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. Feb 09, 2015 construction of zener zener diodes are designed to operate in reverse breakdown. The avalanche break down occurs in both rectifier and zener diodes at a sufficiently high reverse voltage. Diodes have two active electrodes between which the signal of interest may flow, and most are used for their unidirectional electric current property. Dec 11, 2017 diode seminar ppt and pdf report download. Recipe for solving diode circuits state of diode is unknown before solving the circuit 1. Zener diode voltageregulator circuits 22 what is a zener diode. Normal diodes will also break down with a reverse voltage but the voltage and sharpness of the knee are not as well defined as for a zener diode. When the doping is heavy, even the reverse voltage is low, the electric field at barrier will be so strong thus the electrons in the covalent bonds can break. Zener diodes are like ordinary pn junction diode except that it is properly doped so as to have a sharp breakdown voltage. When the voltage across the terminals is reversed and the potential reaches the zener voltage or knee, the junction will break down and current will flow in the reverse direction a desired characteristic.
Diodes and diode applications topics covered in this ppt semiconductor materials the pn junction diode voltampere characteristic curve diode app. Zener diode forward bias when a zener diode is forward biased, it operates as a normal diode. Types of diodes small signal, led, schottky, zener. When connected in parallel with a variable voltage source so that it is reverse biased, a zener diode conducts when the voltage reaches the diode s reverse breakdown voltage. Find powerpoint presentations and slides using the power of, find free presentations research about zener presentation ppt. Zener diode in may applications, operation in the reverse breakdown region is highly desirable. If a p and n region are heavily doped then the breakdown voltage can be reduced. These include small signal diodes, zener diodes, light emitting diodes, schottky diodes, tunnel diodes, avalanche diodes, etc. Zener diodes can be used to produce a stabilised voltage output with low ripple under varying load current conditions. Ppt zener diodes electrical engineering ee notes edurev. Notice the change of voltage scale between the forward biased positive. Such junctions show a pronounced rectifying behavior.
The breakdown voltage of a zener diode is carefully set by controlling the doping level during manufacture. Diode a diode is a specialized electronic component with two electrode called the anode and the cathode. Lets try again, this time with our friend, the zener diode. Essentially, it allows an electric current to flow in one. The zener diode working principles and its various. Zener diodes diodes that can be made to conduct backwards. Finally, lets try using one fat 20 v zener diode type 1n5357brlg, to drop some of the load. The pn junction is a versatile element, which can be used as a. A zener diode is like a normal silicon diode, where a forward biased diode will pass current with a 1 volt drop.
Stimulated emission is the basis of working of a laser diode. Zener diode properties the zener diode is a unique device which exploits a property of diodes that is generally avoided in standard diode applications. Workable on 230 volts, ac fitted with zener diode 8. Dec 19, 2017 apr 11, 2020 ppt zener diodes electrical engineering ee notes edurev is made by best teachers of electrical engineering ee. A zener diode is a type of diode that allows current to flow in the conventional manner from its anode to its cathode i. Zener diode definition a zener diode is a type of diode that permits current to flow in the forward direction like a normal diode, but also in the reverse direction if the voltage is larger than the breakdown voltage known as zener knee. By passing a small current through the diode from a voltage source, via a suitable current limiting resistor r s, the zener diode will conduct sufficient current to maintain a voltage drop of vout.
Zener diode symbol zener diode circuit zener diode vi characteristics zener diode working zener diode applications faqs. Basic diode electronics introduction to diodes the pn junction the pn junction is a homojunction between a ptype and an ntype semiconductor. Two types of reverse breakdown in a zener diode are avalanche and zener. Outlines introduction of zener diode construction of zener diode working of zener diode application of zener diode numerical of zener diode 3. A specific diodes vf depends on what semiconductor material its made out of. A 10 v zener diode type 1n4740 is placed in series with a resistor and a fixed 12 v power supply. Pn junctions consist of two semiconductor regions of opposite type. A pn junction is the metallurgical boundary between the n and pregions of a semiconductor crystal. Apr 11, 2020 ppt zener diodes electrical engineering ee notes edurev is made by best teachers of electrical engineering ee. In this tutorial, we will learn about different types of diodes. Zener diode definition a zener diode is a type of diode that permits current to flow in the forward direction like a normal diode, but also in the reverse direction if the voltage is larger than the breakdown voltage known as zener knee voltage or zener voltage. Zener diode free download as powerpoint presentation.
Zener diode characteristic apparatus electronics equipmentzener diode characteristic apparatus with build in stabilized power supply. In other words, the zener diode operated in this region will have a relatively constant voltage across it, regardless of the value of current through the device. Features, specifications, alternative product, product training modules, and datasheets are all available. This voltage is generally avoided in standard diodes, but. Zener diode definition, vi characteristics, and breakdown. Zener diode vi characteristics reverse characteristics of zener diode ideal zener diode equivalent circuit model practical zener diode equivalent circuit model in rbr. Ppt zener diode applications powerpoint presentation. Zener diode voltages as well as producing a single stabilised voltage output, zener diodes can also be connected together in series along with normal silicon signal diodes to produce a variety of different reference voltage output values the values of the individual zener diodes can be chosen to suit the application while the silicon. A lightemitting diode led is a diode that emits a certain color light when forwardbiased. This document is highly rated by electrical engineering ee students and has been viewed 457 times. This effect, called zener breakdown, occurs at a precisely defined voltage, allowing the diode to be used as a precision voltage reference. Zener diode applications chapter 3 overview zener diodes zener characteristics zener diodes diode types rectifier zener lower vz due to more heavily. The breakdown voltage of zener diodes will be constant for a wide range. Ppt zener diode powerpoint presentation, free download id.
Zener diode voltage regulators 6 for step 3 we calculate the maximum power dissipation of the zener diode. Ppt zener diode applications powerpoint presentation free to download id. Zener diode charceteristics voltage after breakdown is also called zener. Diodes exclusively block current in the reverse direction whereas the reverse voltage is within a restricted vary and if not reverse barrier breaks and conjointly the. Zener diodes as voltage regulators a circuit diagram symbol for a zener diode.
An ordinary diode operated in this region will usually be destroyed due to excessive current. This property allows the use of the zener diode as a simple. Introduction the zener diode is a silicon pn junction devices that differs from rectifier diodes because it is designed for operation in the reversebreakdown region. Diodes have two active electrodes between which the signal of interest may flow, and most are used for. Ppt diodes powerpoint presentation free to download id. The resistance depends on the amount of current i d in the diode.
Ppt zener diode applications powerpoint presentation free. They are also called pn diodes in analogy with vacuum diodes. Basics currentvoltage characteristic of a zener diode with a breakdown voltage of 17 volt. A zener diode is a special diode that has been optimized for operation in the breakdown region. Diodes and diode applications electronics ppt web4study. The adobe flash plugin is needed to view this content. In this case the electrons and holes are swept across the junction an large current flow through it. This was a bad thing before the whole avalanche breakdown, large current. Browse digikeys inventory of power zener diodeszener single.
The basic purpose of a power supply is to provide one or more fixed voltages to the working circuit, with sufficient current handling capacity to maintain the operating conditions of the circuit. A diode can be defined as the fundamental electronic component that allows the flow of electricity in one direction only. Then, the output on the anode of the zener is just 16 v, well within the safe input range of the regulator. Diodes and transistors university of california, berkeley. The voltage across the diode is fairly constant 26mv for 25 c. Zener diode breakdown diode ppt video online download. Use the diode equation for that state to solve the circuit equations and find i d and v d 3. Zener diodes are widely used as voltage references and as shunt regulators to regulate the voltage across small circuits. Zener breakdown occurs in a zener diode at low reverse voltages. In electronics, a diode is a twoterminal device thermionic diodes may also have one or two ancillary terminals for a heater. It is acting as normal diode while forward biasing.
Ppt diodes powerpoint presentation free to download. A semiconductor device that generates coherent light of high intensity is known as laser diode. A zener diode is heavily doped to reduce the reverse breakdown voltage. Laser is an abbreviation for light amplification by stimulated emission of radiation. A free powerpoint ppt presentation displayed as a flash slide show on id. A specific diode s vf depends on what semiconductor material its made out of.
A zener diode is like a normal silicon diode, where a forward biased diode will pass current with a. Ppt zener diode applications powerpoint presentation, free. Diode circuits operating in the reverse breakdown region. Powerpoint slide on light emitting diode leds compiled by c.
Zener diode applications powerpoint ppt presentation. It acts as a diode, which can serve in electronics as a rectifier, logic gate, voltage regulator zener diode. A zener diode is a pn junction semiconductor device designed to operate in the reverse breakdown region. Zener diodes are designed to operate in the reverse breakdown region.
The zener diode exhibits a constant voltage drop when sufficiently reversedbiased. Zener diode, resistors, power supply, multi meter circuit diagram. The color of light emitted by an led is determined by the type of material used in doping. Use the diode equation for that state to solve the circuit equations and find i. The worst case situation occurs when vin is at the maximum value and the load current is at the minimum value as that results in the highest current through the zener diode. Currentvoltage characteristic of a zener diode with a breakdown voltage of 17 volt. This effect, called zener breakdown, occurs at a precisely defined voltage, allowing the diode to be used as a precision voltage. Ppt zener diode powerpoint presentation free to download id.
Zener diode is used as shunt voltage regulator for regulating voltage across small loads. In the forward bias direction, the zener diode behaves like an ordinary silicon diode. The zener diode working principles and its various applications. Power above 500 mw, zener diodes, diodes and rectifiers manufactured by vishay, a global leader for semiconductors and passive electronic components. The resistor value is chosen such that several ma flow through it and through the zener, keeping it in its breakdown region. A zener diode is a diode that breaks down at a specific voltage when it is reverse biased. They are designed to breakdown in a reliable and nondestructive way so that. Power is calculated by multiplying current by voltage pie, so we can calculate power dissipations for both the resistor and the zener diode quite easily. The reverse breakdown voltage is relatively insensitive to the current flowing thought the diode the reverse current. View and download powerpoint presentations on zener diode as voltage regulator ppt. For each approved ppt you will get 25 credit points and 25 activity score which will increase your profile visibility.
Zener diode and regulators zener diodes are used to maintain a fixed voltage. Typical diodes have a very high reverse breakdown voltage, the voltage at which the diode begins to conduct in the reverse direction. A diode is also a tool that exclusively permits unidirectional flow of current if the diode is operated at a particular voltage level. Most diodes are made with semiconductor materials such as silicon, germa. 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. Power supply, output and meters connections are brought out on the panel. Zener diodes are normal pn junction diodes operating in a reverse biased condition.
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