both forward and reversebias mode, as well as learn to recognize what mechanisms cause current flow in each region of diode operation. Let me just recall for a minute the characteristics of a zener diode. The vi characteristics of pn junction diode in forwarding bias are nonlinear, that is, not a straight line. The codes that represent zener diodes always begin with either of the letters bzx or bzy.
Voltagecurrent characteristics of a zener diode physics. In this lesson we define the zener diode and describe its characteristics. It also permits the current to flow in the reverse direction when the voltage is above a certain value known as the breakdown voltage. Find zener breakdown voltage in reverse biased conditions. Forwardbias diode characteristics in this pafrt of the experiment we will obtain sufficient data to plot the. Effect of indentation on iv characteristics of aungaas schottky barrier diodes ahmetfarukozdemira, adnancalikb,guvencankayac,osmansahina, andnazim ucara a department of physics, art and science faculty, suleyman demirel university, isparta, turkey. You may assume the diode is on, and then find the current in the diode.
To draw the characteristic curve of a zener diode and to determine its reverse breakdown voltage aim to draw the characteristic curve of a zener diode and to determine its reverse breakdown voltage. Silicon diode characteristics part 1 university of texas. The operating characteristics of a diode can be illustrated with a graph of the current through the diode plotted against the applied voltage. Unit activity one diode properties two leds and zener diode three rectify a sine wave four basic power supply in the first unit you will investigate the general properties of a diode.
Zener diode is a pn junction diode specially designed to operate in the reverse biased mode. We have also learned about diffusion current, depletion region. Experiments 8 experiment 1 10 study of vi characteristics of silicon diode experiment 2 study of vi characteristics of zener diode experiment 3 16 study of vi characteristics of light emitting diode led 4. Introduction to light emitting diode technology and applications gilbert. Zener diode is a special kind of diode which permits the flow of current in the forward direction as well as in reverse direction when the voltage is above a certain voltage known as breakdown or zener voltage. Zener diode vi characteristics reverse characteristics of zener diode ideal zener diode equivalent circuit model practical zener diode equivalent circuit model in rbr. The performance of the fullwave rectifier will be studied and measured as well as that of the zener diode. This is a complete system to study the diode characteristics. Zener diodes are heavily doped than ordinary diodes. Investigating the iv characteristic of a diode in the real world of electronics, the current in a component is often calculated from the voltage drop across a resistor in series with it. Photodiode working principle characteristics and applications. If you need to use your diode on another day, mark it with a piece of tape with your name and leave it in the storage cubbies in the back of the lab. It is a silicon or germanium pn junction diode which is photosensitive in reverse bias condition.
Zener diode as voltage regulator and its vi characteristics. Zener diode is a pn junction diode specially designed for operation in the breakdown region in zener diode lab viva questions and answers pdf free download. In the case of normal diodes the diode damages at the break down voltage. 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. This was a bad thing before the whole avalanche breakdown, large current. The vi characteristic of zener diode indicates that characteristic of zener diode in forward bias is same as pn junction diode. The segment of the nanowire exposed to air is kept fixed at 400 nm, while the portion buried in bcb is varied between 300 and 600 nm. When the reverse voltage is sufficiently increased, the junction breaks down and a large reverse current flows. Does anybody know how to measure currentvoltage characteristics of a diode using arduino with 10 or higher bit resolution. Since the zener diode s reverse bias characteristics are what is needed to regulate the voltage, it is connected in reversed bias mode, with the cathode being connected to the positive rail of the circuit. Oct 16, 2014 an experiment to determine the iv characteristics of a semiconductor diode. Let us learn about this exciting and unique kind of diode.
In addition to reading the questions and answers on my site, i would suggest you to check the following, on amazon, as well. Therefore, knee voltage and forward resistance can be determined as explained in the previous experiment. In this region the voltage across zener diode remains constant but current changes depending on the supply voltage. Zener diode characteristics and zener as voltage regulator. Sign in to view the content sakshat amrita virtual lab. Analysis and characterization of pn junction diode switching a. Because diodes of the same type can have significantly different characteristics, use the same diode for all experiments in this lab. Let vcc be the dc voltage source to be used in the experiment.
We use zener diodes for voltage regulation and voltage stabilisation. Shahram marivani fullwave rectifiers and power supplies. Dynamic resistance of a pn junction diode is the small change in forward voltage to small change in forward current at a particular operating point. Multiple choice questions and answers on semiconductor diode. Photoelectrical characterization of a new generation diode. Simulator procedure as performed through the online labs select the characteristics of diode from the drop down list. Sep 12, 2015 zener diode iv characteristics curve in the forward bias condition, the zener diode behaves like an ideal diode within specified current and power limits, but it differs in reverse bias condition where the zener diode has very steep avalanche characteristic at the breakdown voltage in reverse bias condition. What is the value of the zener voltage for a given zener. To study and measure the effects of forward and reverse bias on the zener diode. Experimentation with diodes experiment electronics lab. To construct a zener voltage regulator and experimentally determine the range over which the zener maintains a constant output voltage.
The early history of zener diode clarence melvin zener inventor of zener diode. Vi characteristics of zener diode vi characteristics of. The forward and reverse bias characteristics of germanium diode are similar to those of a silicon diode, with some important differences. With your lab partner, brainstorm on the following ideas. Reverse breakdown is usefully applied in zener diodes. Reverse biasing will generally not cause current conduction until. The active portion of a zener diode is a semiconductor pn junction.
If the current flows into the positive terminal of the diode, then the assumption is right, otherwise, the diode is off. Hbd854 zener theory and design considerations handbook. It is acting as normal diode while forward biasing. A photodiode is a pnjunction diode that consumes light. Only when the need for semi conductor materials exceeded, the urge to develop a device like zener diode spread deeper and wider. An experiment to measure the ivcharacteristics of a silicon. The gold alloy contact is used as it has low ohmic and thermal resistance. They provide a lowcost and no frill method for voltage regulation. Diodeapplications semiconductor diode applications load. 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. Zener diodes when we first talked about practical diodes, it was mentioned that a parameter associated with the diode in the reverse bias region was the breakdown voltage, v br, also known as the peakinverse voltage piv. The zener diode mainly operates in reverse biased condition.
A diode, in electronics, is a two terminal electronic component with an asymmetric transfer characteristics, with low resistance to current flow in one direction and high resistance to current flow in the other direction. Zener diode characteristics zener regulator prelab. From the iv characteristics curve above, we can see that the zener diode has a. As with the rest of this series of videos, even though it references a particular course, it is still useful as a demonstration video. We operate a zener diode in reverse biased conditions, and this diode does not get damaged even when the voltage across this exceeds the reverse breakdown voltage. Feb 03, 2014 this diode model most accurately represents the true operating characteristics of the real diode. Silicon is preferred to diode because of its higher temperature and current capability. You are tasked to determine experimentally the characteristic curve of a reversebiased zener diode. The 1n4744 is a zener diode and has the lowest breakdown voltage.
Effect of swift heavy ion irradiation on the electrical. I am interested to measure the currentvoltage characteristics of a. Zener diode working, characteristics and application as. This is because it is usually not possible to break open a circuit to insert the ammeter. In zener diode, electric current flows from both anode to cathode and cathode to anode. Additionally, the voltage drop across the diode remains constant over a wide range of voltages, a feature that makes zener diodes suitable for use in voltage regulation. Pdf diode characteristics approaching bulk limits in gaas. Zener diode reverse characteristics curve by anshu kapoor duration. This nonlinear characteristic illustrates that during the operation of the n junction, the resistance is not constant. Plot a graph with reverse voltage along x axis and reverse current along y axis. The slope of the pn junction diode in forwarding bias shows the resistance is very low. To study and measure the effects of forward and reverse bias on the zener diode current. Electronics tutorial about the zener diode and how the zener diode can be used.
The application of this diode is in its reverse biased condition. This is just a formal introduction to zener diode with the related definitions and the vi characteristics. The electric field may become large enough that covalent bonds are broken and electronhole pairs are created. To study and verify the functionalityof zener diode in forward bias and reverse bias and to plot voltampere characteristics of zener diode. Draw the reverse characteristics of zener diode and determine its break down voltage. Secondly, a 24v hot plugin was tested to show that without the tvs zener diode, the voltage spike can exceed the bq243xx absolute maximum voltage of 30 v. Here you will learn, how the zener diode is used in reverse biasing. Vi characteristics of pn junction diode in 3biasing modes. To study the characteristics of the reflex klystron tube and to determine its electronic tuning range.
Basic electronics notes on vi characteristics of zener. This does not involve indepth concepts except for the mechanisms of breakdown between the zener breakdown and the avalanche breakdown. The complete vi characteristics of zener diode is as shown in figure. These types of diodes are commonly known as zener diodes and are. In the reverse biased mode zener diode has large breakdown voltage and though the current increases the voltage remains constant. Observation of characteristics of a zener diode debangshu mukherjee bs. The other differences between the pnjunction and zener diode are shown in the comparison chart. Static resistance of a pn junction diode is the ratio of forward voltage to forward current. Also, we describe how the zener diode is used as a voltage regulator, a clipping circuit and as a voltage reference. Due to heavily doped, its depletion layer is very thin and is order of micrometer.136 294 1389 791 354 437 1536 1143 1042 1125 505 1419 1368 1213 579 114 804 1008 994 176 65 822 594 458 979 179 732 1324 38 1169 423 974 394 968 325 1266 392 1478 1129 120 386