Pn junctions worksheet discrete semiconductor devices and. Learning to mathematically analyze circuits requires much study and practice. In solving the problem we have to remember only one simple concept that if the voltage that is applied to the p type material of the pn junction diode is higher than that of the voltage that is applied to the n type material of the pn junction diode,than the diode is said to be in the forward bias and vice versa. The device was named after clarence zener, who discovered this electrical property. Most semiconductor devices contains one or more pn junctions. The ball undergoes projectile motion so we have the kinematic equations for the ball. Projectile motion in electric field university of rhode. If an external dc voltage is given to the circuit in which the semiconductor diode is a part of it, results in a qpoint or operating point on the pn junction diode characteristic curve that does not alter with time. When the ntype semiconductor and ptype semiconductor materials are first joined together a very large density gradient exists between both sides of the pn junction. With the diode check function a good diode will show approximately. The baseemitter junction is usually forward biased and the basecollector junction is reversed biased when the junction transistor is used in a circuit. At the top of its flight, the vertical speed of an object in projectile motion is zero. Nov 23, 2014 we had already analyzed the working the of the pn junction diode in the previous post.
Pn junction diode baising and its vi characteristics. With the diode check function a specific known voltage is applied from the meter across the diode. Stay tuned with byjus to learn more about diode, semiconductor devices and many more with interesting video lectures. A semiconductor pn junction diode is a two terminal electronic device that allows current in only one direction. The other differences between the pn junction and zener diode are explained below in the comparison chart. Due to this electric field, an electron on the pside of the junction moves to the nside of the junction. When a ptype ge crystal is grown over an ntype ge crystal or viceversa, the common surface of the two types, is called a junction. Explain the formation of potential barrier and depletion layer. The p positive side contains an excess of holes, while the n negative side contains an excess of electrons in the outer shells of the electrically neutral atoms there. The result is that some of the free electrons from the donor impurity atoms begi.
Once launched, the projectile follows a parabolic path. Understand the physics of a pnjunction and how a junction diode is created 2. Formation of pn junction in actual practice, a pn junction will. What are the depletion width in the nregion, the depletion width in the pregion, and the builtin potential at 300k. This experiment uses a glass or plastic tube to launch a ball horizontally. The name diode is derived from diode which means a device that has two electrodes.
A pn junction is a junction formed by joining ptype and ntype semiconductors together in very close contact. P n junction diode a pn junction is known as semiconductor diode. Temperature coefficient of silicon junction transition capacity the transition capacity of a pn junction is a useful nonlinear capacitor because it. Silicon a single silicon atom consists of fourteen negatively. Here, we see that the direction of drift current is opposite to that of the diffusion current. We can then fill in the junction region of the band diagram as. Understanding the pn junction university of new south wales. A pn junction is said to be formed only when a bonding force is created between the ptype and ntype semiconductor. A pn junction is a boundary or interface between two types of semiconductor materials, ptype and ntype, inside a single crystal of semiconductor. Semiconductor pn junction diodes physically, diodes are formed by the interface between two regions of oppositely doped semiconductor i. Formation of pn junction in actual practice, a pn junction will not be formed if a ptype.
Physics of semiconductor devices pn junction depletion. But before we can understand how the pn junction works, we must first consider current flow in the materials that make up the junction. Find the dynamic resistance at 105 o c when the diode is forward biased with 0. Gravity is used to get the ball rolling along a straight long. If the diode is forward biased, it allows the electric current flow. As shown in the figure, pn junction diode is a 2 terminal polarity sensitive device. On the other hand, if the diode is reverse biased, it blocks the. Pn junctions consist of two semiconductor regions of opposite type.
Reverse bias of pn junction when the voltage is applied this way round it tends to pull the free electrons and holes apart, and increases the height of the energy barrier between the two sides of the diode. Lecture 15 the pn junction diode i iv characteristics november 1, 2005 contents. This is the basic construction of the pn junction diode. It is one of the simplest semiconductor devices as. In our study of projectile motion, we assumed that airresistance effects are negli gibly small. The major difference between pn junction and the zener diode is that the pn junction diode allows current to pass only in the forward direction, whereas the zener diode allows the current to flow both in the forward and the reversed direction. Semiconductor physics semiconductors and diodessemiconductors. Physics of semiconductor devices pn junction depletion width problem a silicon pn diode has a doping of n d 81015 1 cm3 and n a 210 16 1 cm3. Objective questions on pn junction diode electrical. Where, i d current through the pn junction, in amps. This allows electrical current to pass through the junction only. Topic 1 projectile motion with air resistance wustl physics. Hu slide 42 nregion pregion a b c d depletion layer neutral pregion neutral nregion ef 4. Pn junction diode applications pn diode applications.
The diode is firmed by doping a semiconductor like silicon or germanium with trivalent impurity e. Chapter 4 pn junctions university of california, berkeley. A pn junction is the metallurgical boundary between the n and pregions of a semiconductor crystal. To work these problems, separate the big three equations into two sets as.
The diode uses the properties caused by the depletion area of the junction. Download download projectile motion problems and solutions pdf read online read online projectile motion problems and solutions pdf let g be the gravitational constant. Pn junctions worksheet discrete semiconductor devices. Jan 29, 2019 pn junction diode is one of the fundamental elements in electronics. As a result it is almost impossible for any electrons or holes to cross the depletion zone and the diode current produced is virtually zero. The pn junction is the fundamental building block of the electronic age. The pn junction is a versatile element, which can be used as a. Due to this characteristic, the diode finds number of applications as given below. This page of application notes section covers pn junction diode applications. A pn junction diode is a twoterminal electronics element, which can be classified as either step graded or linear graded.
I s pn junction saturation current, in amps typically 1 picoamp. Pn junction tutorial introduction to pn junction diodes. Questions you should be able to answer by the end of todays lecture. Projectile motion in electric field electrostatic force. By exploring the electrical properties of silicon, it is possible to acquire an understanding of the inner workings of the pn junction. Definition, symbol, and types of diodes electrical4u. A zener diode is a type of diode that permits current not only 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.
For the love of physics walter lewin may 16, 2011 duration. When the potential formed by the widened depletion layer equals the applied voltage, the current will cease except for the small thermal current. Static resistance or dc resistance of a pn junction diode defines the diodes resistive nature when a dc source is connected to it. Understand the behaviour of a diode under forward and reverse bias and be able to plot the iv characteristic of an ideal diode 3. A pn junction is the simplest form of the semiconductor diode.
Projectile motion problems and solutions pdf telegraph. A pn junction diode is formed by doping one side of a piece of silicon with a ptype dopant boran and the other side with a ntype dopant phosphorus. There are two operating regions in pn junction diode. The pn junction diode the nature of the pn junction is that it will conduct current in the forward direction but not in the reverse direction. Semiconductor pnjunction diodes physically, diodes are formed by the interface between two regions of oppositely doped semiconductor i. Here we would like to analyse some more problems on this concept. The pn junction is of great importance as it is the main control element for the semiconductor devices. May 06, 2010 p n junction diode a pn junction is known as semiconductor diode. Solving problems on the concept of p n junction diode iit. Video lecture on what is projectile motion from motion chapter of applied physics for msbte semester 2. Image source forward biasing a pn junction diode is very simple. Jan 04, 2020 a pn junction is the simplest form of the semiconductor diode. What is a pn junction when a ptype semiconductor is suitably joined to an ntype semiconductor, the contact surface is called pn junction. The core point that we have to understand is when the voltage applied to the p type material is more than that of the n type than the diode is in the forward bias and it is able to pass the.
The simplest application of the pn junction is the bipolar junction diode often made from silicon or germanium. A pn junction diode is a basic semiconductor device that controls the flow of electric current in a circuit. The application of a reverse voltage to the pn junction will cause a transient current to flow as both electrons and holes are pulled away from the junction. A pn junction diode is formed when a ptype semiconductor is fused to an ntype semiconductor creating a potential barrier voltage across the diode junction 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.
The other differences between the pnjunction and zener diode are shown in the comparison. They are also called pn diodes in analogy with vacuum diodes. A bipolar junction diode is basically a pn junction with conducting terminals attached to each side of the junction. What happens when we join ptype and ntype semiconductors. The conversion of alternating current into direct current is known as rectification. 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. Solving problems on the concept of p n junction diode. A pn junction diode is made by forming a ptype region of material directly next to a ntype region. Difference between pn junction diode and zener diode. But in fact air resistance often called air drag, or simply drag has a.
The purpose of this project is to develop a functional pn semiconductor device simulator that is modular in nature in order to allow for flexibility during programming and to allow for future. May 16, 2015 for the love of physics walter lewin may 16, 2011 duration. It is therefore a basic tool for rectification in the building of dc power supplies. Boron or aluminium from one end to form ptype region and with pentavalent impurity like. Chapter 4 pn junctions a pn junction is present in every semiconductor device.
At the maximum height, the vertical speed will be zero otherwise the projectile would go higher. The 5 volume series by pierret and neudeck and jaeger, provide a strong basic on semiconductor physics. 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. Difference between pn junction diode and zener diode definition of pn junction diode and zener diode diode is an electronic component that allows the flow of electricity in one direction without resistance or with very little resistance while in the opposite direction has an infinite or at least very high resistance. It has a positive p side and a negative n side created by adding impurities to. Jan 21, 2019 what is a pn junction when a ptype semiconductor is suitably joined to an ntype semiconductor, the contact surface is called pn junction. The diode conducts when forward bias is applied and it will introduce zero resistance in the circuit. Projectile motion on an incline kinematics fundamentals. We have so far studied the projectile motion, using technique of component motions in two mutually perpendicular directions one which is horizontal and the. In ideal conditions, this pn junction behaves as a short circuit when it is forward biased, and as an open circuit when it is in the reverse biased. In forward bias condition, current is constant until certain voltage is reached. Pn junction diode and characteristics of pn junction diode.
Now that you are familiar with p and ntype materials, how these materials are joined together to form a diode, and the function of the diode, let us continue our discussion with the operation of the pn junction. A pn junction diode is twoterminal or twoelectrode semiconductor device, which allows the electric current in only one direction while blocks the electric current in opposite or reverse direction. Definition ptype semiconductor is suitably joined to ntype semiconductor,to conduct surface is called pn junction. P type and n type semiconductors, takenseparately are of very limited use. You just need to take a battery whose values can be varied from o to v volts, connect its positive terminal to the pside of pn junction diode and then connect the negative terminal of battery to the nside of the pn junction diode. Pn junction diode is one of the fundamental elements in electronics. In this type of diode, we dope one side of a semiconductor piece with an acceptor impurity and another side with a donor impurity. Likewise, different voltage v 2 across this same diode a diode of course results in a different current i 2.
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. An ideal germanium diode at room temperature has a static resistance of 4. An ideal silicon pn junction has a reverse saturation current of 0. Experimental methods py2108 2 1 learning objectives the objectives of this practical section are to 1. Projectile motion is the motion of an object that is moving in air and experiences the force of gravity.
From the above, it follows that zero power dissipation occurs in an ideal diode. A pn junction diode allows electric current when it is forward biased and. Likewise, we can find the voltage across the diode. This pn diode applications are very useful for beginners. Volume ii 2nd edition modular series on solid state dev. The term junction refers to the boundary interface where the two regions of the semiconductor meet.
N nonideality coefficient, or emission coefficient typically between 1 and 2. Testing a diode is quite simple, particularly if the multimeter used has a diode check function. A pn junction diode is a twoterminal electronics element, which can be classified as either. Typically, students practice by working through lots of sample problems and checking their answers against those provided by the textbook or the instructor. Diode characteristics dynamic resistance, transition time.
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