When you take a block of silicon and dope part of it with a trivalent impurity and the other part with a pentavalent impurity, a boundary called the pn junction is formed between the resulting ptype and ntype portions. Develop an understanding of the pn junction diode and its behavior. Zener diode circuit analysis consider the circuit below. Nptel video lectures, iit video lectures online, nptel youtube lectures. These devices may not be a simple pn type diode, but behave electrically identical to a pn junction diode. Lecture series on digital integrated circuits by dr.
Metallurgy and material science electronic materials. Diode operation diode is made from a small piece of semiconductor material, usually silicon, in which half is doped as a p region and half is doped as an n region with a pn junction and depletion region in between. Typically, students practice by working through lots of sample problems and checking their answers against those provided by the textbook or the instructor. So, you want to download all of the video lectures for a course in nptel. If we join a piece of p type material to a pieceof n type material such that the crystalstructure remains continuous at the boundary, a pn junction is formed 2. A k schematic symbol for a pn junction diode p n representative structure for a pn junction diode.
Here you may find a good video with animation, which explains the formation of pn junction. This creates barrier that reqqpp yuires approximately. Lecture 15 the pn junction diode i iv characteristics april 3, 2003 contents. 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. These diodes have a very accurate and specific reverse. Amitava dasgupta, department of electrical engineering,iit madras. A k schematic symbol for a pn junction diode p n representative structure for a pn junction diode zener diodes. Zero current flows in a reversebiased ideal diode i. I have developed a second chapter on the series, which explains the characteristics of pn junction diode.
Diode construction techniques the pn junction of a diode may be one of three types. When pn junction is forward biased, then also a capacitance is defined called diffusion capacitance. The n region has many free electrons majority carriers and only a. Choose a silicon diode and measure its forw ard and reverse resistance with. I d i sevdvt 1 as described in the last slide, i d is the current through the diode, i s is the saturation current and v d is the applied biasing voltage. This causes electrons from nregion to get attracted to positive terminal of the battery and holes by the negative terminal. A pn junction diode is one of the simplest semiconductor devices around, and which has the characteristic of passing current in only one direction only. Jul 06, 2016 when you take a block of silicon and dope part of it with a trivalent impurity and the other part with a pentavalent impurity, a boundary called the pn junction is formed between the resulting ptype and ntype portions. Jul 21, 2008 lecture series on digital integrated circuits by dr. A pn junction is a junction formed by joining ptype and ntype semiconductors together in very close contact. How to download all of the lectures for a course in nptel quora. How a pn junction formed in a diode engineering tutorial. The two basic processes which cause electrons and holes to move in a semiconductor are. Octavian florescu 2 the pn junction diode schematic diagram ptype ntype id.
The diode diode structure and symbol the diode is a single pn junction device with conductive contacts and wire leads the p region is called anode and the n region is called cathode the arrow points in the direction of conventional current opposite to electron flow typical diodes forward and reverse bias of a diode the ideal diode model. How to download all of the lectures in pdf for a course in. Similarly, a diode presents a small resistance in the forward direction and a large resistance in the reverse direction. Learning to mathematically analyze circuits requires much study and practice. Electrical engineering digital integrated circuits nptel. Consider an ideal pn junction diode with crosssection dimension of 10. You will find all pdf s and also as mp3 file for all video lectures which are in nptel.
Semiconductors, diodes, transistors horst wahl, quarknet presentation, june 2001 electrical conductivity. Electrical energy conversion by converters, the lost history of the transistor, future electronic power distribution systems, basic strategies in power electronics, power devices, mechanical design and cooling techniques, dcdc converters, linecommutated topologies, voltage source inverters, active compensation. Where, i d current through the pn junction, in amps. Pn junction diode pn junction diode the pn junction. It will help you to grasp concepts behind pn junction even better. Are specifically designed to operate under reverse breakdown conditions.
Are used to allow current to flow in one direction while blocking current flow in the opposite direction. Relationship between diode current and diode voltage. Diodes in the first lecture, we discussed linear circuit components resistors, capacitors, and inductors. Chitralekha mahanta, department of electronics and communication engineering,iit guwahati.
N nonideality coefficient, or emission coefficient typically between 1 and 2. Iv characteristics pn junction diode reverse biasing a pn junction when the polarity of the battery is reversed, the cathode is connected to positive end of the battery and anode to negative. Electrical circuit with pn diodes typical led bias circuit forward bias applied e rb 0 0. These kinds of transformer are termed as the real transformers. Pn junction tutorial introduction to pn junction diodes. Id decreases in equilibrium, there is a v r across the terminals greater than v 0 if i is, the diode breaks down. Part 5 large signal complete model and small signal limited use models of a diode reading. When the diode is forwardbiased, it can be used in led lighting applications. Aug 27, 2018 so, you want to download all of the video lectures for a course in nptel. Nov 15, 2017 you will find all pdf s and also as mp3 file for all video lectures which are in nptel. If the reverse voltage exceeds the breakdown voltage, the zener diode will. The behavior of the pn junction with regards to the potential barriers width produces an asymmetrical conducting two terminal device, better known as the pn junction diode. P type and n type semiconductors, takenseparately are of very limited use.
But not exactly even if the external voltage or bias is applied in the proper direction, no current flows until the depleted region becomes thin enough voltage needed to do this is called the diode drop if enough voltage is applied in the reverse bias direction. Lecture 15 the pn junction diode i mit opencourseware. They are also called pn diodes in analogy with vacuum diodes. You can find them according to your branch and subject in the below link national mission on education through ict this was initiated by iit madras.
The pn junction diode is the typical diode that has been used in the previous circuits. The diode is firmed by doping a semiconductor like silicon or germanium with trivalent impurity e. Circuit symbol for the device is also shown with the \inward arrow depicting the ptype material side. University of gene va lab ii diodes tpaelectronique 1 diode characteristics. Fall 2017, electronic circuits i this energy loss results in a voltage drop across the pn junction equal to the barrier potential 0.
An ideal diode is a perfect conductor in one direction, and a perfect resistor in the other. Outline drift current diffusion current pn junction. Pn junction diode pn junction diode the pn junction diode. Determine the polarity of the voltage across the diode, then replace the diode with.
However, if we were to make electrical connections at the ends of both the ntype and the ptype materials and then connect them to a battery source, an additional energy. Pn junctions consist of two semiconductor regions of opposite type. Here discussion is limited only to acquaintation with the basic techniques and terminology not expertise in fabrication. Our pn junction behaves kind of like an ideal diode. The pn junction current is much higher than sd diode current due to. Use the diode equation for that state to solve the circuit equations and find i d and v d 3. How to download all of the lectures for a course in nptel. Recipe for solving diode circuits state of diode is unknown before solving the circuit 1. In a grown junction method the earliest technique used, intrinsic semiconductor material and ptype impurities are placed in a quartz container and heated until. In practice, the pn junction is formed from a single mono crystalline structure by adding carefully controlled amounts of donor and acceptor impurities. Lecture 16 the pn junction diode ii equivalent circuit model november 3, 2005 contents. Chitralekha mahanta nptel online videos, courses iit video lectures. Depletion region has greater width in n region for gaas diode while depletion. Majority carriers that are injected to the oppposite side of the diode under forward bias become minority carriers and recombine.
Pn diode equilibrium voltage zso in thermal equilibrium, at room temperature, a silicon pn diode will have a potential difference between the p and n sides of. Pn junctions worksheet discrete semiconductor devices. A pn junction is the metallurgical boundary between the n and pregions of a semiconductor crystal. I s pn junction saturation current, in amps typically 1 picoamp. Parasuraman,department of metallurgy and material science,iit madras.
Doped semiconductors ntype materials ptype materials diodes and transistors. Lecture 16 the pn junction diode ii mit opencourseware. In most of the transformer, there are losses due to various reasons and doesnt have the efficiency of the ideal transformer. In equilibrium, the total current balances due to the sum of the individual components. Lecture 15 the pn junction diode i iv characteristics november 1, 2005 contents. Nptel provides elearning through online web and video courses various streams. A semiconductor pn junction diode is a two terminal electronic device that allows current in only one direction.
General introduction to fabrication techniques of a pn junction diode. Electronic materials, devices, and fabrication by prof s. Such junctions show a pronounced rectifying behavior. Schottky barrier diode the schottky diode named after german physicist walter h. Pn junctions worksheet discrete semiconductor devices and. So, in this pn junction tutorial, we will discuss some of the basics of a pn junction, how a pn junction is formed, characteristics of pn junction and many other aspects. Write down all circuit equations and simplify as much as possible 2. Video created by georgia institute of technology for the course introduction to electronics. A ptype material consists of silicon atoms and trivalent impurity atoms such as. Circuit symbol for the device is also shown with the. Unit 6 applications of pn junctions and details of metal. Calculate the builtin potential for a silicon pn junction with nd1016.
The pn junction is the basis for diodes, certain transistors, solar cells, and other devices. The term refers to a region near the pn junction where the electron and hole concentrations are much. Pdf fabrication of pn junction diode using snosno2. Example zener diode circuit analysis blank ku ittc.
P and n type materials are joined together to form a pnp and n type materials are joined together to form a pn junction a diode is nothing more than a pn junctiona diode is nothing more than a pn junction. Explain the formation of potential barrier and depletion layer. Zero voltage drop occurs across a forwardbiased ideal diode i. For an unbiased pn junction diode at thermal equilibrium, which of the. The current through an ideal pn diode at is when a. Telecharger des cours et exercices corriges delectronique en pdf,formation pour tout les niveaux dans les divers themes. The term junction refers to the boundary interface where the two regions of the semiconductor meet. Although it is not discussed majorly outside the concept of pn junction diode and sometimes the transistor, a pn junction is an essential topic in semiconductor electronics. The pn junction is a versatile element, which can be used as a. Pn junction diode the pn junction diode the effect described in the previous tutorial is achieved without any external voltage being applied to the actual pn junction resulting in the junction being in a state of equilibrium. Oct 07, 2008 lecture series on basic electronics by dr. Fabrication of pn junction diode using snosno2 thin films and its device characteristics article pdf available in electronic materials letters 104. Lecture pn junction and diodes ii, diode applications i.
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