This document discusses techniques for characterizing electronic devices, focusing on electrical and electrochemical methods. It provides an overview of Ohm's law and how resistance is established through current-voltage relationships. Resistivity and resistance are defined, and their relationship illustrated through common formulas. Conductance is also introduced. Voltage-current characteristics are described for different materials, including how they can be used to measure conductivity. The 4-probe technique for resistance measurement is compared to the 2-probe method, highlighting how it overcomes limitations like contact resistance and ensures more accurate resistivity measurements.
1. The document describes an experiment to verify Ohm's Law, which states that the current through a conductor is directly proportional to the voltage applied and inversely proportional to the resistance.
2. The experiment involves setting up a circuit with a resistor and voltage source, measuring the current and voltage at different resistances, and showing that a linear relationship exists between current and voltage.
3. The results show that the ratio of voltage to current remains nearly constant at different measurements, and a graph of current versus voltage produces a straight line as expected from Ohm's Law, verifying it experimentally.
3.1 magnetic effect of current carrying conductorNurul Fadhilah
The document discusses electromagnetism and electromagnets. It defines an electromagnet as a temporary magnet created by winding wire into a coil around an iron core, which produces a magnetic field when current passes through. It outlines learning objectives about drawing magnetic field patterns, conducting experiments to study factors affecting magnetic field strength, and describing applications of electromagnets. Examples of applications mentioned are electric bells, circuit breakers, and loudspeakers.
This document discusses inductance and induced electromotive force (emf). It explains that an induced emf is generated in a conductor when it moves through a magnetic field, and that changing the magnetic flux through a coil can induce an emf. It also states that an induced electric field is produced by a changing magnetic flux according to Faraday's law, and that this induced electric field is what drives the motion of conduction electrons. The document provides examples of inductance, self-inductance, and mutual inductance, and discusses how transformers use inductance to change voltages.
The document discusses electric fields and electrostatics. It explains that when objects are rubbed together, electrons are transferred causing objects to become charged. It then discusses Coulomb's law which states that the force between two charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. It provides equations for calculating electric field strength, potential, and force experienced by charges in fields.
Electric charge is a fundamental property of matter that occurs in discrete units and is carried by elementary particles. There are two types of electric charges: positive and negative. Objects with like charges repel each other, while objects with opposite charges attract. Electric charge is always conserved in closed systems according to Coulomb's law. The Lorentz force law describes the combination of electric and magnetic forces on a moving charged particle due to electromagnetic fields. It plays an important role in technologies like cathode ray tubes.
Van de Graff generator uses an insulating belt to transfer static electric charge to a large spherical conductor, allowing it to build up a very high voltage potential. It works by using corona discharge from sharp points to charge the belt, which then induces opposite charges on a collecting comb attached to the sphere. As the belt continuously circulates, more charge is transferred to the sphere, eventually reaching potentials of millions of volts. This high voltage can be used to accelerate subatomic particles for physics research experiments. However, it produces only low currents and has limitations in the maximum voltage possible due to air breakdown.
Maxwell derived a set of equations that unified electricity, magnetism and light as manifestations of electromagnetic waves. His equations predicted that changes in electric and magnetic fields propagate as waves at the speed of light. This supported Maxwell's theory that light itself is an electromagnetic wave. The electromagnetic spectrum encompasses all possible frequencies of electromagnetic waves, from radio waves to gamma rays. Maxwell's equations form the basis for the modern understanding of electromagnetism and optics.
1. The document describes an experiment to verify Ohm's Law, which states that the current through a conductor is directly proportional to the voltage applied and inversely proportional to the resistance.
2. The experiment involves setting up a circuit with a resistor and voltage source, measuring the current and voltage at different resistances, and showing that a linear relationship exists between current and voltage.
3. The results show that the ratio of voltage to current remains nearly constant at different measurements, and a graph of current versus voltage produces a straight line as expected from Ohm's Law, verifying it experimentally.
3.1 magnetic effect of current carrying conductorNurul Fadhilah
The document discusses electromagnetism and electromagnets. It defines an electromagnet as a temporary magnet created by winding wire into a coil around an iron core, which produces a magnetic field when current passes through. It outlines learning objectives about drawing magnetic field patterns, conducting experiments to study factors affecting magnetic field strength, and describing applications of electromagnets. Examples of applications mentioned are electric bells, circuit breakers, and loudspeakers.
This document discusses inductance and induced electromotive force (emf). It explains that an induced emf is generated in a conductor when it moves through a magnetic field, and that changing the magnetic flux through a coil can induce an emf. It also states that an induced electric field is produced by a changing magnetic flux according to Faraday's law, and that this induced electric field is what drives the motion of conduction electrons. The document provides examples of inductance, self-inductance, and mutual inductance, and discusses how transformers use inductance to change voltages.
The document discusses electric fields and electrostatics. It explains that when objects are rubbed together, electrons are transferred causing objects to become charged. It then discusses Coulomb's law which states that the force between two charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. It provides equations for calculating electric field strength, potential, and force experienced by charges in fields.
Electric charge is a fundamental property of matter that occurs in discrete units and is carried by elementary particles. There are two types of electric charges: positive and negative. Objects with like charges repel each other, while objects with opposite charges attract. Electric charge is always conserved in closed systems according to Coulomb's law. The Lorentz force law describes the combination of electric and magnetic forces on a moving charged particle due to electromagnetic fields. It plays an important role in technologies like cathode ray tubes.
Van de Graff generator uses an insulating belt to transfer static electric charge to a large spherical conductor, allowing it to build up a very high voltage potential. It works by using corona discharge from sharp points to charge the belt, which then induces opposite charges on a collecting comb attached to the sphere. As the belt continuously circulates, more charge is transferred to the sphere, eventually reaching potentials of millions of volts. This high voltage can be used to accelerate subatomic particles for physics research experiments. However, it produces only low currents and has limitations in the maximum voltage possible due to air breakdown.
Maxwell derived a set of equations that unified electricity, magnetism and light as manifestations of electromagnetic waves. His equations predicted that changes in electric and magnetic fields propagate as waves at the speed of light. This supported Maxwell's theory that light itself is an electromagnetic wave. The electromagnetic spectrum encompasses all possible frequencies of electromagnetic waves, from radio waves to gamma rays. Maxwell's equations form the basis for the modern understanding of electromagnetism and optics.
The document discusses the Hall effect, which is when a conductor carrying an electric current is placed perpendicular to a magnetic field. This causes the charges in the conductor to experience a force perpendicular to both the current and the magnetic field. This displacement of charges establishes a voltage difference known as the Hall voltage across the conductor. The Hall effect can be used to determine various properties of materials like charge carrier types and densities. Precise measurement techniques like Van der Pauw and Hall coefficient calculations are used to characterize semiconductor samples.
Resistors are used in electric circuits to oppose electric current and are measured in ohms. They have two main characteristics - resistance value and power dissipation capacity. Resistors come in various resistance values and tolerances, and are used for purposes like heating and current limiting. They can be fixed or variable, and fixed resistors include carbon composition, metalized, and wire wound types. Variable resistors have three leads - two fixed and one movable - to allow adjustment of resistance while connected to a circuit.
The document provides an overview of Chapter 32 from the textbook "University Physics" which covers electromagnetic waves. It discusses Maxwell's equations that describe electromagnetic waves and how electromagnetic waves propagate at the speed of light. It also covers how electromagnetic waves occur over a wide range of frequencies and wavelengths, and how they are reflected and refracted as they pass through different materials.
Resistance is defined as the ratio of voltage to current in a circuit. Ohm's law states that voltage is directly proportional to current and resistance. The resistance of an object depends on the material it is made of, with insulators having high resistance and conductors having low resistance. Resistance also depends on size and shape, with resistance increasing as length increases or cross-sectional area decreases. Resistance is measured in ohms and resistance can be calculated using the resistance equation.
Wilhelm Roentgen discovered x-rays in 1895 when he observed that a fluorescent screen glowed near a cathode ray tube. He found that x-rays are produced when electrons collide with a metal target in a vacuum tube. There are two types of x-ray spectra produced: continuous spectra which has a range of wavelengths, and characteristic spectra which consists of peaks produced by electronic transitions within atoms. X-rays can diffract when they interact with the periodic planes of atoms in a crystal according to Bragg's law. The wavelength is determined by the spacing between planes and the diffraction angle. Moseley's law describes the relationship between an element's atomic number and the wavelength of its spectral lines.
1. Current is the flow of electrons through a circuit, measured in amps. Voltage is the electrical pressure that pushes electrons through a circuit, measured in volts. Resistance opposes the flow of electrons and is measured in ohms.
2. Ohm's Law describes the relationship between current, voltage, and resistance in a circuit using the formula E=IR. It can be used to calculate any one variable if the other two are known.
3. Circuits can be connected in series, parallel, or series-parallel configurations which determine how current and voltage are distributed.
This document discusses how various factors affect the resistance of electrical conductors. It states that resistance depends on the length, cross-sectional area, material, and temperature of the conductor. Longer wires, thinner wires, and materials with higher resistivity all result in higher resistance. Additionally, increasing the temperature of a conductor causes its resistance to rise as well. Various materials and their resistivities are listed to illustrate differences. Resistance is directly proportional to length and resistivity, and inversely proportional to cross-sectional area.
Rahil Parsana completed a physics project on a Van de Graaff generator for their class XII examination. The project report acknowledges the guidance of their physics teachers Mr. Kumar Rajesh and Mr. Pawan Singh. It includes an introduction to the Van de Graaff generator, the operating principle of electrostatic induction, descriptions of key components and how it works to generate a high voltage static charge, applications of high voltage generators, and a bibliography citing online and textbook sources.
Current is defined as the rate of flow of electric charge measured in amperes and is calculated using the formula I=Q/T where I is current, Q is electric charge, and T is time. Voltage is defined as potential difference or electromotive force and is calculated using the formula V=E/Q where V is voltage, E is energy, and Q is electric charge. Resistance is defined as the ratio of the potential difference across a component to the current flowing through it and is calculated using the formulas R=V/I or R=ρl/A where R is resistance, V is voltage, I is current, ρ is resistivity, l is length, and A is area. Power is
Fun with electric charge and coulombs lawDevi Sahu
The fun facts about physics related to coulombs law. This slide is to be viewed after learning the basics of Coulombs law in Cerego. Learn here https://cerego.com/sets/745640
Resistivity is a measure of a material's ability to resist electric current flow. It quantifies how strongly a material opposes current. The resistance of a material increases as its resistivity or length increases, and decreases as its area increases. While the resistivity of most conductors increases with temperature, the resistivity of some semiconductors like carbon and silicon decreases with rising temperature due to increased electron mobility.
This document discusses key concepts in electric circuits including potential difference, electromotive force (emf), current, resistance, and how these concepts relate to different circuit configurations. It defines potential difference and emf as the voltage across battery terminals when not or in a complete circuit. Current is defined as the rate of charge flow measured in amperes. Resistance depends on the material and physical characteristics of a circuit element and is measured in ohms. Resistors in series have the same current but their voltages add up, while resistors in parallel have the same voltage but their currents add up. Measuring devices like voltmeters and ammeters must be connected appropriately.
When a dielectric material is placed between the plates of a capacitor, the capacitance increases. This is because the dielectric material becomes polarized in the electric field, resulting in a net separation of positive and negative charges. The polarization is represented by a vector quantity P called the polarization vector. The relative permittivity εr of a material quantifies how much more charge can be stored in a capacitor due to the presence of that material. In covalent solids, electronic polarization occurs due to the displacement of electrons in covalent bonds between atoms in response to an applied electric field.
Ohm's Law explains the relationship between voltage, current, and resistance in a circuit. Voltage is the pressure behind current flow, measured in volts. Current refers to the quantity of electrical flow, measured in amps. Resistance opposes current flow, measured in ohms. According to Ohm's Law, if voltage is constant, increasing resistance decreases current, and decreasing resistance increases current.
The document discusses the classical scattering cross section in mechanics. It begins by introducing scattering cross sections as important parameters in physics. It then discusses central forces and how scattering of particles can be considered under classical central force approximations. The rest of the document derives the classical Rutherford differential scattering cross section formula by analyzing particle scattering via a central force and equating impact parameters with scattering angles and energies. It notes how this classical formula fits real scattering problems well but departs at higher energies, requiring quantum mechanical treatment.
Ferromagnetic materials have three main characteristics:
1) They become spontaneously magnetized in the absence of an external magnetic field due to parallel alignment of magnetic moments.
2) They have a magnetic ordering temperature called the Curie temperature, above which they become paramagnetic.
3) They are used in many devices like transformers, electromagnets, and computer hard drives due to their magnetic properties.
➣ Electron Drift Velocity
➣➣➣ Charge Velocity and
Velocity of Field Propagation
➣➣➣ The Idea of Electric Potential
Resistance
➣➣➣ Unit of Resistance
➣➣➣ Law of Resistance
➣➣➣ Units of Resistivity
Conductance and
Conductivity
➣➣➣ Temperature Coefficient of
Resistance
➣➣➣ Value of α at Different
Temperatures
➣➣➣ Variation of Resistivity with
Temperature
➣➣➣ Ohm’s Law
➣➣➣ Resistance in Series
➣➣➣ Voltage Divider Rule
➣➣➣ Resistance in Parallel
➣➣➣ Types of Resistors
➣➣➣ Nonlinear Resistors
➣➣➣ Varistor
➣➣➣ Short and Open Circuits
➣➣➣ ‘Shorts’ in a Series Circuit
➣➣➣ ‘Opens’ in Series Circuit
➣➣➣ ‘Open’s in a Parallel Circuit
➣➣➣ ‘Shorts’ in Parallel Circuits
➣➣➣ Division of Current in Parallel
Circuits
➣➣➣ Equivalent Resistance
➣➣➣ Duality Between Series and
Parallel Circuits
➣➣➣ Relative Potential
This document outlines the key learning objectives and content covered in Chapter 20 on Electric Circuits. The chapter covers current, resistance, power, Ohm's law, series and parallel circuits, capacitors, and more. The learning objectives are to understand concepts like current, conductivity, resistance, Ohm's law, and how resistors behave in series and parallel combinations. Students should be able to apply concepts like equivalent resistance, voltage division, and Kirchhoff's rules to solve circuit problems. The chapter also covers capacitors and RC circuits.
Gauss's law states that the total electric flux passing through any closed surface is equal to the total charge enclosed by that surface. The mathematical formulation of Gauss's law is given by the integral form, relating the electric flux to the enclosed charge. The differential or point form expresses Gauss's law in terms of the divergence of the electric flux density being equal to the enclosed charge density. Gauss's law can be used to calculate the electric field intensity due to various charge distributions, such as a line charge or an infinite sheet of charge.
This document provides information about Earth's magnetism and magnetic fields. It explains that Earth's magnetic field is generated by a dynamo effect in the planet's liquid iron core, similar to how a bicycle dynamo works. It also defines key terms related to magnetism, including uniform and non-uniform magnetic fields, magnetic field lines, magnetic poles, dipoles, permeability, and susceptibility. The document discusses how Earth's magnetic field behaves similarly to a bar magnet and protects the planet, while hot temperatures cause metals to lose their magnetic properties.
- The document reports on an experiment investigating the limitations of electrical measurement devices like analog and digital multimeters.
- It was determined that the internal resistance of an analog ammeter was 0.504 ± 0.024 Ω. The voltage readings of a digital multimeter were found to be most accurate for measuring sinusoidal electrical quantities.
- The experiment analyzed the accuracy of different devices in measuring values like voltage, current, resistance, and more under various circuit conditions.
This document provides details on measuring the resistance of semiconductors using the four probe method and how it varies with temperature. It first explains Ohm's law and the two probe method for measuring resistance. The four probe method is then introduced to overcome issues with contact resistance. The document derives equations to calculate resistivity based on probe spacing and sample thickness/boundaries. Finally, it discusses how the intrinsic conductivity of semiconductors increases with temperature due to more electrons occupying the conduction band, following an exponential relationship, and how carrier mobility decreases with increasing temperature due to more collisions.
The document discusses the Hall effect, which is when a conductor carrying an electric current is placed perpendicular to a magnetic field. This causes the charges in the conductor to experience a force perpendicular to both the current and the magnetic field. This displacement of charges establishes a voltage difference known as the Hall voltage across the conductor. The Hall effect can be used to determine various properties of materials like charge carrier types and densities. Precise measurement techniques like Van der Pauw and Hall coefficient calculations are used to characterize semiconductor samples.
Resistors are used in electric circuits to oppose electric current and are measured in ohms. They have two main characteristics - resistance value and power dissipation capacity. Resistors come in various resistance values and tolerances, and are used for purposes like heating and current limiting. They can be fixed or variable, and fixed resistors include carbon composition, metalized, and wire wound types. Variable resistors have three leads - two fixed and one movable - to allow adjustment of resistance while connected to a circuit.
The document provides an overview of Chapter 32 from the textbook "University Physics" which covers electromagnetic waves. It discusses Maxwell's equations that describe electromagnetic waves and how electromagnetic waves propagate at the speed of light. It also covers how electromagnetic waves occur over a wide range of frequencies and wavelengths, and how they are reflected and refracted as they pass through different materials.
Resistance is defined as the ratio of voltage to current in a circuit. Ohm's law states that voltage is directly proportional to current and resistance. The resistance of an object depends on the material it is made of, with insulators having high resistance and conductors having low resistance. Resistance also depends on size and shape, with resistance increasing as length increases or cross-sectional area decreases. Resistance is measured in ohms and resistance can be calculated using the resistance equation.
Wilhelm Roentgen discovered x-rays in 1895 when he observed that a fluorescent screen glowed near a cathode ray tube. He found that x-rays are produced when electrons collide with a metal target in a vacuum tube. There are two types of x-ray spectra produced: continuous spectra which has a range of wavelengths, and characteristic spectra which consists of peaks produced by electronic transitions within atoms. X-rays can diffract when they interact with the periodic planes of atoms in a crystal according to Bragg's law. The wavelength is determined by the spacing between planes and the diffraction angle. Moseley's law describes the relationship between an element's atomic number and the wavelength of its spectral lines.
1. Current is the flow of electrons through a circuit, measured in amps. Voltage is the electrical pressure that pushes electrons through a circuit, measured in volts. Resistance opposes the flow of electrons and is measured in ohms.
2. Ohm's Law describes the relationship between current, voltage, and resistance in a circuit using the formula E=IR. It can be used to calculate any one variable if the other two are known.
3. Circuits can be connected in series, parallel, or series-parallel configurations which determine how current and voltage are distributed.
This document discusses how various factors affect the resistance of electrical conductors. It states that resistance depends on the length, cross-sectional area, material, and temperature of the conductor. Longer wires, thinner wires, and materials with higher resistivity all result in higher resistance. Additionally, increasing the temperature of a conductor causes its resistance to rise as well. Various materials and their resistivities are listed to illustrate differences. Resistance is directly proportional to length and resistivity, and inversely proportional to cross-sectional area.
Rahil Parsana completed a physics project on a Van de Graaff generator for their class XII examination. The project report acknowledges the guidance of their physics teachers Mr. Kumar Rajesh and Mr. Pawan Singh. It includes an introduction to the Van de Graaff generator, the operating principle of electrostatic induction, descriptions of key components and how it works to generate a high voltage static charge, applications of high voltage generators, and a bibliography citing online and textbook sources.
Current is defined as the rate of flow of electric charge measured in amperes and is calculated using the formula I=Q/T where I is current, Q is electric charge, and T is time. Voltage is defined as potential difference or electromotive force and is calculated using the formula V=E/Q where V is voltage, E is energy, and Q is electric charge. Resistance is defined as the ratio of the potential difference across a component to the current flowing through it and is calculated using the formulas R=V/I or R=ρl/A where R is resistance, V is voltage, I is current, ρ is resistivity, l is length, and A is area. Power is
Fun with electric charge and coulombs lawDevi Sahu
The fun facts about physics related to coulombs law. This slide is to be viewed after learning the basics of Coulombs law in Cerego. Learn here https://cerego.com/sets/745640
Resistivity is a measure of a material's ability to resist electric current flow. It quantifies how strongly a material opposes current. The resistance of a material increases as its resistivity or length increases, and decreases as its area increases. While the resistivity of most conductors increases with temperature, the resistivity of some semiconductors like carbon and silicon decreases with rising temperature due to increased electron mobility.
This document discusses key concepts in electric circuits including potential difference, electromotive force (emf), current, resistance, and how these concepts relate to different circuit configurations. It defines potential difference and emf as the voltage across battery terminals when not or in a complete circuit. Current is defined as the rate of charge flow measured in amperes. Resistance depends on the material and physical characteristics of a circuit element and is measured in ohms. Resistors in series have the same current but their voltages add up, while resistors in parallel have the same voltage but their currents add up. Measuring devices like voltmeters and ammeters must be connected appropriately.
When a dielectric material is placed between the plates of a capacitor, the capacitance increases. This is because the dielectric material becomes polarized in the electric field, resulting in a net separation of positive and negative charges. The polarization is represented by a vector quantity P called the polarization vector. The relative permittivity εr of a material quantifies how much more charge can be stored in a capacitor due to the presence of that material. In covalent solids, electronic polarization occurs due to the displacement of electrons in covalent bonds between atoms in response to an applied electric field.
Ohm's Law explains the relationship between voltage, current, and resistance in a circuit. Voltage is the pressure behind current flow, measured in volts. Current refers to the quantity of electrical flow, measured in amps. Resistance opposes current flow, measured in ohms. According to Ohm's Law, if voltage is constant, increasing resistance decreases current, and decreasing resistance increases current.
The document discusses the classical scattering cross section in mechanics. It begins by introducing scattering cross sections as important parameters in physics. It then discusses central forces and how scattering of particles can be considered under classical central force approximations. The rest of the document derives the classical Rutherford differential scattering cross section formula by analyzing particle scattering via a central force and equating impact parameters with scattering angles and energies. It notes how this classical formula fits real scattering problems well but departs at higher energies, requiring quantum mechanical treatment.
Ferromagnetic materials have three main characteristics:
1) They become spontaneously magnetized in the absence of an external magnetic field due to parallel alignment of magnetic moments.
2) They have a magnetic ordering temperature called the Curie temperature, above which they become paramagnetic.
3) They are used in many devices like transformers, electromagnets, and computer hard drives due to their magnetic properties.
➣ Electron Drift Velocity
➣➣➣ Charge Velocity and
Velocity of Field Propagation
➣➣➣ The Idea of Electric Potential
Resistance
➣➣➣ Unit of Resistance
➣➣➣ Law of Resistance
➣➣➣ Units of Resistivity
Conductance and
Conductivity
➣➣➣ Temperature Coefficient of
Resistance
➣➣➣ Value of α at Different
Temperatures
➣➣➣ Variation of Resistivity with
Temperature
➣➣➣ Ohm’s Law
➣➣➣ Resistance in Series
➣➣➣ Voltage Divider Rule
➣➣➣ Resistance in Parallel
➣➣➣ Types of Resistors
➣➣➣ Nonlinear Resistors
➣➣➣ Varistor
➣➣➣ Short and Open Circuits
➣➣➣ ‘Shorts’ in a Series Circuit
➣➣➣ ‘Opens’ in Series Circuit
➣➣➣ ‘Open’s in a Parallel Circuit
➣➣➣ ‘Shorts’ in Parallel Circuits
➣➣➣ Division of Current in Parallel
Circuits
➣➣➣ Equivalent Resistance
➣➣➣ Duality Between Series and
Parallel Circuits
➣➣➣ Relative Potential
This document outlines the key learning objectives and content covered in Chapter 20 on Electric Circuits. The chapter covers current, resistance, power, Ohm's law, series and parallel circuits, capacitors, and more. The learning objectives are to understand concepts like current, conductivity, resistance, Ohm's law, and how resistors behave in series and parallel combinations. Students should be able to apply concepts like equivalent resistance, voltage division, and Kirchhoff's rules to solve circuit problems. The chapter also covers capacitors and RC circuits.
Gauss's law states that the total electric flux passing through any closed surface is equal to the total charge enclosed by that surface. The mathematical formulation of Gauss's law is given by the integral form, relating the electric flux to the enclosed charge. The differential or point form expresses Gauss's law in terms of the divergence of the electric flux density being equal to the enclosed charge density. Gauss's law can be used to calculate the electric field intensity due to various charge distributions, such as a line charge or an infinite sheet of charge.
This document provides information about Earth's magnetism and magnetic fields. It explains that Earth's magnetic field is generated by a dynamo effect in the planet's liquid iron core, similar to how a bicycle dynamo works. It also defines key terms related to magnetism, including uniform and non-uniform magnetic fields, magnetic field lines, magnetic poles, dipoles, permeability, and susceptibility. The document discusses how Earth's magnetic field behaves similarly to a bar magnet and protects the planet, while hot temperatures cause metals to lose their magnetic properties.
- The document reports on an experiment investigating the limitations of electrical measurement devices like analog and digital multimeters.
- It was determined that the internal resistance of an analog ammeter was 0.504 ± 0.024 Ω. The voltage readings of a digital multimeter were found to be most accurate for measuring sinusoidal electrical quantities.
- The experiment analyzed the accuracy of different devices in measuring values like voltage, current, resistance, and more under various circuit conditions.
This document provides details on measuring the resistance of semiconductors using the four probe method and how it varies with temperature. It first explains Ohm's law and the two probe method for measuring resistance. The four probe method is then introduced to overcome issues with contact resistance. The document derives equations to calculate resistivity based on probe spacing and sample thickness/boundaries. Finally, it discusses how the intrinsic conductivity of semiconductors increases with temperature due to more electrons occupying the conduction band, following an exponential relationship, and how carrier mobility decreases with increasing temperature due to more collisions.
The document outlines the objectives, outcomes, and units of an Elements of Electrical and Electronics Engineering course. The objectives are to study basic electric circuits, electrical machines, electrical energy applications, and semiconductor devices. The outcomes are to analyze electrical circuits, test electric machines, understand electric power uses, and apply semiconductor principles. The six units cover topics like electrical circuits, DC machines, AC circuits, AC machines, power systems, and electronics devices and digital circuits. Materials for electrical engineering are classified as conductors, semiconductors, insulators, and magnetic materials based on their properties and applications. Circuit elements can be categorized as linear/nonlinear, active/passive, and bilateral/unilateral.
Engineers use Ohm's law to calculate how electrical components like wiring, capacitors, and resistors affect power transmission in circuits. Ohm's law describes the relationship between voltage (V), resistance (R), and current (I) in a circuit. It states that the current through a conductor is directly proportional to the voltage applied and inversely proportional to the resistance of the conductor. Engineers can use Ohm's law to determine how changes to the components of an electrical circuit, like changing the resistance, will impact the voltage and current.
Electrical measurements and two probe methodBEENAT5
This document discusses electrical measurements and resistivity. It begins by defining electrical measurements and noting that resistivity measurements can be studied using different techniques. It then explains concepts like Ohm's law, resistance, and resistivity. Two common methods for measuring resistance are described: the two-probe method and four-probe method. The two-probe method is outlined, but it is noted to have issues with contact resistance and affecting intrinsic resistivity. The four-probe method is proposed to overcome the problems with the two-probe method.
1. The student conducted an experiment to determine the variation of resistivity in different materials. Resistivity was measured for aluminum wire, copper wire, iron wire, and manganin wire.
2. Calculations were shown to determine the resistivity for each material using measurements of resistance, length, thickness, and area.
3. The resistivity increased in the order of aluminum wire, copper wire, iron wire, and manganin wire respectively. This follows the known trend that metals have lower resistivity than alloys.
This document summarizes an experiment on Ohm's Law and finding the resistance of unknown resistors. In part A, the resistance was held constant at 100 ohms while the voltage was varied from 3V to 12V to measure current. Then voltage was held at 10V while resistance was varied to measure current. The measured values aligned well with theoretical calculations using Ohm's Law. In part B, resistors of varying values were used in series and the current and reciprocal of current were measured and graphed. The graph's slope provided the resistance and the y-intercept was zero, confirming Ohm's Law. Minor differences between measured and theoretical values were due to factors like resistor degradation over multiple uses.
1. The document discusses electronic components and focuses on resistors. It describes different types of resistors including fixed resistors like carbon composition, wire wound, and metal film as well as variable resistors.
2. Resistors are used to limit current or divide voltages in circuits. Fixed resistors have a set resistance value while variable resistors can be adjusted.
3. The document provides details on resistor specifications, manufacturing, color coding, and applications.
Resistivity of semiconductor by four probe method.pptxAadityaPandey16
This document describes measuring the resistivity of semiconductors using the four-probe method. It explains that semiconductors have electrical conductivity between conductors and insulators that decreases with increasing temperature. The four-probe method uses four probes in contact with the semiconductor in a straight line to supply current and measure voltage. The resistivity is calculated using the measured voltage, current, probe spacing, and thickness along with a correction factor that depends on thickness and spacing. Temperature dependence of resistivity follows an exponential relationship related to the material's band gap. The four-probe method provides an accurate way to characterize semiconductors and their use in devices like resistance thermometers and induction hardening processes.
1. Electric current is produced when electrons flow through a conducting path from a negatively charged end to a positively charged end.
2. A simple electric circuit consists of a power source, conductor, load, and switch. Current (I) is the rate of flow of electric charge (Q) through a cross-sectional area over time and is measured in amperes.
3. Resistance (R) is a measure of how difficult it is for current to pass through a material and is calculated as the ratio between potential difference (V) and current (I). Resistance depends on the material's length, cross-sectional area, and temperature.
This document discusses key concepts related to electricity including current, potential, electromotive force, internal resistance of cells, resistance of conductors, Ohm's law, resistivity, conductivity, and combinations of resistors. It defines current as the rate of flow of charge and describes how current, potential, resistance, and resistivity are calculated. It also explains how resistance and resistivity change with temperature and the formulas for calculating equivalent resistance when resistors are combined in series or parallel.
This document discusses resistive sensors and their applications. It begins by defining resistive sensors as transducers that convert mechanical changes into electrical signals by changing resistance. Common resistive sensors include potentiometers, strain gauges, thermocouples, photoresistors and thermistors. The document then covers the theory of how resistance changes based on length, area, composition and temperature. It provides examples of specific resistive sensors and their typical applications, such as using light dependent resistors for light switches and strain gauges for sensors in electronic balances. In closing, it discusses how the resistance of sensors varies with changes in factors like temperature, strain or light intensity.
The resistance of a conductor depends on its length, cross-sectional area, and material composition. Resistance increases with length, decreases with area, and varies between materials. Ohm's law states that current is directly proportional to voltage and inversely proportional to resistance. Power dissipated in a resistance is calculated using P=IV, P=I^2R, or P=V^2/R, and causes the resistance to increase in temperature.
There are three types of electrical charges: positive charges consist of protons, negative charges consist of electrons, and the SI unit of charge is the coulomb. Conductors contain free or loosely bound electrons that allow them to conduct electricity, while insulators do not have free electrons and obstruct electricity flow. Potential difference is defined as the work required to move a unit positive charge between two points in an electric field. Common measuring instruments include the voltmeter, which measures potential difference, and the ammeter, which measures electric current in amperes. Resistors can be connected in series, where the total resistance is the sum of individual resistances, or parallel, where the total resistance is lower than the lowest individual resistance.
There are two types of charges: positive charges consist of protons, and negative charges consist of electrons. The standard unit of charge is the coulomb. Conductors contain free or loosely bound electrons that allow them to conduct electricity, while insulators do not have free electrons and obstruct electricity flow. Ohm's law defines the relationship between voltage, current, and resistance in a circuit. Joule's law states that the heat produced is directly proportional to the square of the current, the resistance, and the time of current flow. Electric power is defined as voltage multiplied by current and measured in watts.
based on class 10 chapter electricity.
consists of topic such as-
electric potential,electric current, resistors ,series and parallel connection, heating effect of electric current, electric power,etc.
based on class 10 chapter electricity.
consists of topic such as-
electric potential,electric current, resistors ,series and parallel connection, heating effect of electric current, electric power,etc.
There are two types of charges: positive charges consist of protons, and negative charges consist of electrons. The standard unit of charge is the coulomb. Conductors contain free or loosely bound electrons that allow them to conduct electricity, while insulators do not have free electrons and obstruct electricity flow. Resistance is a measure of the difficulty electrons have in moving through a material. Ohm's law states that current is directly proportional to voltage and inversely proportional to resistance. Joule's law describes how electrical energy is converted to heat energy when a current passes through a resistor.
This document provides an overview of key concepts in electricity including:
1. Electric current is the flow of electrons through a conductor. Current is measured in amperes and flows from positive to negative terminals.
2. An electric circuit is a closed loop that allows current to flow. A circuit includes a power source, conducting wires, and components like light bulbs.
3. Resistance is a material's opposition to current flow. It is measured in ohms and depends on a material's length, cross-sectional area, and resistivity.
This document contains an investigatory physics project on determining the resistivity of different metal wires using Ohm's Law. It includes an introduction to resistance and resistivity, materials used, the procedure followed, observations recorded, calculations of resistivity for each metal, and a conclusion. The resistivity values obtained were 10.5 ×10^-8 Ωm for iron, 2.7×10^-8 Ωm for aluminium, 48.2×10^-8 Ωm for manganese, and 1.7×10^-8 Ωm for copper. The student concluded that Ohm's Law holds true and the relationship between potential drop and current is linear.
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2. Ohm’s Law and Resistance
Ohm’s law states that the voltage or potential
difference between two points is directly proportional
to the current or electricity passing through the
resistance, and directly proportional to the resistance of
the circuit. The formula for Ohm’s law is V=IR. This
relationship between current, voltage, and relationship
was discovered by German scientist Georg Simon Ohm.
Let us learn more about Ohms Law, Resistance, and its
applications.
3.
4. How do we establish the current-voltage relationship?
In order to establish the current-
voltage relationship, the ratio V
/ I remains constant for a given
resistance, therefore a graph
between the potential difference
(V) and the current (I) must be a
straight line.
5. Resistivity
Resistivity (ρ) is a fundamental
property of a material that
quantifies how strongly it resists
the flow of electric current. It is
specific to each material and is an
intrinsic characteristic that
depends on factors such as
temperature and the material's
chemical composition. The
resistivity of a material
determines how much resistance
it will offer to the flow of electric
current.
6. Resistance and Resistivity:
Resistance (R) is a measure of how difficult it is for electric current to
pass through a given object or material. It depends on both the resistivity
of the material and its dimensions. The relationship between resistance,
resistivity, and the physical dimensions of the material is described by the
following formula:
R = ρ * (L / A)
Where: R is the resistance of the material (measured in ohms, Ω), ρ (rho)
is the resistivity of the material (measured in ohm-meters, Ω·m), L is the
length of the material (measured in meters, m), A is the cross-sectional
area of the material (measured in square meters, m²).
From this formula, we can see that resistance is directly proportional to
the resistivity of the material and the length (L) of the material, and
inversely proportional to its cross-sectional area (A). Therefore, materials
with higher resistivity or longer lengths will have higher resistance, while
materials with larger cross-sectional areas will have lower resistance.
7. Conductance:
Where: G is the conductance (measured in siemens, S), R is the
resistance (measured in ohms, Ω).
G = 1 / R
Conductance (G) is the reciprocal of resistance. It is a measure of how easily electric
flow through a material. The concept of conductance is used to quantify the opposite
of resistance, which is the ease of electric flow. The formula for conductance is:
8. Conductivity by Voltage-Current (I-V)
Characteristics
he Voltage-Current (I-V) characteristics describe the relationship between the voltage applied across a
material and the resulting current flowing through it. This relationship is crucial in understanding the
behavior of different materials concerning their electrical conductivity. The I-V curve can provide insights
into how a material responds to changes in voltage and how it conducts electricity.
For different materials, the I-V characteristics can be broadly classified into three types:
1. Ohmic Conductors: Ohmic conductors, also known as linear conductors, exhibit a linear
relationship between voltage and current. In other words, their I-V curves are straight lines passing through
the origin (0, 0) on a graph. The resistance of ohmic conductors remains constant, regardless of the
magnitude of the applied voltage. The conductivity (σ) of an ohmic conductor can be determined by
measuring the slope of its I-V curve:
σ = ΔI / ΔV
Where: σ is the conductivity (measured in siemens per meter, S/m), ΔI is the change in current (measured in
amperes, A), ΔV is the change in voltage (measured in volts, V).
Example: Most metallic conductors like copper, aluminum, and silver exhibit ohmic behavior under normal
operating conditions.
9. 2.Non-Ohmic Conductors: Non-ohmic conductors, also known as
non-linear conductors, do not follow a linear relationship between voltage and current.
The I-V curves for these materials are curved rather than straight lines. The resistance
of non-ohmic conductors varies with the magnitude of the applied voltage. As a result,
the conductivity of non-ohmic conductors cannot be determined directly from a single I-
V curve. Instead, it requires more complex mathematical models or separate
measurements at different voltage levels to assess their conductance accurately.
Example: Semiconductor devices, such as diodes and transistors, are classic examples of
non-ohmic conductors.
3.Insulators: Insulators are materials with extremely high resistivity, resulting in
very low conductivity. In their I-V curves, insulators typically have a flat or nearly flat
region at low applied voltages, indicating that very little current flows through them.
However, when the applied voltage exceeds a certain threshold (known as the
breakdown voltage), the insulator suddenly starts conducting significantly.
Example: Materials like rubber, glass, and plastics act as insulators under normal
conditions.
10. Real-world Examples of Using I-V Characteristics to
Measure Conductivity:
1.Semiconductor Characterization: In semiconductor device testing and manufacturing, I-V
characteristics are used to understand and optimize the performance of electronic
components. By analyzing the I-V curves of transistors and diodes, engineers can determine
important parameters such as the threshold voltage, saturation current, and on/off
characteristics of these devices.
2.Electrical Power Transmission: In power distribution systems, I-V characteristics are
critical for assessing the conductivity of power transmission lines and cables. These curves
help identify resistive losses and ensure efficient power delivery.
3.Battery Testing: I-V curves are used to characterize the behavior of batteries. They provide
valuable information about the battery's internal resistance, capacity, and overall health,
which is essential in battery testing and development.
4.Solar Cell Efficiency: For solar cells, I-V characteristics help evaluate their efficiency and
performance under different lighting conditions. The curves indicate the maximum power
point and efficiency of the solar cell.
In summary, I-V characteristics provide valuable insights into the
electrical conductivity of different materials and devices. By analyzing
these curves, engineers and scientists can optimize electronic
components, assess material behavior, and enhance the efficiency of
various electrical systems.
11. Advantages of 4-Probe over 2-Probe
Technique
Resistance measurements are essential in various fields, such as electronics, materials science, and
electrical engineering. Two common techniques used to measure resistance are the 2-probe
method and the 4-probe method. Let's explore each method and understand their differences, as
well as the limitations of the 2-probe technique and how the 4-probe technique overcomes them.
2-Probe
Method:
In the 2-probe method, a voltage (V) is applied across the
sample, and the resulting current (I) is measured using two
probes. The resistance (R) of the sample is then calculated
using Ohm's law:
R = V / I
The two probes serve both to apply the voltage and to
measure the resulting current. While the 2-probe method is
straightforward and simple to implement, it has limitations
due to the presence of contact resistances.
12. Limitations of the 2-Probe Method (Contact
Resistance):
1. Contact Resistance: The main limitation of the 2-
probe method is the presence of contact resistances
at the points where the probes make contact with the
sample. These contact resistances can be
significant, especially when measuring small or
highly resistive samples. The contact resistances
add to the measured resistance, leading to
inaccurate results and underestimation of the true
resistivity of the sample.
2. Current Shunting: In the 2-probe technique, the
current passes through the same points where the
voltage is applied, leading to potential current
shunting through the contact resistances. This
results in an uneven current distribution through the
13. 4-Probe Method:
The 4-probe method, also known as
the Kelvin method or 4-point probe
method, is a more accurate and
reliable technique for measuring
resistivity, especially in highly resistive
materials or samples with small
dimensions.
It overcomes the limitations of the 2-
probe method by using four separate
probes for voltage application and
current measurement.
14. How the 4-Probe Technique Overcomes
Limitations:
1- Elimination of Contact Resistance: In the 4-probe method, two of the probes are used
for applying a known voltage across the sample, while the other two probes are used for
measuring the resulting current. The current measurement probes are spaced at a fixed
distance, much smaller than the size of the sample. Since the current measurement probes
are separate from the voltage application probes, the contact resistances do not affect the
measurement. The measured current is not distorted by the contact resistances, leading to
accurate resistance measurements.
2- Even Current Distribution: With the 4-probe technique, the current is injected into the
sample through the current application probes and collected by the current measurement
probes, creating a well-defined current path within the sample. This ensures an even
current distribution, eliminating current shunting and providing more accurate resistivity
measurements. The 4-probe technique is commonly used for measuring the resistivity of
various materials, including semiconductors, thin films, and nanomaterials, where accurate
and reliable resistance measurements are crucial. It has found applications in research,
quality control, and materials characterization due to its capability to measure resistivity
independently of contact resistances, making it a powerful tool in the study of electrical
properties of materials.
15. Hall effect
The Hall effect is a fundamental phenomenon in physics that describes
the behavior of charged particles, such as electrons or holes (positively
charged vacancies in semiconductors), when they move through a
magnetic field and an electric current is present. It was first discovered
by the American physicist Edwin Hall in 1879.
16. Relationship to Magnetic Fields:
When a charged particle, carrying an electric current, moves through a magnetic field perpendicular
to the direction of the current, it experiences a force called the Lorentz force. This force acts
perpendicular to both the direction of the current and the magnetic field. As a result, the charged
particles are deflected to one side of the conductor, creating an electric field in the perpendicular
direction to the current flow. This phenomenon is known as the Hall effect.
The Hall effect is based on the principles of electromagnetism and can occur in various conductive
materials, including metals and semiconductors.
17. Hall Effect Setup
and
Measurement of
Charge Carriers'
Mobility and
Concentration:
The Hall effect is typically studied using a setup called the
Hall effect apparatus. It consists of a thin conducting plate
or a semiconductor sample through which a known current
is passed along its length. The plate is placed in a magnetic
field directed perpendicular to the current flow and the
plate's surface. The setup includes voltage probes at the
sides of the plate to measure the Hall voltage.
To measure charge carriers' mobility and concentration in the
material, researchers vary the current, the magnetic field strength, or
both. By measuring the Hall voltage across the sample and knowing
the current and magnetic field values, the following parameters can
be determined:
Hall Coefficient (RH): The Hall coefficient quantifies the
magnitude and direction of the Hall voltage produced by a
unit magnetic field and current density. It is given by:
RH = VH / (B * I)
Where: RH is the Hall coefficient, VH is the Hall voltage, B
is the magnetic field strength, and I is the current passing
through the sample.
18. Applications
of the Hall
Effect:
Determining Material Properties: The Hall effect is commonly used to study the electrical properties of materials, including their carrier concentration, mobility, and type of
charge carriers.
Semiconductor Characterization: In semiconductor devices, the Hall effect is
used to determine the carrier concentration and mobility, providing valuable
information for device design and optimization.
Magnetic Field Sensing: Hall effect sensors are widely used to measure
magnetic fields in applications like compasses, current sensors, and proximity
switches.
Magnetic Imaging: Hall effect sensors can be utilized to create two-dimensional
images of magnetic fields for non-destructive testing and imaging applications.
Hall Effect Thrusters: In space propulsion systems, Hall effect thrusters utilize
the Hall effect to produce thrust by ionizing a propellant gas and accelerating
the ions using magnetic fields.
Current Measurement: The Hall effect is employed in current sensing
applications, especially in electronic circuits and power systems.
19. Capacitance-Voltage
(CV) Characteristics
Capacitance is a fundamental property
of electronic components that
measures their ability to store an
electric charge when a voltage is
applied to them. It is an essential
parameter in electronic devices and
plays a crucial role in various
applications.
Capacitance (C) is defined as the ratio
of the electric charge (Q) stored on a
component's plates to the voltage (V)
applied across the component:
C = Q / V
The unit of capacitance is the farad (F),
where 1 farad is equal to 1 coulomb per
volt. However, in practical electronic
devices, capacitance is often measured
in microfarads (µF) or picofarads (pF)
due to their small sizes.
Capacitors are electronic components designed to store and
release electric charge. They consist of two conductive plates
separated by an insulating material called a dielectric. When a
voltage is applied across the capacitor, electrons accumulate on
one plate while an equal number of electrons are drawn from the
other plate. The capacitance value determines the amount of
charge the capacitor can store for a given voltage.
20. Capacitance-Voltage (CV) characteristics
1
Experimental Setup:
Set up the
semiconductor device
for measurement. This
may involve placing
the device in a test
fixture or mounting it
on a probe station.
Ensure that the
connections are made
correctly to apply the
desired voltage to the
device and measure
its capacitance.
2
Biasing the Device:
Apply a small DC bias
voltage (usually in
reverse bias for diodes
or in sub-threshold
region for MOSFETs)
to the device to
establish a starting
point for the CV
measurement.
3
Applying AC Signal:
Superimpose a small
AC signal on top of
the DC bias voltage.
The AC signal's
frequency is typically
in the range of a few
kHz to MHz,
depending on the
device and the
measurement
requirements.
4
Measuring
Capacitance: Measure
the current flowing
through the
semiconductor device
due to the AC signal
using a current-
sensitive
measurement
instrument, such as a
lock-in amplifier or an
impedance analyzer.
Simultaneously
measure the voltage
applied to the device
using a voltage
measurement
instrument.
5
Varying Voltage:
Slowly vary the DC
bias voltage while
keeping the AC signal
constant. Start from
the initial bias point
and move towards the
desired voltage range
for the measurement.
6
Plotting the Data:
Record the current
and voltage data for
each bias point. Plot
the measured current
(or capacitance) as a
function of the
applied voltage
To obtain Capacitance-Voltage (CV) characteristics and interpret them, you typically perform a
measurement on a semiconductor device, such as a diode or a MOSFET, while varying the
voltage applied to the device. The CV characteristics provide valuable insights into the
behavior and properties of the semiconductor device. Here's a step-by-step explanation of the
process:
21. Interpretation of CV
Characteristics:
Capacitance-Voltage Plot:
• The resulting plot is called the CV curve or CV
characteristic.
• The x-axis represents the applied voltage, and the y-axis
represents the measured capacitance (or current).
• Capacitance is inversely proportional to the width of the
depletion region in the semiconductor device. As the bias
voltage changes, the depletion region width changes,
affecting the capacitance.
Analysis for Diodes:
• For diodes, the CV curve shows the abrupt transition
from the reverse-biased to the forward-biased region.
• The capacitance is relatively constant in the reverse-
biased region, while it drops sharply in the forward-
biased region due to the reduction in the depletion
region width.
22. applications of CV characteristics in semiconductor
device characterization:
1. Threshold Voltage Determination (MOSFETs):
• CV measurements are commonly used to determine the threshold voltage (Vth) of Metal-Oxide-
Semiconductor Field-Effect Transistors (MOSFETs).
• The threshold voltage represents the point at which the MOSFET switches from the off-state to the on-
state.
• Knowing Vth is essential for proper circuit design and optimization, as it affects the MOSFET's behavior
in different operating regions.
2. Capacitance and Doping Concentration Estimation:
• CV measurements are used to determine the capacitance of the depletion region in semiconductor
devices.
• By analyzing the capacitance values at different bias voltages, researchers can estimate the doping
concentration in the semiconductor material.
• This information is critical for understanding device performance and optimizing the doping profile to
achieve specific electrical characteristics.
23. Cont..
3. Interface State Density Measurement:
• Interface state density refers to the number of charge traps present at the
semiconductor-insulator interface in MOSFETs.
• CV measurements can be used to extract information about interface state density,
which directly impacts device performance, such as leakage currents and subthreshold
behavior.
• Characterizing and reducing interface state density is crucial for enhancing device
performance and reliability.
3. Oxide Thickness and Quality Assessment:
• For MOSFETs and other devices with an oxide layer, CV measurements can provide
insights into the oxide thickness and quality.
• Changes in capacitance with different bias voltages can reveal variations in the oxide
layer's thickness, which is essential for ensuring consistent device performance.
3. Barrier Height Determination (Schottky Diodes):
• CV measurements are widely used to determine the barrier height in Schottky diodes,
which are metal-semiconductor junctions.
• The barrier height affects the diode's rectifying properties and is essential for optimizing
diode performance in various applications.
24. Cont..
6. Mobility Extraction (MOSFETs and Bipolar Transistors):
• CV measurements, along with other electrical characterization techniques,
are used to extract carrier mobility in both MOSFETs and bipolar
transistors.
• Understanding carrier mobility is crucial for designing high-speed and low-
power devices.
6. Quality Control and Process Monitoring:
• CV measurements are valuable tools for quality control and process
monitoring during semiconductor device fabrication.
• By comparing measured CV characteristics to expected values,
manufacturers can detect process variations and identify potential issues
in the production line.
6. Device Modeling and Simulation:
• The data obtained from CV measurements are used in device modeling
and simulations to accurately predict device behavior under different
conditions.
• Device models are essential for circuit designers to optimize circuit
performance and analyze complex circuits.