Piv is the peakinversevoltage of the diode forward bias occurs when the ptype block is connected to the positive terminal of the battery and the ntype is connected to the negative terminal of the battery, as shown below. A diode is used to block the electric current flow in one direction, i. Zener diode made specially to operate in the reverse breakdown region. Electronics and communications video lectures from nptel, iit. Lightemitting diodes leds in a diode formed from a direct bandgap semiconductor, such as gallium. Electrical engineering introduction to electronic circuits nptel. 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. Am circuit detector diodes and diode circuits video lecture. The zener diode working principles and its various.
Uses of zener diode and its practical application in real life. They are also called pn diodes in analogy with vacuum diodes. Zener diode is on when it operates on the zener region, i. Gate 2011 electronics and communication engineering set c. Effectively this diode sees negative to a more positive.
In other words, if the voltage applied on the real diode reaches 0. Basic zener regulator analysis procedure step 1 determine the state of the zener diode by removing it from the network and calculating the voltage across the resulting open circuit. To study and measure the effects of forward and reverse bias on the zener diode current. Your browser does not currently recognize any of the video formats available. The main characteristic of a pnjunction or a diode is that for positive voltages forward bias the diode is conduction, whereas for negative voltages reverse bias the current flow is blocked. They are well suited for applications such as cellular phones.
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. The pn junction is a versatile element, which can be used as a. Also, it explains the phenomenon of shockleyqueisser limit. Such a high potential graidient,backbiasing the diode cause a flow of minority carrier across the junction. Solve each circuit with its corresponding diode equation. The zener diode is a type of diode which operates under the reverse bias that breakdowns when the applied voltage reaches a particular reverse bias voltage or knee voltage. Department of eecs university of california, berkeley eecs 105 spring 2004, lecture 10 prof. Diodes which are designed with adequate power dissipation capabilities to operate. Advanced electric drives nptel online videos, courses iit. Nptel video lectures, iit video lectures online, nptel youtube lectures, free video lectures, nptel online courses, youtube iit videos nptel courses.
As the voltage rises into e reverse direction, initially very little current flows. To construct a zener voltage regulator and experimentally determine the range over which the zener maintains a constant output voltage. A point contact diode with glass encapsulation and a schottky diode. Nptel video lectures, iit video lectures online, nptel youtube lectures, free video lectures, nptel online. The zener diode operates just like the normal diode when in the forwardbias mode, and has a turnon voltage of between 0.
A will be outside the unit circle so that integration value is zero. Due to this properties a diode can be used for several applications like rectifiers, sampling circuits, demodulators, logic gates and so on. Biasing the field effect transistor transductance curves. Such junctions show a pronounced rectifying behavior. Both types are used with the zener effect predominating under 5. In impatt diode extremely high voltage gradient is applied400kvcmwhich a normal which a normal pn junction cant withstand.
Circuit symbol for the device is also shown with the inward arrow depicting the ptype material side. Pn junction diode conceptual lecture gate ece video youtube. Yellow and green indicator leds, an infra red photodiode. Introduction to basic electronics, electronic devices, semi conductor diodes, wave shaping using diodes, zener diode characteristics, transistor biasing, hparameters, frequency analysis, differential amplifiers, types of feed back, characteristics of operation amplifier, oscillatiors, unit junction transistor ujt. The baritt diode or barrier injection transit time diode, bears many similarities to the more widely used impatt diode. Zener diodes diodes that can be made to conduct backwards. Find materials for this course in the pages linked along the left.
This effect, called zener breakdown, occurs at a precisely defined voltage, allowing the diode to be used as a precision voltage reference. Distributed generation technologies, distributed storage technologies, distribution system protection, circuit breaker coordination, symmetrical component analysis and sequence excitation, modeling of distribution system components, protection components, impact of. The value of the integral where is the circle is given by a 0 b 110 c 45 d 1 ans. Parametric solution of diode circuits is desirable. In the circuit above, there is 10 v across the zener diode, and 2 v across the resistor. However, once it reaches that voltage, real diode starts allowing the electric current. It is also called as esaki diode named after leo esaki, who in 1973 received the nobel prize in physics for discovering the electron tunneling effect used in these diodes. Semiconductor diodes semiconductor materials intrinsic and extrinsic types ideal diode terminal characteristics of diodes.
Zener diode voltage regulators s bharadwaj reddy june 3, 2017 december 12, 2018 zener diodes can be used to produce a stabilised voltage output with low ripple under varying load current conditions. Diodes in the first lecture, we discussed linear circuit components resistors, capacitors, and inductors we found that we could build some electronic circuits using only these devices however, much of electronics in particular digital electronics depends upon nonlinear devices. Distributed generation technologies, distributed storage technologies, distribution system protection, circuit breaker coordination, symmetrical component analysis and sequence excitation, modeling of distribution system components, protection components, impact of distributed generation of distribution. Power supplies applications diodes and diode circuits. Chitralekha mahanta, department of electronics and communication engineering,iit guwahati. Gate 2011 electronics and communication engineering set c q. This principle of diode makes it work as a rectifier. A simple zener diode voltage regulator in the voltage regulator the zener diode operates in the breakdown region, which ensures approximately constant voltage across it. Chitralekha mahanta, department of electronics and communication engineering,iit. From the above, it follows that zero power dissipation occurs in an ideal diode.
Doped semiconductors ntype materials ptype materials diodes and transistors. Working of the zener diode is similar to a pn junction diode in forwarding biased condition, but the uniqueness lies in the fact that it can also conduct when it is connected in reverse bias above its thresholdbreakdown voltage. Zener diodes are normal pn junction diodes operating in a reversebiased condition. There are many circuits that use zener diodes, ranging from very simple zener diode circuits, up to far more complicated ones. Multiple diode analysis consider the 2 diode circuit below. If you have watched this lecture and know what it is about, particularly what engineering topics are discussed, please help us by commenting on this video with your suggested description and title.
Basic diode electronics introduction to diodes the pn junction the pn junction is a homojunction between a ptype and an ntype semiconductor. Lecture series on electronics for analog signal processing i by prof. It allows the current to flow as like a normal pn junction diode when it is forward biased and block the reverse flow of current during the reverse bias up to the breakdown voltage. When the input voltage increases and reaches the zener breakdown voltage, the current through the diode will create a voltage drop across the resistor. Zener diode examples and circuit analysis book pdf by.
This lecture uncovers the basic science of semiconductor devices and solar cells, including pn junction and photovoltaic effects. Here with the applied voltage, the voltage across the zener. Make a guess as to one of the possible states of the circuit. On on on off off on off off d1 d2 possible states for the 2 diodes. Jul 24, 20 for the love of physics walter lewin may 16, 2011 duration. Microsemi offers low voltage avalanche zener diodes in the do2aa, do35, do41 and do7 packages. Zener voltage v z is the reverse voltage at which breakdown occurs in a zener diode search logic. Zener diode operates in reverse bias rb at the zener voltage v z. They can also be used in other circuits apart from just providing a voltage reference. Lecture 10 zener regulator and voltage regulator youtube.
Products returned as matches will meet all specified criteria. Lets look at the path, it would go negative to the ground and then it would go to the positive terminal. For a circuit to allow the current flow in one direction but to stop in the other direction, the rectifier diode is the best choice. Practice problems by patrick hoppe these deal with the determination of series current, zener current, and load current, and if the zener diode is. A zener diode is a type of diode that allows current to flow in the conventional manner from its anode to its cathode i. Many diodes described as zener diodes rely instead on avalanche breakdown. If a diode is assumed on, verify the current calculated flows in the correct direction consistent with. Basic coursessem 1 and 2 basic electronics and lab nptel. The fixed voltage property of zener diodes makes them extremely handy as quick voltage references.
Semiconductors, diodes, transistors horst wahl, quarknet presentation, june 2001 electrical conductivity. Diodes and diode circuits tlt8016 basic analog circuits 20052006 11 3. Basics currentvoltage characteristic of a zener diode with a breakdown voltage of 17 volt. Zener diodes or voltage reference diodes are used in a variety of circuits to enable them to provide a voltage reference. Zener diode circuit analysis consider the circuit below. Note that the load resistor r l is in parallel with the zener diode, so that the voltage v o across this load resistor is equal to the zener diode voltage v z. Dec 08, 2012 the power diode plays the vital role in the power electronics circuits. These devices are designed to provide voltage regulation with minimum space requirement. P517617 lec5, p1 diodes and transistors diodes what do we use diodes for.
A zener diode is one in which the reverse breakdown occurs due to electron quantum tunneling under high electric field strength called zener effect. The diode is firmed by doping a semiconductor like silicon or germanium with trivalent impurity e. Natarajan, does not currently have a detailed description and video lecture title. This series of zener diodes is offered in the convenient, surface mount plastic sot23 package. The zener diode has a normal forward characteristic where the current rises after the initial turnon voltage is reached. Pn junctions consist of two semiconductor regions of opposite type. The convention for the direction of the diode current and voltage are also shown. A diodes iv characteristic is shown in figure 6 below.
We call this particular regulator circuit the shunt regulator. This video lecture, part of the series basic electronics by prof. Use the inequality for that diode state range of validity to find the range of circuit variable which leads to that state. A pn junction is the metallurgical boundary between the n and pregions of a semiconductor crystal. Boron or aluminium from one end to form ptype region and with pentavalent impurity like phosphorous from the other end to form ntype region on the other end. This is an example of a primary application of zener diodes voltage regulation. Zener diodes with glass or black resin encapsulation. Zener diodes unlike normal diodes, zeners are designed to operate in the breakdown region from the previous page, we see that the current vs. Zener diode is reverse biased during its operation. Aug 31, 2008 lecture series on electronics for analog signal processing i by prof. First of all, we come in with our, lets see i dont know if you can see, okay now you can see that, we come in without am modulated signal, the first thing that it hits is this diode. 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. The transductance curve of a jfet is a graph of output current i d vs input voltage v gs as shown in fig. Radhakrishna rao, department of electrical engineering,iit madras.
With 2 v across a 400 ohm resistor, the current through that resistor and the diode, in series is 5 ma. Diode circuits tutorial pdf 25p this note covers the following topics. It acts as a diode, which can serve in electronics as a rectifier, logic gate, voltage regulator zener diode. This causes a excess drift current, and can be amplified to act as a receiver for optical signals from an optical fiber. The simplest semiconductor device is a pnjunction diode. Lecture 101 high power diode lasers computer engineering. In the circuit shown below, the zener diode is ideal and zener voltage is 6 v. Tunnel diode is a highly doped semiconductor device and is used mainly for low voltage high frequency switching applications.
The major and most important applications of power diode in converter circuits are working as a rectifier remember that the rectification operation is uncontrollable, freewheeling diode or flyback diode, reverse voltage protection, voltage regulation circuits etc. Notice this diode, if we start from there the current flows from negative to more positive. Tunnel diode working principle and characteristics ece. Nptel provides elearning through online web and video courses various streams. This means the diode has not started conducting current through it. Like the more familiar impatt diode, the baritt is used in microwave signal generation, often in applications including burglar alarms and the like, where it can easily produce a simple microwave signal with a relatively low noise level. Zener diode working with circuit diagram and applications.
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