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# Switching characteristics of PN junction diode ppt

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1. Pn junction diode 1. P type and N type semiconductors, takenseparately are of very limited use.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. It can function as
2. o Thus the P N junction diode allows the electrons flow only when P is positive , o This property is used for the conversion of AC into DC , Which is called rectification. 13 40 30 20 10 40 Forward Bias Region 140 V (volts) 120 80 0.4 2 6 0.8 12 V (volts) Reverse Bias Region Figure 5.1: Diode Characteristics
3. PN-junction diode: I-V characteristics Topics: PN Junction under bias (qualitative discussion) Ideal diode equation Deviations from the ideal diode | PowerPoint PPT presentation | free to view p-n junction theory - basics of p-n junction.doping ,semiconductors,impurities,silicon,germanium,biasing,conduction ctc | PowerPoint PPT presentation.

p-n junction diode characteristics theory:-a p-n junction diode conducts only in one direction. the v-i characteristics of the diode are curve between voltage across the diode and current through the diode. when external voltage is zero, circuit is open and the potential barrier does not allow the current to flow. therefore, the circuit current is zero. when p-type (anode is connected to +ve. Diode v i characteristic 1. Diode V-I Characteristic By Unsa Shakir 2. PN-Junction Diode Characteristics Forward Bias --- External battery makes the Anode more positive than the Cathode --- Current flows in the direction of the arrow in the symbol Describe the procedure for testing zener diodes Zener Diode Characteristics Zener diode Operates at voltages that exceed breakdown voltage Manufactured with a specific breakdown voltage (EZ) Packaged like PN junction diodes Power dissipation Based on temperature and lead lengths Zener Diode Characteristics (cont'd.) Figure 21-1

However the stage is set to see how the PN junction functions as a diode. 6. . At the p-n junction, electrons from the n-type semiconductor will be attracted to the holes in the p-type semiconductor. As a result, the holes and the electrons at the p-n junction disappear, forming a layer called depletion layer. At the same time, the p-type. 3. A diode in which the reverse current varies directly with the amount of light. Symbol 8. Explanation: 1. The photodiode has a small transparent window that allows light to strike the pn junction. 2. when its pn junction is exposed to light, the reverse current increases with the light intensity Diode is a two terminal PN junction that can be used in various applications. One of such applications is an electrical switch. The PN junction, when forward biased acts as close circuited and when reverse biased acts as open circuited. Hence the change of forward and reverse biased states makes the diode work as a switch, the forward being ON. diode switching timespn junction switching timesreverse recovery timeforward recovery timestorage timetransition timewhy reverse recovery time dominates over.. Diode: Application - Diode: Application Half-Wave Rectifier One of the most important uses of a diode is rectification. The normal PN junction diode is well-suited for this purpose as it | PowerPoint PPT presentation | free to view. Chapter 6-1. PN-junction diode: I-V characteristics - Chapter 6-1

### Switching diodes - Available at TTI - tti

1. Diffusion and drift can occur at the same time. A look at the short pn-diode PN diode Short PN diode Short PN diode Short PN diode Short PN diode Contents of course this year Long pn diode Introducing the concept of recombination of carriers. Switching of the pn diode, where does the delay come from
2. al pn junction device. When anode is positive with respect to the cathode, the diode is said to be forward biased and it. conducts
3. switching characteristics of diode When diode is switched from forward biased to the reverse biased state or viceversa, it takes finite time to attain a steady state. This time consists of a transient and an interval of time before the diode attains a steady state

• Circuit models of PN junction diodes • Small signal modeling of nonlinear circuit elements • Small signal models of PN junction diodes • Junction resistance and capacitances ECE 315 -Spring 2006 -Farhan Rana -Cornell University Current Flow in a PN Junction Diode I Area A p n d p p a n n n o i KT qV D T o L W N L D L W N L. In this article, we learn about PN junction diode characteristics in detail - like how to bias a PN junction (Forward & Reverse bias methods), behavior of PN junction during forward & reverse bias setups, how to plot the VI characteristics, what is reverse breakdown and many other essential concepts regarding a PN junction diode. So let's begin.. Fig1 Switching characteristics of diode. 2. Reverse recovery time: From the Fig1, reverse recovery time is addition of storage time and transition interval. When the diode is in forward bias and immediately switched to reverse condition, the diode will still conduct current for certain amount of time. The time period for which the diode conduct. Diode switching characteristicsPN Junction Switching Characteristics A p-n junction is the metallurgical boundary between the n and p-regions of a semiconductor crystal. P-n junctions consist of two semiconductor regions of opposite type. Such junctions show a pronounced rectifying behavior. They are also called p-n diodes in analogy with vacuum diodes. The p-n junction is a versatile element, which can be used as

Also known as a diode. One of the basics of semiconductor technology Created by placing n-type and p-type material in. close contact. Diffusion - mobile charges (holes) in p-type combine. with mobile charges (electrons) in n-type. fP-N JUNCTION Description O Tunnel diode is a semi-conductor with a special characteristic of negative resistance. O By negative resistance, we mean that when voltage is increased, the current through it decreases. O Highly doped PN- junction. Doping density of about 1000 times greater than ordinary junction diode. 3 Forward bias LED Light-emitting Diode Charge carriers recombination takes place at the p-n junction as electron crosses from the n-side and recombines with holes on the p-side. When the junction is forward-biased the free electron is in the conduction band and is at a higher energy level than the hole located at valence band V-I Characteristics of PN Junction Diode. VI characteristics of PN junction diodes is a curve between the voltage and current through the circuit. Voltage is taken along the x-axis while the current is taken along the y-axis. The above graph is the VI characteristics curve of the PN junction diode Switching Diode. This is a normal single PN junction diode which is especially designed for switching purposes. This diode can exhibit two states of high and low resistance clearly which can be used alternatively. The junction capacitance of this diode is made very low so as to minimize other effects. The switching speed is made quite high

### Pn junction diode - SlideShar

1. al device, the characteristics of diode depends on the polarity of the external potential applied to the PN junction diode. The junction of N and P semiconductors is free of charge carriers; hence the region is called as depletion region. The width of depletion region alters with the external applied potential
2. Analog Electronics: V-I Characteristics of PN Junction DiodeTopics Covered:1. Volt-ampere characteristics of diode in forward bias condition.2. Volt-ampere c..
3. al of the pn junction is at a higher potential than the cathode, the flow of current occurs from positive to negative as.

### PN Junction Diode - PowerPoint Slides - LearnPic

6.2.1 Diode Characteristics. A p-n junction diode can be used as a switch. When the diode is forward-biased, the switch is said to be in the ON state and when it is reverse-biased, the switch is in the OFF state. Figure 6.1 shows the V-I characteristic of a p-n junction diode. The diode current is given by the relation: where, V is the bias. Lecture Series on Basic Electronics by Dr.Chitralekha Mahanta, Department of Electronics and Communication Engineering ,IIT Guwahati. For more details on NPT.. Chapter 6-1. PN-junction diode: I-V characteristics Topics: PN Junction under bias (qualitative discussion) Ideal diode equation Deviations from the ideal diode - A free PowerPoint PPT presentation (displayed as a Flash slide show) on PowerShow.com - id: 4222a9-NGE2 From the foregoing discussion the i-v characteristics of a p-n junction diode can be drawn as shown in Fig 2.2. While drawing this characteristics the ohmic drop in the bulk of the semiconductor body has been neglected. Fig 2.2: Volt-Ampere ( i-v) characteristics of a p-n junction diode Exercise 2.1 (1) Fill in the blanks with the appropriate. Doping and Impurities (Donors or Acceptors) P-type and N-type Material. 7. 6-2 Junction Diode - A free PowerPoint PPT presentation (displayed as a Flash slide show) on PowerShow.com - id: 1f61bc-ZDc1Z. PN-junction diodes: working of diode, characteristics and applications of varactor diode.

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• 3. Do not switch ON the power supply unless you have checked the circuit connections as per the circuit diagram. Inference: 1. In the forward biased mode the zener diode operates as a p-n diode. 2. In the reverse biased mode zener diode has large breakdown voltage and though the current increases the voltage remains constant
• The P-N junction diodes have two regions which are the P-type and N-type. The electrons will flow from the n-side to the p-side only when there is an increase in the voltage. Similarly, holes from the p-side will move to the n-side only when the voltage applied to the P-type material is increased. In simpler words, a push is required to move.
• P-N Junction Diode: A P-N Junction Diode is one of the simplest semiconductor devices around, and which has the characteristic of passing current in only one direction only. However, unlike a resistor, a diode does not behave linearly with respect to the applied voltage as the diode has an exponential current-voltage ( I-V ) relationship
• 0 is a constant depending on the pn junction geometry and V 0 is the built-in voltage of the diode (see chapter Semiconductor Materials: pn junction). 1.1.2 Forward Bias When the diode is forward-biased through a voltageV, a small drift current ﬂows again across the junction. In that case, however, there is an additional component, the.
• Characteristics of an ideal diode: Non-Conduction Region Look at the horizontal line! In the non-conduction region, ideally • all of the voltage is across the diode, • the current is 0A, • the reverse resistance (R R) is defined as R R = V R /I R, • the diode acts like open.
• Household Electronics Diodes & Rectification Component Identification Diodes Diodes are essentially one-way current gates Symbolized by: Current vs. voltage graphs: Diode Makeup Diodes are made of semiconductors (usually silicon) Essentially a stack of p-doped and n-doped silicon to form a p-n junction doping means deliberate impurities that contribute extra electrons (n-doped) or holes.

This page of application notes section covers PN junction diode applications. This P-N diode applications are very useful for beginners. As shown in the figure, PN junction diode is a 2 terminal polarity sensitive device. The diode conducts when forward bias is applied and it will introduce zero resistance in the circuit A reverse biased pn junction diode acts like an open switch and blocks the flow of current from anode to cathode. Points To Remember. A forward biased pn junction diode acts like a closed switch provided the forward biasing voltage must be greater than its barrier potential. The width of depletion region decreases with increase in forward bias The main dynamic characteristics of diodes are the reverse recovery time trr, and the static capacitance Ct. trr is the time when, from the state in which a voltage is applied in the forward direction and forward current IF is flowing, the voltage is changed to the reverse direction and the reverse current IR returns to the steady state (essentially zero)

Switching characteristics dv/dt capability Charge Characteristics Gate charge Calculation of Total Gate Charge Source-Drain Characteristics Body Diode Characteristics dv/dt Capability of the Body Diode Table of Contents ©2019 Power Electronic vertical p-n junction. Capacitance characteristics Power BJT Switching. Characteristics Transient Model of BJT Capacitance Effect • A forward-biased pn - junction exhibits two parallel capacitances: a depletion-layer capacitance and a diffusion capacitance. • A reverse-biased pn-junction has only depletion capacitance. • Under transient conditions, they influence th DIODE Seminar PPT and PDF Report Download: A diode is also a tool that exclusively permits unidirectional flow of current if the diode is operated at a particular voltage level.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 voltage at that this breakdown happens is termed. The total time required by the diode which is the sum of ts and tt to recover. completely from the change of state. trr=ts+tt. trr depends on RC time constant ,where C transition capacitance of diode. Total switching time trr limits on the maximum operating frequency of the. diode Diode Switching Characteristics (Reverse Recovery Characteristics): We have already discussed about the Power diode basic s and Power diode Structur e in our previous posts. In this post let us see the dynamic characteristics of the power diode

### PN-Junction Diode Characteristics ppt - Documentatio

Practical diodes cannot act as perfect conductor and perfect insulator. Ideal diode draws no current when reverse biased. Practical diode draws very low current when reverse biased. Ideal diode offers infinite resistance when reverse biased. Practical diode offers very high resistance when reverse biased. It cannot be manufactured The P-N junction diode appeared in the year 1950. It is the most essential and the basic building block of the electronic device. The PN junction diode is a two-terminal device, which is formed when one side of the PN junction diode is made with p-type and doped with the N-type material Static resistance or DC resistance of a PN junction diode defines the diode's resistive nature when a DC source is connected to it. If an external DC voltage is given to the circuit in which the semiconductor diode is a part of it, results in a Q-point or operating point on the PN junction diode characteristic curve that does not alter with time EC8252 - ELECTRONIC DEVICES ED Regulation 2017 UNIT I SEMICONDUCTOR DIODE. PN junction diode, Current equations, Energy Band diagram, Diffusion and drift current densities, forward and reverse bias characteristics, Transition and Diffusion Capacitances, Switching Characteristics, Breakdown in PN Junction Diodes

P-N Junction Diode: Now, if we join the two types of semi-conductors P-type and N-type together then a new device is formed called as P-N junction diode. Since a junction forms between a P type and N type material it is called as P-N junction. The word diode can be explained as 'Di' means two and 'ode' is obtained from electrode Lecture 20: PN diodes (forward bias), small signal model, BJTs Prof J. S. Smith Department of EECS University of California, Berkeley EECS 105 Spring 2004, Lecture 20 Prof. J. S. Smith Context This lecture will discuss zDiode Currents in forward and reverse bias (6.1-6.3) zSmall signal models for diodes And if we have some time, we will start I am really excited by the amazing comments & responses I got for my two articles on PN Junction. If you have not read them yet, here they are - 1) Understanding the PN Juction and 2) PN Junction Diode Characteristics. In those 2 articles, I have tried to demystify PN Juction and explain it in very simple words. From those good responses, I assume my attempt has been successful to some extent VD1 is a switching diode in the circuit, and its function is equivalent to a switch, which is used to switch on and off the capacitor C2. Fast recovery diode It is mainly used in switching power supplies, PWM pulse width modulators, inverters and other electronic circuits, as a high-frequency rectifier diode, freewheeling diode or damping diode A diode is also used as a Switch. It helps a faster ON and OFF for the output that should occur in a quick rate. V - I Characteristics of a Diode. A Practical circuit arrangement for a PN junction diode is as shown in the following figure

The Light Emitting Diode or LED as it is more commonly called, is basically just a specialised type of diode as they have very similar electrical characteristics to a PN junction diode. This means that an LED will pass current in its forward direction but block the flow of current in the reverse direction PN Junction Diodes. When a crystal of semiconductor is doped such that half the portion of the crystal is doped with a trivalent impurity and the other half is doped with a pentavalent impurity, then the junction (boundary) formed is called a PN junction. The crystal itself is called a semiconductor diode or a solid-state diode

### Diode v i characteristic - SlideShar

• electric voltage to the p-n junction. This leads to our discussion of diodes, in the next section. 4. Diodes  In simple terms, a diode is a device that restricts the direction of flow of charge carriers (electrons in this class) . Essentially, it allows an electric current to flow in one direction, but blocks it in the opposite direction
• al connected to the P-region is called Anode while the ter
• PN Junction diode . If one side of a single crystal of pure semiconductor (Ge or Si) is doped with acceptor impurity atoms and the other side is doped with donor impurity atoms, a PN junction is formed as shown in Fig. P region has a high concentration of holes and N region contains a large number of electrons
• Schottky diodes. Schottky diodes are constructed of a metal-to-N junction rather than a P-N semiconductor junction.Also known as hot-carrier diodes, Schottky diodes are characterized by fast switching times (low reverse-recovery time), low forward voltage drop (typically 0.25 to 0.4 volts for a metal-silicon junction), and low junction capacitance.. The schematic symbol for a Schottky diode is.
• In regular diodes (also known as signal diode), the doping level of both P and N sides is the same and hence we get a PN junction, but in power diodes, we have a junction formed between a heavily doped P + and a lightly doped N - the layer which is epitaxially grown on a heavily doped N + layer. Hence the structure looks as shown in the figure below
• Photo diode, as the name implies, is a PN junction which works on light. The intensity of light affects the level of conduction in this diode. The photo diode has a P type material and an N-type material with an intrinsic material or a depletion region in between. This diode is generally operated in reverse bias condition

I Principle of Zener diodes. Zener diodes are diodes that act as regulators.By using the reverse breakdown state of the PN junction, the current of the Zener diodes can be changed within a wide range while the voltage is unchanged.This diode is a semiconductor device with very high resistance up to the critical reverse breakdown voltage. At this critical breakdown point, the reverse resistance. Schottky diodes are most common PN junction diodes used in analog electronics. It is a simple diode that contain P and N junction but has a fast switching action and a low forward voltage drop. 5. Ions do not move in a PN junction. a) True b) False Answer: a Clarification: Ions does not move in a PN junction. They are immobile

The junctions which formed where n-type and p-type semiconductors are joined together is called p-n junction. Diode. A semiconductor diode is a device typically made up of a single p-n junction. The junction of a p-type and n-type semiconductor forms a depletion region where current conduction is reserved by the lack of mobile charge carriers The advantage is a PN junction is needed to make a diode, electronic type. But the main advantage it can be used to aid in converting AC to DC that is required for most electronics. Also the diode can be used as an electronic switch with the prope.. Unlike conventional diodes that provide diode characteristics through a PN (semiconductor-semiconductor) junction, Schottky barrier diodes utilize a Schottky barrier consisting of a metal-semiconductor junction.This results in much lower V F characteristics (forward voltage drop) compared with a PN junction diodes, enabling faster switching speeds. . However, one drawback is larger leakage. A diode is made from a combination of only two layers that is why there is only one PN junction as well as only one depletion region. The transistor is constituted of 3 alternating layers. Therefore, there are 2 PN junctions as well as 2 depletion regions. Switching. The diode can perform switching but it is in an uncontrolled manner The Energy-band diagram versus voltage for the metal-semiconductor Junction shown in Fig.3 is very similar to these of the p-n junction. Because of similarity, we expect the current-voltage characteristics of the Schottky barrier junction to be similar to the exponential behavior of the p-n junction diode

### Diode - SlideShar

• Zener diode definition. A zener diode is a p-n junction semiconductor device designed to operate in the reverse breakdown region. The breakdown voltage of a zener diode is carefully set by controlling the doping level during manufacture. The name zener diode was named after the American physicist Clarance Melvin Zener who discovered the zener.
• al device while the transistor is the three ter
• ority carrier
• PN Junction A PN junction has rectifying current-voltage (I-V or IV) characteristics as shown in Fig. 4-2. As a device, it is called a rectifier or a diode. The PN junction is the basic structure of solar cell, light-emitting diode, and diode laser, and is present in all types of transistor
• al to the p-side of pn junction diode and then connect the negative ter
• Lecture 15 - The pn Junction Diode (I) I-V Characteristics November 1, 2005 Contents: 1. pn junction under bias 2. I-V characteristics Reading assignment: Howe and Sodini, Ch. 6, §§6.1-6.3. 6.012 - Microelectronic Devices and Circuits - Fall 2005 Lecture 15-2 Key question

PN junction 。- 。- 。- Junction capacitor influences the switching characteristics of power diode. Junction capacitor Diffusion capacitor CD Potential barrier capacitor CB. Power E l e ct r o n i cs 22 Static characteristics of power diode The I-V characteristic of power diode I O I F U TO UF U. Power E l e ct r o n i cs 23 Switching. PN Junction Diode : Theory of PN diode, energy band diagram of PN diode, PN junction as a diode, operation and V-I characteristics , static and dynamic resistances, diode equivalent circuits, diffusion and transition capacitance, diode current equation, temperature dependence of V-I characteristics, Zener diode characteristics ,break down. A typical power diode has P-I-N structure, that is, it is a P-N junction with a near-intrinsic semiconductor layer (I-layer) in the middle to sustain reverse vol tage. Figure 1.1 shows the diode symbol and its volt-ampere characteristics. In the forward-biased condition, the diode can be represented by a junction offset drop and a series-equivalen Diode Characteristics Conduction Region Non-Conduction Region • The voltage across the diode is 0 V • All of the voltage is across the diode • The current is infinite • The current is 0 A • The forward resistance is defined as • The reverse resistance is defined as RF = VF / IF RR = VR / IR • The diode acts like a short • The. Premature breakdown may occur at edges of diodes. Premature breakdown mitigation requires edge engineering: high field at edge direct edge contact n metal overlap n moat n guard ring p p n If p guard ring used, must make sure that p-n junction never turns on. In essence, this is a 2D or 3D problem

2.3 Reverse recovery characteristics of SiC-SBD Si fast P-N junction diodes (e.g. FRDs: fast recovery diodes) have high transient current at the moment the junction voltage switches from the forward to the reverse direction, resulting in significant switching loss 2.3 Switching Power PN diodes have a memory effect due to the storage of minority carriers. If the voltage across a diode which has been conducting in the forward direction is suddenly reversed, the p and n regions of the diode are still full of minority carriers, which can cause the diode to behave like a short circuit fo Diode - symbol • An ideal diode - 2 terminal device and act as a switch, can conduct current only in 1 direction P N Anode Cathode Diodes packages I-V Characteristic - Ideal Forward Bias region The voltage across the diode is 0V The current is infinite The diode acts a short Reverse Bias region All of the voltage is across the is 0V The. Volt-ampere (V-I) characteristics of a pn junction or semiconductor diode is the curve between voltage across the junction and the current through the circuit. Normally the voltage is taken along the x-axis and current along y-axis. The circuit connection for determining the V-I characteristics of a pn junction is shown in the figure below. The. ### Types of diode - SlideShar

Diode •A diode is a 2 lead semiconductor that acts as a one way gate to electron flow. - Diode allows current to pass in only one direction. •A pn-junction diode is formed by joining together n-type and p-type silicon. •In practice, as the n-type Si crystal is being grown, the process is abruptly altered to grow p-type Si crystal Lecture 16 - The pn Junction Diode (II) Equivalent Circuit Model November 3, 2005 Contents: 1. I-V characteristics (cont.) 2. Small-signal equivalent circuit model 3. Carrier charge storage: diﬀusion capacitance Reading assignment: Howe and Sodini, Ch. 6, §§6.4, 6.5, 6.9 Announcements: Quiz 2: 11/16, 7:30-9:30 PM

### Electronic Circuits - Diode as a Switch - Tutorialspoin

• als (namely anode and cathode) semiconductor switching device. It is also called as four layer diode. It functions like a normal diode without any trigger inputs, in reverse biased condition, no current flows through it and in forward biased condition current flows through it.
• This is a special type of diode in which a PN junction is replaced by a metal semiconductor junction. The P-type semiconductor in a normal PN junction diode is replaced by a metal and N-type material is joined to the metal. This combination has no depletion region between them. The following figure shows the Schottky diode and its symbol
• Chapter 1 Chapter 1 INTRODUCTION INTRODUCTION - #308: Back to Basics: Diodes - guide to operation, characteristics, types - #82: How to use a Diode as a Switch / Diodes as Switches - band gap and semiconductors - Semiconductors (Intrinsic/Extrinsic, P-Type/N-Type) - How do semiconductors work - pn junction - diode forward biased part2-level-part-3 - pn junction part-1 (youTube) - diode.
• The PIN diode receives its name from the fact that is has three main layers. Rather than just having a P type and an N type layer, the PIN diode has three layers: P-type layer; Intrinsic layer; N-type layer; The instrinic layer of the PIN diode is the one that provides the change in properties when compared to a normal PN junction diode
• Also, unlike signal diodes, these operate at lower switching speeds. Basics of PN junction. The fundamental entity that is responsible for the operation of various power semiconductor devices is a p-n junction. Even in signal diodes, we have seen that a p-n junction is formed by physical contact between p and n-type semiconductor materials
• PIN diode PIN diode The PIN diode operates as variable resistance at RF and microwave frequencies. The resistance value of the PIN diode is is inversely proportional to the DC bias current. A PIN diode obeys the standard diode equation for low frequency signals (at low f, the charge can be removed and the diode turns off). At higher frequencies, there is not enough time to remove the charge.

### PN junction (Diode) Switching Characteristics - YouTub

The PN junction • Biasing the PN junction • The diode • Trouble Shooting . Key Words: Semiconductor, Silicon, PN Junction, Forward Bias, Reverse Bias, Diode . ET212 Electronics - Semiconductors . Floyd . 2 . Introduction . Introduction. Forward bias Current flows Reverse Bias No current flow . The basic function of a diode is to. Switching Characteristics A Schottky diode turns on and turns off faster than a comparable pn-junction diode. The basic reason is that Schottky diodes are majority-carrier devices and have no stored minority carriers that must be injected into the device during turn-on and pulled out durin The diodes across the transistors' base-emitter junctions prevent negative input voltages from causing reverse breakdown of the PN junction. Note that these diodes are reverse-biased for positive input voltages, but conduct if the base voltage reaches - 0.6V     Diode PN Junction Fig 2.0.4 Diode Depletion Layer When P and N type silicon are brought together during manufacture, a junction is created where the P type and N type materials meet, and holes close to the junction in the P type silicon are attracted into negatively charged N type material at the other side of the junction Diode. tutorials we saw that simple diodes are made up from two pieces of semiconductor material, either silicon or germanium to form a simple PN-junction and we also learnt about their properties and characteristics. If we now join together two individual signal diodes back-to-back, this will give us two PN-junctions connected together i  2. Large Signal Diode. These diodes have large PN junction layer. Thus, they are usually used in rectification i.e., converting AC to DC. The large PN Junction also increases the forward current carrying capacity and reverse blocking voltage of the diode. The large signal diodes are not suitable for high frequency applications Tunnel diode shows a negative resistance in their operating range. So, it can be used as amplifier, oscillators and in any switching circuits. Width of the Depletion Region in Tunnel Diode. When mobile charge carriers both free electrons and holes are missing, the region in a p-n junction has a region called Depletion region But, the characteristics of crystal diode is different from the characteristics of the PN-junction diode. In the forward bias condition, the resistance of the point contact diode is high compared to the general PN-junction diode. In the reverse bias condition, in case of point contact diode, the flow of current through the diode is not as. PN junction Diode plays a vital role in our electronic fields, because of their unique property (current flows in only one direction) they are used in many electronic or electrical circuits like rectifiers, switches, clippers, clampers, voltage multipliers.. In this article, we will learn about what is a PN Junction Diode and how it Works and also effect on PN Junction diode with different. The characteristics so generated resembles the characteristics of the tunnel diode. The operation of the diode takes place in reverse biasing mode thus, it is called backward diode. Circuit Symbol of Backward Diode. The circuit symbol of a backward diode is a slightly modified symbol of a conventional P-N diode