This document describes characteristics of PN junction diodes and their usage as rectifiers. It discusses:
1) How a PN junction is formed and its depletion region. Forward and reverse biasing causes majority carrier flow or inhibits diffusion current.
2) Diode operation characteristics including the ideal switch model and practical model with 0.7V forward voltage drop. Breakdown occurs above the reverse voltage rating.
3) How diodes can be used as half-wave and full-wave rectifiers to convert AC to DC, including equations for output voltage and peak inverse voltage requirements.
Basic electronics and electrical first year engineeringron181295
The document provides information on p-n junction diodes and their characteristics:
- A p-n junction is formed at the boundary between p-type and n-type semiconductor materials. When joined, electrons and holes diffuse across the junction forming a depletion region.
- Diodes can be forward or reverse biased by applying an external voltage. In forward bias, current flows through the majority carriers. In reverse bias, the depletion region widens preventing majority carrier flow, but some minority carrier current still flows.
- The V-I characteristics of a diode show regions of forward conduction, reverse saturation current, and breakdown. Key parameters are forward voltage drop, reverse breakdown voltage, and dynamic resistance.
Total slides: 102
Depletion Layer in PN Junction
Barrier Potential in a PN junction
Energy Diagram of PN Junction
Biasing The PN Junction
V-I Characteristics of P-N junction Diode
Applications of Diode - Rectiers
Photodiode
Light Emitting Diodes - LED
Zener Diode
The document discusses PN junction diodes and their applications. It describes how a PN junction forms and its electrical characteristics. Different types of diodes are covered, including Zener diodes and light emitting diodes. Circuit applications of diodes such as rectification, voltage regulation, and signal processing are explained through examples. Key diode properties like forward and reverse biasing, turn-on voltage, and dynamic resistance are defined. Diode models from ideal to linear element are also introduced.
1) A PN junction diode allows large numbers of electrons and holes to flow under forward bias when the depletion region collapses. Under reverse bias, it acts as an open switch that blocks most carrier flow.
2) When a PN junction forms, electrons diffuse from the N to P region, leaving positive ions in the N region and negative ions in the P region. This forms the depletion region that sets up an electric field.
3) A diode's V-I characteristic shows large forward current above the knee voltage but small reverse saturation current below the breakdown voltage, with the ideal diode approximated as a closed switch above and open below the knee voltage.
This document provides an overview of semiconductor diodes, including PN junction diodes. It discusses intrinsic and extrinsic semiconductors, doping to create N-type and P-type materials, the PN junction, depletion region and built-in voltage calculations. Forward and reverse bias characteristics are examined along with current equations. Energy band diagrams are presented for the PN junction under zero, forward and reverse bias. Other topics covered include drift and diffusion current densities, transition and diffusion capacitances, switching characteristics and breakdown mechanisms in PN junction diodes. Ratings for diodes such as maximum current and voltage are also defined.
This document summarizes different types of PN diodes. It begins by explaining the theory of a PN junction, how a PN junction forms a diode, and the ideal characteristics of a diode. It then discusses the volt-current characteristics and biasing of diodes. The rest of the document describes several specific types of diodes - Zener diodes, light emitting diodes, photo diodes, and tunnel diodes. It provides details on their construction, operating principles, and common applications.
Analog Electronics presentation on p-n junction diodeVipin Kumar
The p-n junction is the basic element of bipolar devices like diodes that allows current to flow easily in one direction. It is formed at the interface between p-type and n-type semiconductor materials. When a forward bias is applied, it reduces the potential barrier and allows a large diffusion current to flow. When a reverse bias is applied, it increases the potential barrier and only a very small reverse saturation current can flow. The p-n junction's rectifying property allows it to be used in applications like photodiodes, LEDs, and varactor diodes.
Basic electronics and electrical first year engineeringron181295
The document provides information on p-n junction diodes and their characteristics:
- A p-n junction is formed at the boundary between p-type and n-type semiconductor materials. When joined, electrons and holes diffuse across the junction forming a depletion region.
- Diodes can be forward or reverse biased by applying an external voltage. In forward bias, current flows through the majority carriers. In reverse bias, the depletion region widens preventing majority carrier flow, but some minority carrier current still flows.
- The V-I characteristics of a diode show regions of forward conduction, reverse saturation current, and breakdown. Key parameters are forward voltage drop, reverse breakdown voltage, and dynamic resistance.
Total slides: 102
Depletion Layer in PN Junction
Barrier Potential in a PN junction
Energy Diagram of PN Junction
Biasing The PN Junction
V-I Characteristics of P-N junction Diode
Applications of Diode - Rectiers
Photodiode
Light Emitting Diodes - LED
Zener Diode
The document discusses PN junction diodes and their applications. It describes how a PN junction forms and its electrical characteristics. Different types of diodes are covered, including Zener diodes and light emitting diodes. Circuit applications of diodes such as rectification, voltage regulation, and signal processing are explained through examples. Key diode properties like forward and reverse biasing, turn-on voltage, and dynamic resistance are defined. Diode models from ideal to linear element are also introduced.
1) A PN junction diode allows large numbers of electrons and holes to flow under forward bias when the depletion region collapses. Under reverse bias, it acts as an open switch that blocks most carrier flow.
2) When a PN junction forms, electrons diffuse from the N to P region, leaving positive ions in the N region and negative ions in the P region. This forms the depletion region that sets up an electric field.
3) A diode's V-I characteristic shows large forward current above the knee voltage but small reverse saturation current below the breakdown voltage, with the ideal diode approximated as a closed switch above and open below the knee voltage.
This document provides an overview of semiconductor diodes, including PN junction diodes. It discusses intrinsic and extrinsic semiconductors, doping to create N-type and P-type materials, the PN junction, depletion region and built-in voltage calculations. Forward and reverse bias characteristics are examined along with current equations. Energy band diagrams are presented for the PN junction under zero, forward and reverse bias. Other topics covered include drift and diffusion current densities, transition and diffusion capacitances, switching characteristics and breakdown mechanisms in PN junction diodes. Ratings for diodes such as maximum current and voltage are also defined.
This document summarizes different types of PN diodes. It begins by explaining the theory of a PN junction, how a PN junction forms a diode, and the ideal characteristics of a diode. It then discusses the volt-current characteristics and biasing of diodes. The rest of the document describes several specific types of diodes - Zener diodes, light emitting diodes, photo diodes, and tunnel diodes. It provides details on their construction, operating principles, and common applications.
Analog Electronics presentation on p-n junction diodeVipin Kumar
The p-n junction is the basic element of bipolar devices like diodes that allows current to flow easily in one direction. It is formed at the interface between p-type and n-type semiconductor materials. When a forward bias is applied, it reduces the potential barrier and allows a large diffusion current to flow. When a reverse bias is applied, it increases the potential barrier and only a very small reverse saturation current can flow. The p-n junction's rectifying property allows it to be used in applications like photodiodes, LEDs, and varactor diodes.
The document discusses the basics of a P-N junction diode. It explains that a P-N junction diode is formed by doping one side of an intrinsic semiconductor with an acceptor material to make it P-type and the other side with a donor material to make it N-type. When unbiased, electron-hole pairs diffuse across the junction but are stopped by the depletion region. When forward biased, the depletion region decreases and carriers can flow across the junction. The current-voltage characteristics show that in forward bias the current increases exponentially with voltage, while in reverse bias the current is very small until breakdown occurs.
1. The document discusses the V-I characteristics of a p-n junction diode and describes its behavior under zero external voltage, forward bias, and reverse bias.
2. Rectifiers are introduced as circuits that convert AC to DC. Half-wave and full-wave rectifiers are described, including their circuit arrangements and operations. Centre-tap and bridge configurations are covered for full-wave rectification.
3. Zener diodes are discussed as properly doped diodes with a sharp breakdown voltage. They are always connected in reverse bias and have a defined zener voltage.
This document defines key terms related to semiconductors and diodes. It explains that semiconductors have conductivity properties between conductors and insulators. Doping adds impurities to semiconductors to increase charge carriers, which are electrons in N-type materials and holes in P-type materials. A diode has an anode and cathode, and conventional current flows from negative to positive terminals. When a diode is forward biased with positive to P-type and negative to N-type, the junction barrier is reduced and current flow is maximum.
Pn junction diode class 12 investegatory projectabhijeet singh
The document is a physics investigatory project report on P-N junction diodes submitted by Abhijeet Kumar Singh of class XII. It includes an acknowledgment section thanking various people for their support and guidance. The content sections cover diode theory, zero bias, reverse bias, forward bias, breakdown region, useful diode parameters and ideal versus real junction diode characteristics. Diagrams are included to illustrate the concepts. References and websites used for the project are listed at the end.
The presentation explains working of pn junction diode, V-I characteristics, breakdown mechanism, ac and dc resistance, diode capacitance, effect of temperature and equivalent circuit. It also covers special diodes, LED, Varicap diodes, Tunnel diode, and working of LCD
This document summarizes key topics related to electronics devices and circuits, including:
1) The operation and characteristics of unbiased, forward biased, and reverse biased diodes. Forward biasing reduces the depletion region and allows current to flow, while reverse biasing increases the depletion region and prevents current.
2) Breakdown mechanisms including avalanche and Zener effects which allow current to flow under high reverse voltages.
3) Energy bands and levels that describe the quantum mechanical states of electrons in materials, and how semiconductor materials have a forbidden gap between valence and conduction bands.
4) How the barrier potential of a p-n junction decreases with increasing temperature, allowing more current to flow.
LEDs (light-emitting diodes) are semiconductor devices that emit light when activated. They work by passing electricity through two opposing materials (p-type and n-type semiconductor), causing electrons to recombine with electron holes and release energy in the form of photons. Common applications of LEDs include indicator lights, displays, traffic lights and signs, lighting (replacing incandescent bulbs), and backlighting for LCDs.
1. The document discusses the physical principles of semiconductor diodes and diode circuits, including N-type and P-type semiconductors, the PN junction, and biasing of the PN junction.
2. It describes how a PN junction forms a diode that allows current to flow in only one direction, and how forward and reverse biasing affects the junction.
3. The document also covers Zener diodes and their use in voltage regulator circuits to provide a stable output voltage despite changes in the input voltage.
The document discusses the operation and properties of a p-n junction diode. It describes how a p-n junction is formed at the boundary between p-type and n-type semiconductors. When forward biased, majority carriers are pushed towards the junction, lowering the barrier and allowing current to flow. When reverse biased, the depletion region widens, increasing resistance and preventing current flow. P-n junction diodes are fundamental components used in various electronic devices.
Semiconductor Diode :
What is Semiconductor Diode?
How is it Work?
What are the Types?
Current Flow in Forward And Reverse Bios?
What is Light Emitting Diode (LED)?
What is Zener Diode?
and in aditional :
P-N Junction and its formation
Formation of Depletion Layer
External Biasing of P-N Junction
V-I Characteristics of P-N Junction
Zener Breakdown
Avalanche Breakdown
Comparison between Zener and Avalanche Breakdown
A p-n junction is formed where a single crystal of silicon or germanium is doped such that one half is p-type semiconductor and the other half is n-type semiconductor. When forward biased, the barrier potential decreases allowing majority charge carriers to flow across the junction, decreasing resistance. When reverse biased, the barrier potential increases preventing carrier flow and increasing resistance. The voltage-current characteristics of a p-n junction diode are nonlinear, with negligible current below the threshold voltage and exponential increase in current above it. In reverse bias, very little reverse saturation current flows until the breakdown voltage is exceeded.
The attached narrated power point presentation explains the construction, working and applications of PN Junction Diodes. The material will be useful for KTU first year students who prepare for the subject EST 130, Part B, Basic Electronics Engineering.
This document summarizes key concepts about semiconductor diodes:
- Diodes are electronic devices created by joining a p-type and n-type semiconductor, allowing current to flow easily in one direction. They are used for rectification in circuits.
- P-type materials have an excess of holes, making them positively charged, while N-type materials have an excess of electrons, giving them a negative charge.
- Diodes conduct current easily when forward biased by applying positive voltage to the p-side and negative to the n-side. They do not conduct in the reverse biased state.
- The Shockley diode equation models the current-voltage relationship of an ideal diode based on thermal voltage and
This document discusses the characteristics and operation of a PN diode. It describes:
1) How a PN diode is formed by joining P-type and N-type materials, and the three biasing possibilities: no bias, forward bias, and reverse bias.
2) Under no bias, there is no current flow. Under forward bias, the depletion region decreases and current rises exponentially. Under reverse bias, there is only a small reverse saturation current.
3) The diode current-voltage relationship and how it changes under different biasing conditions. Forward bias leads to an exponential rise in current above the potential barrier voltage.
The document summarizes different types of semiconductor diodes. It discusses the theory of p-n junctions and how a p-n junction forms a diode. It describes the ideal behavior of a diode under forward and reverse bias. The characteristics of a diode are shown in its volt-current curve. Different types of diodes are described briefly, including Zener diodes, light emitting diodes, photo diodes, and their uses.
The document discusses diodes, including their history and components. It describes how a diode is constructed from a P-type and N-type semiconductor material, forming a PN junction. At the junction, electrons diffuse into holes, creating a depletion region that acts as an insulator under reverse bias but allows current to flow under forward bias. The document outlines diode applications such as rectification in power supplies and their characteristic I-V curve.
Semiconductors like silicon and germanium can be used to create diodes and transistors. A diode allows current to pass in only one direction, acting like a one-way valve. By adding impurities to an intrinsic semiconductor, n-type and p-type materials can be created. A PN junction diode consists of an n-type and p-type material joined together. Diodes can be used in rectifier circuits to convert AC to DC and in voltage regulators. Zener diodes operate in the reverse breakdown region to provide a stable reference voltage.
This ppt is about semiconductor diodes.You can get every basic information about PN junction diode and its working and some more information about the semiconductors.
The semiconductor diode is formed from a p-n junction between doped p-type and n-type semiconductor materials, which creates a depletion region that blocks current flow in reverse bias but allows it in forward bias. In forward bias, majority carriers recombine near the junction, reducing the depletion width and allowing an exponential increase in current; in reverse bias, carriers move away to widen the depletion region, only permitting small minority carrier currents. The diode's current-voltage relationship follows the diode equation, where current increases exponentially with forward voltage but remains very small in reverse bias.
This document provides information about PN junction diodes and their characteristics:
1) It describes how a PN junction is formed by combining P-type and N-type semiconductors, forming a depletion region.
2) It explains the I-V characteristics of a diode under forward and reverse bias, including how the depletion region changes with bias.
3) Additional topics covered include drift and diffusion currents, temperature effects, capacitance effects, and recovery time characteristics important for switching applications. Special diodes like Zener diodes are also introduced.
The document discusses the basics of a P-N junction diode. It explains that a P-N junction diode is formed by doping one side of an intrinsic semiconductor with an acceptor material to make it P-type and the other side with a donor material to make it N-type. When unbiased, electron-hole pairs diffuse across the junction but are stopped by the depletion region. When forward biased, the depletion region decreases and carriers can flow across the junction. The current-voltage characteristics show that in forward bias the current increases exponentially with voltage, while in reverse bias the current is very small until breakdown occurs.
1. The document discusses the V-I characteristics of a p-n junction diode and describes its behavior under zero external voltage, forward bias, and reverse bias.
2. Rectifiers are introduced as circuits that convert AC to DC. Half-wave and full-wave rectifiers are described, including their circuit arrangements and operations. Centre-tap and bridge configurations are covered for full-wave rectification.
3. Zener diodes are discussed as properly doped diodes with a sharp breakdown voltage. They are always connected in reverse bias and have a defined zener voltage.
This document defines key terms related to semiconductors and diodes. It explains that semiconductors have conductivity properties between conductors and insulators. Doping adds impurities to semiconductors to increase charge carriers, which are electrons in N-type materials and holes in P-type materials. A diode has an anode and cathode, and conventional current flows from negative to positive terminals. When a diode is forward biased with positive to P-type and negative to N-type, the junction barrier is reduced and current flow is maximum.
Pn junction diode class 12 investegatory projectabhijeet singh
The document is a physics investigatory project report on P-N junction diodes submitted by Abhijeet Kumar Singh of class XII. It includes an acknowledgment section thanking various people for their support and guidance. The content sections cover diode theory, zero bias, reverse bias, forward bias, breakdown region, useful diode parameters and ideal versus real junction diode characteristics. Diagrams are included to illustrate the concepts. References and websites used for the project are listed at the end.
The presentation explains working of pn junction diode, V-I characteristics, breakdown mechanism, ac and dc resistance, diode capacitance, effect of temperature and equivalent circuit. It also covers special diodes, LED, Varicap diodes, Tunnel diode, and working of LCD
This document summarizes key topics related to electronics devices and circuits, including:
1) The operation and characteristics of unbiased, forward biased, and reverse biased diodes. Forward biasing reduces the depletion region and allows current to flow, while reverse biasing increases the depletion region and prevents current.
2) Breakdown mechanisms including avalanche and Zener effects which allow current to flow under high reverse voltages.
3) Energy bands and levels that describe the quantum mechanical states of electrons in materials, and how semiconductor materials have a forbidden gap between valence and conduction bands.
4) How the barrier potential of a p-n junction decreases with increasing temperature, allowing more current to flow.
LEDs (light-emitting diodes) are semiconductor devices that emit light when activated. They work by passing electricity through two opposing materials (p-type and n-type semiconductor), causing electrons to recombine with electron holes and release energy in the form of photons. Common applications of LEDs include indicator lights, displays, traffic lights and signs, lighting (replacing incandescent bulbs), and backlighting for LCDs.
1. The document discusses the physical principles of semiconductor diodes and diode circuits, including N-type and P-type semiconductors, the PN junction, and biasing of the PN junction.
2. It describes how a PN junction forms a diode that allows current to flow in only one direction, and how forward and reverse biasing affects the junction.
3. The document also covers Zener diodes and their use in voltage regulator circuits to provide a stable output voltage despite changes in the input voltage.
The document discusses the operation and properties of a p-n junction diode. It describes how a p-n junction is formed at the boundary between p-type and n-type semiconductors. When forward biased, majority carriers are pushed towards the junction, lowering the barrier and allowing current to flow. When reverse biased, the depletion region widens, increasing resistance and preventing current flow. P-n junction diodes are fundamental components used in various electronic devices.
Semiconductor Diode :
What is Semiconductor Diode?
How is it Work?
What are the Types?
Current Flow in Forward And Reverse Bios?
What is Light Emitting Diode (LED)?
What is Zener Diode?
and in aditional :
P-N Junction and its formation
Formation of Depletion Layer
External Biasing of P-N Junction
V-I Characteristics of P-N Junction
Zener Breakdown
Avalanche Breakdown
Comparison between Zener and Avalanche Breakdown
A p-n junction is formed where a single crystal of silicon or germanium is doped such that one half is p-type semiconductor and the other half is n-type semiconductor. When forward biased, the barrier potential decreases allowing majority charge carriers to flow across the junction, decreasing resistance. When reverse biased, the barrier potential increases preventing carrier flow and increasing resistance. The voltage-current characteristics of a p-n junction diode are nonlinear, with negligible current below the threshold voltage and exponential increase in current above it. In reverse bias, very little reverse saturation current flows until the breakdown voltage is exceeded.
The attached narrated power point presentation explains the construction, working and applications of PN Junction Diodes. The material will be useful for KTU first year students who prepare for the subject EST 130, Part B, Basic Electronics Engineering.
This document summarizes key concepts about semiconductor diodes:
- Diodes are electronic devices created by joining a p-type and n-type semiconductor, allowing current to flow easily in one direction. They are used for rectification in circuits.
- P-type materials have an excess of holes, making them positively charged, while N-type materials have an excess of electrons, giving them a negative charge.
- Diodes conduct current easily when forward biased by applying positive voltage to the p-side and negative to the n-side. They do not conduct in the reverse biased state.
- The Shockley diode equation models the current-voltage relationship of an ideal diode based on thermal voltage and
This document discusses the characteristics and operation of a PN diode. It describes:
1) How a PN diode is formed by joining P-type and N-type materials, and the three biasing possibilities: no bias, forward bias, and reverse bias.
2) Under no bias, there is no current flow. Under forward bias, the depletion region decreases and current rises exponentially. Under reverse bias, there is only a small reverse saturation current.
3) The diode current-voltage relationship and how it changes under different biasing conditions. Forward bias leads to an exponential rise in current above the potential barrier voltage.
The document summarizes different types of semiconductor diodes. It discusses the theory of p-n junctions and how a p-n junction forms a diode. It describes the ideal behavior of a diode under forward and reverse bias. The characteristics of a diode are shown in its volt-current curve. Different types of diodes are described briefly, including Zener diodes, light emitting diodes, photo diodes, and their uses.
The document discusses diodes, including their history and components. It describes how a diode is constructed from a P-type and N-type semiconductor material, forming a PN junction. At the junction, electrons diffuse into holes, creating a depletion region that acts as an insulator under reverse bias but allows current to flow under forward bias. The document outlines diode applications such as rectification in power supplies and their characteristic I-V curve.
Semiconductors like silicon and germanium can be used to create diodes and transistors. A diode allows current to pass in only one direction, acting like a one-way valve. By adding impurities to an intrinsic semiconductor, n-type and p-type materials can be created. A PN junction diode consists of an n-type and p-type material joined together. Diodes can be used in rectifier circuits to convert AC to DC and in voltage regulators. Zener diodes operate in the reverse breakdown region to provide a stable reference voltage.
This ppt is about semiconductor diodes.You can get every basic information about PN junction diode and its working and some more information about the semiconductors.
The semiconductor diode is formed from a p-n junction between doped p-type and n-type semiconductor materials, which creates a depletion region that blocks current flow in reverse bias but allows it in forward bias. In forward bias, majority carriers recombine near the junction, reducing the depletion width and allowing an exponential increase in current; in reverse bias, carriers move away to widen the depletion region, only permitting small minority carrier currents. The diode's current-voltage relationship follows the diode equation, where current increases exponentially with forward voltage but remains very small in reverse bias.
This document provides information about PN junction diodes and their characteristics:
1) It describes how a PN junction is formed by combining P-type and N-type semiconductors, forming a depletion region.
2) It explains the I-V characteristics of a diode under forward and reverse bias, including how the depletion region changes with bias.
3) Additional topics covered include drift and diffusion currents, temperature effects, capacitance effects, and recovery time characteristics important for switching applications. Special diodes like Zener diodes are also introduced.
The document provides information about bipolar junction transistors (BJT) and semiconductor diodes. It begins with definitions of key BJT and diode terms, such as drift current, diffusion current, depletion region, and diode current equation. It then discusses the structure and characteristics of PN junction diodes, including forward and reverse bias operation and their V-I characteristics. Applications of diodes are also listed. The document derives expressions for diffusion current density and the diode current equation. It explains diode switching characteristics like recovery time and examines the working and characteristics of PN junction diodes in detail.
Electrical current, voltage, resistance, capacitance, and inductance are a few of the basic elements of electronics and radio. Apart from current, voltage, resistance, capacitance, and inductance, there are many other interesting elements to electronic technology. ... Use Electronics Notes to learn electronics online.
Minor project report on pn junction, zener diode, led characteristicsom prakash bishnoi
This document provides an overview of PN junction diodes, including their construction, operating principles, and I-V characteristics under forward and reverse bias conditions. In forward bias, the depletion region narrows allowing electrons and holes to flow across the junction, resulting in a lower resistance path. In reverse bias, the depletion region widens inhibiting flow and resulting in a very small saturation current until breakdown. The document explains the diffusion, drift, and recombination processes that occur under equilibrium and biasing conditions.
This document provides an overview of semiconductor devices and digital logic circuits. It discusses:
1. Semiconductors including intrinsic and extrinsic types, N-type and P-type materials, and the energy band structure.
2. PN junction diodes including the theory of operation, I-V characteristics under forward and reverse bias, and applications as rectifiers.
3. Bipolar junction transistors (BJTs) including transistor biasing and operation.
4. Digital logic circuit design including realization of logic expressions using gates, combinational logic design methods like SOP and POS forms, Karnaugh maps, and introduction to FPGAs.
A PN junction is formed by joining a P-type semiconductor with an N-type semiconductor. When joined, majority charge carriers diffuse across the junction, creating a depletion layer empty of mobile charges. This layer acts as an insulator. When forward biased, the depletion layer narrows, allowing current to flow. When reverse biased, the layer widens, blocking nearly all current flow. The I-V characteristic of a PN junction diode shows it acts as a rectifier, allowing current in only one direction. Diodes have applications in rectification, switching, and light emission.
This document provides an overview of semiconductors, diodes, transistors, and power devices. It discusses the energy band structure of semiconductors and classifications of intrinsic, n-type, and p-type semiconductors. The document then covers the theory and characteristics of PN junction diodes under forward and reverse bias conditions. Applications of diodes as rectifiers, clippers, and clampers are also discussed. Bipolar junction transistors and their biasing are introduced. Finally, the document discusses types of power converters including AC to DC converters using diode rectifiers and phase controlled rectifiers, as well as DC to DC converters.
The document discusses semiconductor diodes and their applications. It explains how a p-n junction is formed and the barrier potential that is set up. It describes the forward and reverse biasing of diodes and how this affects conduction. The voltage-current characteristics of ideal diodes and real diodes are examined. Applications of diodes include rectification, clipping, and clamping in circuits. Half-wave and full-wave rectifier circuits are explained.
The document discusses the theory of solids, specifically semiconductors, conductors, and insulators. It describes the energy band structure and forbidden energy gaps that determine whether a material is a semiconductor, conductor, or insulator. It also discusses PN junction diodes, their I-V characteristics, and applications in rectifiers. Transistors are also briefly introduced.
CA1-ELECTRONICS ENGINEERING ON PN JUNCTION.pdfsumansafui97
This document discusses the working principle of a PN junction diode. It begins by introducing P-type and N-type semiconductors and how a PN junction is formed when they are joined. It then explains the voltage-current characteristics of a PN junction diode under zero bias, forward bias, and reverse bias conditions. Key points include that a small current flows under reverse bias due to minority carriers, while forward bias reduces the potential barrier allowing current to increase sharply. Applications mentioned are rectification, switching, voltage regulation, and signal conversion.
The document discusses the P-N junction, which is formed at the interface between P-type and N-type semiconductors. It describes how doping the semiconductors with different impurities results in an excess or deficiency of electrons or holes. When the P and N-type materials are joined, charge carriers diffuse across the junction, leaving an electric field. This P-N junction exhibits rectifying behavior and has applications in diodes and transistors. The document also examines the I-V characteristics of a P-N junction diode under forward, reverse, and zero bias conditions.
Thermionic (vacuum tube) diodes and solid state (semiconductor) diodes were developed separately in the early 1900s as radio receiver detectors. Vacuum tube diodes were more commonly used in radios until the 1950s due to early semiconductor diodes being less stable. Semiconductor diodes are made from materials like silicon and germanium that have precise atomic structures that allow controlled current flow. A p-n junction is formed at the interface between p-type and n-type semiconductor materials and enables diode rectification properties. Diodes have various applications including rectification, clamping, clipping, and lighting.
This document provides information about electronic devices and circuits, including energy band structures of insulators, semiconductors and metals; PN junction diodes; bipolar junction transistors; field effect transistors; and operational amplifiers. It discusses the construction, operation, characteristics and applications of these components. The key topics covered include intrinsic and extrinsic semiconductors, forward and reverse bias of PN junctions, transistor biasing configurations, JFET and MOSFET operation, and inverting and non-inverting op-amp circuits.
A PN junction is formed by joining a P-type semiconductor with an N-type semiconductor. When joined, a depletion layer forms at the junction that acts as an insulator. When forward biased, current flows easily through the junction. When reverse biased, very little current flows due to the high resistance of the depletion layer acting as a barrier. PN junction diodes are used as rectifiers, switches, detectors, and light emitting diodes (LEDs) in electronic circuits.
The document discusses PN junction diodes, rectifiers, and bridge rectifiers. It begins by explaining the history and workings of PN junction diodes, including the depletion region and forward/reverse biasing. It then covers half-wave and full-wave rectifiers for converting AC to DC. Finally, it describes bridge rectifiers, including their types, working principle, advantages of higher output voltage and efficiency over center-tap rectifiers, and applications in power supplies.
The document discusses tunnel diodes and their operation. It explains that tunnel diodes use quantum tunneling effects to allow electrons to pass through a potential barrier. The document then provides energy band diagrams and descriptions of tunnel diode operation under forward and reverse bias. It discusses their applications as oscillators, switches, logic devices and amplifiers. The document also compares tunnel diodes to conventional PN diodes and describes other specialized electronic devices like varactor diodes and photodiodes.
1. The document appears to be a student's physics project on building a half-wave rectifier circuit.
2. It includes a cover page with the student's name and school, a certificate signed by his teacher confirming completion of the project, and sections discussing the objectives, components, theory, and procedure of building the circuit.
3. The core of the project describes how a half-wave rectifier works, only allowing the positive half of the AC waveform to pass through the diode to the load resistance, thereby producing pulsating DC output.
The document discusses several special purpose electronic devices:
1. Tunnel diodes use the quantum mechanical effect of tunneling to allow electrons to pass through a thin potential barrier, enabling very fast operation into the microwave frequency region.
2. Varactor diodes have a capacitance that can be varied by changing the reverse bias voltage, making them useful for tuning radio frequency circuits.
3. Photodiodes convert light into an electric current or voltage, using the photoelectric effect to generate electron-hole pairs when photons strike the p-n junction. They are used in light sensors, optocouplers, and optical communications.
4. SCRs are thyristors that act as electrically controlled switches, conducting
Redefining brain tumor segmentation: a cutting-edge convolutional neural netw...IJECEIAES
Medical image analysis has witnessed significant advancements with deep learning techniques. In the domain of brain tumor segmentation, the ability to
precisely delineate tumor boundaries from magnetic resonance imaging (MRI)
scans holds profound implications for diagnosis. This study presents an ensemble convolutional neural network (CNN) with transfer learning, integrating
the state-of-the-art Deeplabv3+ architecture with the ResNet18 backbone. The
model is rigorously trained and evaluated, exhibiting remarkable performance
metrics, including an impressive global accuracy of 99.286%, a high-class accuracy of 82.191%, a mean intersection over union (IoU) of 79.900%, a weighted
IoU of 98.620%, and a Boundary F1 (BF) score of 83.303%. Notably, a detailed comparative analysis with existing methods showcases the superiority of
our proposed model. These findings underscore the model’s competence in precise brain tumor localization, underscoring its potential to revolutionize medical
image analysis and enhance healthcare outcomes. This research paves the way
for future exploration and optimization of advanced CNN models in medical
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Chap 2
1. 1
Chapter Two
Diode Characteristics
2.1. PN Junction
2.2. Diode Operations
2.3. PN Diode as a Rectifier
2.4. Zener Diode Characteristics
2.5. LED and Photo Diode
2.1 PN Junction
The region where the block of p- type material is joined to a block of n- type material is called a
PN junction and is a fundamental component of many electronic devices, including diode,
transistors and others. Remember that diffusion current flows whenever there is a surplus of
carriers in one region and a corresponding lack of carriers of the same kind in another region.
Consequently, at the instant the P and N blocks are joined, electrons from the N region diffuse into
the P region, and holes from the P region diffuse into the N region. (Recall that this hole current is
actually the repositioning of holes due to the motion of valence band electrons.)
For each electron that leaves the N region to cross the junction into the P region, a donor atom that
now has a net positive charge is left behind. Similarly, for each hole that leaves the P region (that
is, for each acceptor atom that captures an electron), an acceptor atom acquires a net negative
charge. The upshot of this process is that negatively charged donor atoms accumulate just inside
the p region, and positively charged donor atoms accumulate just inside the N region. This charge
distribution often called space charge.
Depletion region
Figure 2.1: The PN junction showing charged ions after hole and electron diffusion
Ē
P N
Hole
Electron
2. 2
It is well known that accumulation of electric charge of opposite polarities in two separated regions
cause an electric field to be established between those regions. The accumulation of positive ions
in N material and negative ions in the P material established an electric field across a PN junction.
The direction of field is from the positive N region to the negative P region. Figure 2.1 illustrates
the field Ē developed across a PN junction.
The accumulation of negative charge in the p region prevents additional negative charge from
entering that region (like charges repel each other) and, similarly, the positively charged N region
repels additional positive charge. Therefore, after the initial surge of charge across the junction,
the diffusion current dwindles (becoming gradually less) to a negligible amount.
The direction of electric field across the PN junction enables the flow of drift current from the P
to the N region, that is, the flow of electrons from left to right and of holes from right to left, in
figure 2.1. There is therefore a small drift of minority carriers in opposite direction from the
diffusion current. When equilibrium condition has been established, the small reverse drift current
exactly cancels the diffusion current from N to P. the net current across the junction is therefore
zero.
Remember that the P-region holes have been annihilated by electrons, and the N-region electrons
have migrated to the P side. Because all charge carriers have been depleted (removed) from this
region, it is called the depletion region. It is also called barrier region because the electric field
their acts as a barrier to further diffusion current.
The values of barrier potential, VO, depends on the doping levels in the P and N regions, the type
of material (Si and Ge), and the temperature.
VO =
𝐾𝑇
𝑞
ln
𝑁𝐴 𝑁𝐷
𝑛𝑖2 (2.1)
Where, VO = barrier potential,
K = Boltzmann’s constant = 1.38 × 10−23
J/0
k,
T = temperature of the material in Kelvin (0
k = 273 + 0
c),
q = electron charge = 1.6 × 10−19
c
NA = acceptor doping density in the P material,
ND = donor doping density in the N material
3. 3
𝑛𝑖 = intrinsic electron density.
VT =
KT
q
(2.2)
Where, VT = thermal voltage
2.1.1 Forward – biased junction
When an external dc source is connected across a PN junction, the polarity of the connection can
be such that it either opposes or reinforces the barrier. Suppose a voltage source VD is connected
as shown in figure-2.2, with its positive terminal attached to the P side of a PN junction and its
negative terminal attached to the N side. With polarity of connections shown in the figure 2.2, the
external source creates an electric field component across the junction whose direction opposes
the internal field established by the space charge.
In other words, the barrier is reduced, so diffusion current is enhanced. Therefore, current flows
with relative ease through the junction, its direction of flow is from P to N, as shown in figure 2.2.
In this case the junction is said to be forward biased.
h = hole; ē = electron
Figure 2.2: Forward-biased p-n junction, Narrow depletion width
When the PN junction is forward biased, electrons are forced into the N region by the external
source and holes are forced into the P region. As free electrons move toward the junction through
the N material, a corresponding number of holes progresses through the P material. Thus, current
in each region is the result of majority carrier flow. Electrons diffuse through the depletion region
and recombine with holes in the P material. For each hole that recombines with an electron, an
electron from a covalent bond leaves the P region and enters the positive terminal of the external
source, thus maintaining the equality of current entering and leaving the source. Since there is a
reduction in the electric field barrier at the forward- biased junction, there is a corresponding
Ē
h ē
4. 4
reduction in the quantity of ionized acceptor and donor atoms required to maintain the field. As a
result, the depletion region narrows under forward bias.
2.1.2 Reverse - biased junction
When the positive terminal of the source is connected to the N side of the junction and the negative
terminal is connected to the P side (shown in figure 2.3) the polarity of the bias voltage reinforces,
or strengthens, the internal barrier field at the junction. Consequently, diffusion current is inhibited
to an even greater extent than it was with no bias applied. The increased field intensity must be
supported by an increase in the number of ionized donor and acceptor atoms, so the depletion
regions widen under reverse bias.
Figure 2.3: Reverse - biased p-n junction, wide depletion region
Recall that, the unbiased PN junction has a component of drift current consisting of minority
carriers that cross the junction from the P to the N side. This reverse current is the direct result of
the electric field across the depletion region. Since a reverse – biasing voltage increases the
magnitude of that field, we can expect the reverse current to increases correspondingly. The current
magnitude is very much smaller than the current that flows under forward bias.
The distinction between the ways a PN junction reacts to a bias voltage, very little current flow
when it is reverse biased and substantial current flow when it is forward biased, makes it very
useful device in many circuit applications.
2.2 Diode operation
Diode is made up of 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. The p region is called the anode and is connected to a conductive terminal. The n region
5. 5
is called the cathode and is connected to a second conductive terminal. The basic diode structure
and schematic symbol are shown in Figure 2–4 given below.
Figure 2.4 schematic symbol of diode.
2.2.1 Characteristics of ideal & practical diode
Understanding the operation of the semiconductor diode is the basis for an understanding of all
semiconductor devices. It is the simplest of semiconductor devices but plays a very vital role in
electronic systems, having characteristics that closely match those of a simple switch. The term
ideal refers to any device or system that has ideal characteristics perfect in every way. The ideal
diode is a two-terminal device having the symbol and characteristics shown in figure 2.5, a and b
respectively. The characteristics of an ideal diode are those of a switch that can conduct current in
only one direction.
Figure 2.5 Conduction (a) and non-conduction (b) state of Ideal diode
The P side of the diode is called its anode and the N side is called its cathode.
ID = IS (𝑒
𝑉𝐷
𝜂𝑉𝑇 − 1) (2.3)
ID = current; VD = voltage (positive for forward bias and negative for reverse bias).
IS = saturation current; η = emission coefficient; VT = thermal voltage.
6. 6
Figure 2.6: I-V relations in a PN junction under forward and reverse bias
1) A silicon diode has a reverse saturation current of 7.12nA at room temperature of 27oc.
Calculate its forward current if it is forward biased with a voltage of 0.7v.
Solution: The given values are
Is = 7.2nA, K=1.38*10e-23 J/K, Q = 1.6*10-19 C
V = + 0.7 v as forward biased.
𝜂 = 2 for silicon diode
T = 270
𝐶 = 27 + 273 = 3000
𝐾
Now VT = KT/q = 8.62 x 10-5 x 300 = 0.026 v
Using diode current equation,
I = 4.99 x 10-3A = 5mA. Thus, the forward current is 5mA.
I) The Ideal Diode Model
The ideal model of a diode is the least accurate approximation and can be represented by a simple
switch as shown in the figure 2.7 below.
Figure 2.7 V-I characteristics of ideals diodes
7. 7
When the diode is forward-biased, it ideally acts like a closed (on) switch, as shown in Figure 2.7
(a). When the diode is reverse-biased, it ideally acts like an open (off) switch, as shown in part (b).
In Figure 2.7 (c), the ideal V-I characteristic curve graphically depicts the ideal diode operation.
II) The Practical Diode Model
The practical model includes the barrier potential. When the diode is forward-biased, it is
equivalent to a closed switch in series with a small equivalent voltage source (VF) equal to the
barrier potential (0.7 V) with the positive side toward the anode, as indicated in Figure 2.8 (a).
This equivalent voltage source represents the barrier potential that must be exceeded by the bias
voltage before the diode will conduct and is not an active source of voltage. When conducting, a
voltage drop of 0.7 V appears across the diode. When the diode is reverse-biased, it is equivalent
to an open switch just as in the ideal model, as shown in Figure 2.8 (b). The barrier potential does
not affect reverse bias, so it is not a factor. The characteristic curve for the practical diode model
is shown in Figure 2.8 (c).
Figure 2.8 V-I characteristics of practical diodes
2.2.2 Breakdown
The reverse current also deviates from that predicted by the ideal diode equation if the reverse
biasing voltage is allowed to approach a certain value called the reverse break down voltage, VBR.
A very small increase in reverse bias voltage in the vicinity of VBR results in a very large increase
in reverse current. In other word the diode no longer exhibits its normal characteristics of
maintaining a very small, essentially constant reverse current with increasing reverse voltage.
8. 8
Figure 2.9: a plot of the I-V relation for diode, showing the sudden increase in reverse current
near the reverse break down voltage.
In ordinary diodes, the breakdown phenomenon occurs because the high electric field in the
depletion region impart high kinetic energy (large velocities) to the carriers crossing the region,
and when these carriers collide with other atoms, they rupture covalent bonds.
The large numbers of carriers that are freed in this way accounts for the increase in reverse current
through the junction. The process is called avalanching. The magnitude of the reverse current that
flows when V approaches VBR can be predicted from the relation:
I =
IS
1−[
𝑉
𝑉𝐵𝑅
]𝑛
(2.4)
Where n is a constant determined by experiment and has a value between 2 and 6.
The value of the breakdown voltage depends on doping and other physical characteristics that are
controlled in manufacturing. Ordinary diodes may have breakdown voltage ranging from 10 or 20
to hundreds of volts.
2.3 Diode as a Rectifier
Almost all electronics circuits require a dc source of power. For portable low power systems
batteries may be used. More frequently electronic equipment is energized by a power supply, a
piece of equipment which converts the alternating waveform from the power lines into an essential
direct voltage. A device, such as the semiconductor diode, which is capable of converting a
sinusoidal input waveform (whose average value is zero) into a unidirectional waveform, with a
nonzero average component, is called a rectifier. The process of converting AC to DC waveform
is called rectifications. There are two types of rectifications process:
2.3.1 Half-wave rectification
In half-wave rectification either the positive or negative half of the ac wave is passed, while the
other half is blocked. The basic circuit for half – wave rectification is shown in figure 2.10.
9. 9
Figure 2.10: Half-wave rectifier
Over one full cycle, defined by the period T of figure 2.10, the average value (the algebraic sum
of the areas above and below the axis) of vi is zero.
During the interval t = 0 → T/2 in figure 2.10 the polarity of the applied voltage vi is such as to
establish “pressure” in the direction indicated and turn on the diode with the polarity appearing
above the diode. Substituting the short-circuit equivalence for the ideal diode will result in the
equivalent circuit of figure 2.11, where it is fairly obvious that the output signal is an exact replica
of the applied signal. The two terminals defining the output voltage are connected directly to the
applied signal via the short-circuit equivalence of the diode.
Figure 2.11: Conduction region (0→ T/2)
For the period T/2 → T, the polarity of the input vi is as shown in figure 2.12 and the resulting
polarity across the ideal diode produces an “off” state with an open-circuit equivalent. The result
is the absence of a path for charge to flow and vo = iR = (0) *R = 0 V for the period T/2 → T. The
input vi and the output vo were sketched together in figure 2.13 for comparison purposes.
10. 10
Figure 2.12: Non-conduction region
The output signal vo now has a net positive area above the axis over a full period and an average
value determined by:
Vdc = 0.318𝑉
𝑚 (2.5)
Figure 2.13: Half-wave rectified signal
Note that the net effect of half – wave circuit is the conversion of an ac voltage into a (pulsating)
dc voltage.
The effect of using a silicon diode with VT = 0.7 V is demonstrated in figure 2.14 for the forward-
bias region. The applied signal must now be at least 0.7 V before the diode can turn “on.” For
levels of vi less than 0.7 V, the diode is still in an open-circuit state and vo = 0 V as shown in the
same figure. When conducting, the difference between vo and vi is a fixed level of VT = 0.7 V and
vo = vi − VT, as shown in the figure 2.14. The net effect is a reduction in area above the axis, which
naturally reduces the resulting dc voltage level.
Figure 2.14: Effect of VT on Half-wave rectified signal
11. 11
For situations where Vm ≫ VT, the average value is determined by Eq.2.6.
𝑉𝑑𝑐 ≅ 0.318(𝑉
𝑚 − 𝑉𝑇 ) (2.6)
The peak inverse voltage (PIV) [or PRV (peak reverse voltage)] rating of the diode is the voltage
rating that must not be exceeded in the reverse-bias region or the diode will enter the Zener
avalanche region. The required PIV rating for the half-wave rectifier can be determined in Eq.2.7.
𝑃𝐼𝑉𝑟𝑎𝑡𝑖𝑛𝑔 ≥ 𝑉
𝑚 (2.7)
2.3.2 Full - wave rectification
A full – wave rectifier effectively inverts the negative half – pulses of a sine wave to produce an
output that is a sequence of positive half – pulses with no intervals between them. It is more
efficient than the half – wave rectifier.
The dc level (average value) obtained from a sinusoidal input can be improved 100% using a
process called full – wave rectification.
Bridge network: it is the most familiar network for performing a full – wave rectification. It is
shown in figure 2.15 with its four diodes in a bridge configuration.
Figure 2.15: Full – wave bridge rectifier
During the period t = 0 to T/2 the polarity of the input is as shown in figure 2.16a. The resulting
polarities across the ideal diodes are also shown in figure 2.16a to reveal that D2 and D3 are
conducting while D1 and D4 are in the “off” state. The net result is the configuration of figure
2.16b, with its indicated current and polarity across R. Since the diodes are ideal the load voltage
is vo = vi, as shown in the same figure.
12. 12
Figure 2.16: (a) Network of figure 2.15 for the period 0 →T/2 of the input voltage vi. (b)
Conduction path for the positive region of vi
For the negative region of the input the conducting diodes are D1 and D4, resulting in the
configuration of figure 2.17. The important result is that the polarity across the load resistor R is
the same as in figure 2.16a, establishing a second positive pulse, as shown in figure 2.17.
Figure 2.17: Conduction path for the negative region of vi
Over one full cycle the input and output voltages will appear as shown in figure 2.18. Since the
area above the axis for one full cycle is now twice that obtained for a half-wave system, the dc
level has also been doubled.
𝑉𝑑𝑐 = 0.636𝑉
𝑚 (2.8)
Figure 2.18: input and output waveform for a full-wave rectifier
If silicon rather than ideal diodes is employed as shown in figure 2.19, an application of
Kirchhoff’s voltage law around the conduction path would result in
𝑣𝑖 − 𝑉𝑇 − 𝑣𝑜 − 𝑉𝑇 = 0
13. 13
𝑣𝑜 = 𝑣𝑖 − 2𝑉𝑇
The peak value of the output voltage vo is therefore
𝑉
𝑜𝑚𝑎𝑥
= 𝑉
𝑚 − 2𝑉𝑇
For situation where Vm≫ 2VT the average value is determined by Eq.2.9
𝑉𝑑𝑐 ≅ 0.636 (𝑉
𝑚 −2𝑉𝑇) (2.9)
Figure 2.19: Determining 𝑉
𝑜𝑚𝑎𝑥
for silicon diodes in the bridge configuration
𝑃𝐼𝑉
𝑓𝑢𝑙𝑙−𝑤𝑎𝑣𝑒 𝑏𝑟𝑖𝑑𝑔𝑒 𝑟𝑒𝑐𝑡𝑖𝑓𝑖𝑒𝑟 ≥ 𝑉
𝑚 (2.10)
2.4 Zener diode
Zener diode is a reverse-biased heavily doped p-n junction diode which is operated in the
breakdown region. The symbol of a Zener diode is shown in figure 2.20a. It is like an ordinary p-
n junction diode except that it is properly doped so as to have a sharp breakdown voltage. When
forward biased, its characteristics are similar to that of an ordinary diode. It is always reverse
biased and has sharp breakdown voltage, called the Zener voltage. By controlling the junction
width and doping densities of diode it is possible to make it to breakdown at a sharp specified
Zener voltage from about 2 to 200 V. A Zener diode is specified by its breakdown voltage and the
maximum power dissipation.
Figure 2.20: (a) Zener diode, (b) the normal operation region of Zener diode is shaded
14. 14
The most common application of a Zener diode is the voltage stabilization. The Zener diode in
breakdown maintains an almost constant voltage across itself over a wide current range. The
complete equivalent circuit of the Zener diode in the Zener region includes a small dynamic
resistance and dc battery equal to the Zener potential, as shown in figure 2.21.
For all applications to follow, however, we shall assume as a first approximation that the external
resistors are much larger in magnitude than the Zener-equivalent resistor and that the equivalent
circuit is simply the one indicated in figure 2.21b.
Figure 2.21: Zener equivalent circuit (a) complete (b) approximate
Zener diodes are most frequently used in regulator networks or as a reference voltage.
2.5 LED, LCD and Photo Diode
2.5.1 Light - Emitting Diodes
The increasing use of digital displays in calculators, watches, and all forms of instrumentation has
contributed to the current extensive interest in structures that will emit light when properly biased.
The two types in common use today to perform this function are the light-emitting diode (LED)
and the liquid-crystal display (LCD). As the name implies, the light-emitting diode (LED) is a
diode that will give off visible light when it is energized. In any forward-biased p-n junction there
is, within the structure and primarily close to the junction, a recombination of holes and electrons.
This recombination requires that the energy possessed by the unbound free electron be transferred
to another state.
In all semiconductor p-n junctions some of this energy will be given off as heat and some in the
form of photons. In silicon and germanium, the greater percentage is given up in the form of heat
and the emitted light is insignificant. In other materials, such as gallium arsenide phosphide
(GaAsP) or gallium phosphide (GaP), the number of photons of light energy emitted is sufficient
15. 15
to create a very visible light source. The process of giving off light by applying an electrical source
of energy is called electroluminescence.
As shown in figure below with its graphic symbol, the conducting surface connected to the p-
material is much smaller, to permit the emergence of the maximum number of photons of light
energy. Note in the figure that the recombination of the injected carriers due to the forward-biased
junction results in emitted light at the site of recombination. There may, of course, be some
absorption of the packages of photon energy in the structure itself, but a very large percentage are
able to leave, as shown in figure.
Figure 2.22: (a) Process of electroluminescence in the LED; (b) graphic symbol
2.5.2 Photodiodes
While LEDs emit light, Photodiodes are sensitive to received light. They are constructed so their
p-n junction can be exposed to the outside through a clear window or lens. In Photoconductive
mode the saturation current increases in proportion to the intensity of the received light. This type
of diode is used in CD players. In Photovoltaic mode, when the p-n junction is exposed to a certain
wavelength of light, the diode generates voltage and can be used as an energy source. This type of
diode is used in the production of solar power.
Figure 2.23: Schematic symbols for photodiodes