- Electric current is the flow of electric charge.
- It is caused by the movement of electrons or ions.
- Electric current is measured in amperes (A).
Flow of Current in an Electrolyte
- In an electrolyte, current is carried by the movement of ions.
- Ions are atoms or groups of atoms that have an electric charge.
- Positive ions (cations) move towards the negative terminal of the battery.
- Negative ions (anions) move towards the positive terminal of the battery.
- This movement of ions constitutes the flow of electric current.
Flow of Current in an Insulator
- In an insulator, electric current does not easily flow.
- Insulators have tightly bound electrons that are not free to move.
- These materials have a high resistance to the flow of electric current.
- Examples of insulators include rubber, wood, and plastic.
Flow of Current in Semiconductors
- In semiconductors, current is carried by both electrons and holes.
- Semiconductors are materials whose conductivity is between that of insulators and conductors.
- At low temperatures, the majority of charge carriers are holes.
- At higher temperatures, the majority of charge carriers are electrons.
- Semiconductors find applications in diodes, transistors, and integrated circuits.
- In a metal, current is carried by free electrons.
- Metals have loosely bound valence electrons that are free to move.
- These materials have a low resistance to the flow of electric current.
- Metals are commonly used as conductors in electrical circuits.
- Examples of metals include copper, aluminum, and silver.
Electric Current and Current Density - Calculation and Measurement
- Electric current can be calculated using Ohm’s Law: I = V/R.
- I represents the current in amperes (A).
- V represents the voltage in volts (V).
- R represents the resistance in ohms (Ω).
Calculation of Current Density
- Current density (J) is the amount of current flowing per unit area.
- It is calculated using the formula: J = I/A.
- J represents the current density in amperes per square meter (A/m²).
- I represents the current in amperes (A).
- A represents the cross-sectional area in square meters (m²).
Measurement of Current
- Current can be measured using an ammeter.
- An ammeter is connected in series in the circuit.
- It measures the flow of electric charges through the circuit.
- Ammeters have a very low resistance to prevent voltage drop.
Measurement of Current Density
- Current density can be measured using a current density meter.
- A current density meter is a specialized device for this purpose.
- It measures the current passing through a specific area.
- The device usually consists of an ammeter and a calibrated area.
- Calculate the current flowing through a circuit with a resistance of 10 Ω and a voltage of 5 V.
- A wire has a resistance of 2 Ω and carries a current of 4 A. Calculate the voltage across the wire.
- A circuit has a current of 8 A flowing through a 2 m² cross-sectional area. Calculate the current density.
Electric Current and Current Density - Factors Affecting the Flow of Current
- Several factors affect the flow of electric current.
- These include the voltage, resistance, and length of the conductor.
- The type of material and its temperature also play a role.
- Understanding these factors is essential for analyzing electrical circuits.
- Electric current is the flow of electric charge.
- It is caused by the movement of electrons or ions.
- Electric current is measured in amperes (A).
Flow of Current in an Electrolyte
- In an electrolyte, current is carried by the movement of ions.
- Ions are atoms or groups of atoms that have an electric charge.
- Positive ions (cations) move towards the negative terminal of the battery.
- Negative ions (anions) move towards the positive terminal of the battery.
- This movement of ions constitutes the flow of electric current.
Flow of Current in an Insulator
- In an insulator, electric current does not easily flow.
- Insulators have tightly bound electrons that are not free to move.
- These materials have a high resistance to the flow of electric current.
- Examples of insulators include rubber, wood, and plastic.
Flow of Current in Semiconductors
- In semiconductors, current is carried by both electrons and holes.
- Semiconductors are materials whose conductivity is between that of insulators and conductors.
- At low temperatures, the majority of charge carriers are holes.
- At higher temperatures, the majority of charge carriers are electrons.
- Semiconductors find applications in diodes, transistors, and integrated circuits.
- In a metal, current is carried by free electrons.
- Metals have loosely bound valence electrons that are free to move.
- These materials have a low resistance to the flow of electric current.
- Metals are commonly used as conductors in electrical circuits.
- Examples of metals include copper, aluminum, and silver.
Electric Current and Current Density - Calculation and Measurement
- Electric current can be calculated using Ohm’s Law: I = V/R.
- I represents the current in amperes (A).
- V represents the voltage in volts (V).
- R represents the resistance in ohms (Ω).
Calculation of Current Density
- Current density (J) is the amount of current flowing per unit area.
- It is calculated using the formula: J = I/A.
- J represents the current density in amperes per square meter (A/m²).
- I represents the current in amperes (A).
- A represents the cross-sectional area in square meters (m²).
Measurement of Current
- Current can be measured using an ammeter.
- An ammeter is connected in series in the circuit.
- It measures the flow of electric charges through the circuit.
- Ammeters have a very low resistance to prevent voltage drop.
Measurement of Current Density
- Current density can be measured using a current density meter.
- A current density meter is a specialized device for this purpose.
- It measures the current passing through a specific area.
- The device usually consists of an ammeter and a calibrated area.
- Calculate the current flowing through a circuit with a resistance of 10 Ω and a voltage of 5 V.
- A wire has a resistance of 2 Ω and carries a current of 4 A. Calculate the voltage across the wire.
- A circuit has a current of 8 A flowing through a 2 m² cross-sectional area. Calculate the current density.
Slide 21
Electric Current And Current Density - Flow of Current (Electrolyte, Insulator, Semiconductors, Metal)
- Electric current is the flow of electric charge.
- It is caused by the movement of electrons or ions.
- Electric current is measured in amperes (A).
Slide 22
Flow of Current in an Electrolyte
- In an electrolyte, current is carried by the movement of ions.
- Ions are atoms or groups of atoms that have an electric charge.
- Positive ions (cations) move towards the negative terminal of the battery.
- Negative ions (anions) move towards the positive terminal of the battery.
- This movement of ions constitutes the flow of electric current.
Slide 23
Flow of Current in an Insulator
- In an insulator, electric current does not easily flow.
- Insulators have tightly bound electrons that are not free to move.
- These materials have a high resistance to the flow of electric current.
- Examples of insulators include rubber, wood, and plastic.
Slide 24
Flow of Current in Semiconductors
- In semiconductors, current is carried by both electrons and holes.
- Semiconductors are materials whose conductivity is between that of insulators and conductors.
- At low temperatures, the majority of charge carriers are holes.
- At higher temperatures, the majority of charge carriers are electrons.
- Semiconductors find applications in diodes, transistors, and integrated circuits.
Slide 25
Flow of Current in a Metal
- In a metal, current is carried by free electrons.
- Metals have loosely bound valence electrons that are free to move.
- These materials have a low resistance to the flow of electric current.
- Metals are commonly used as conductors in electrical circuits.
- Examples of metals include copper, aluminum, and silver.
Slide 26
Electric Current and Current Density - Calculation and Measurement
- Electric current can be calculated using Ohm’s Law: I = V/R.
- I represents the current in amperes (A).
- V represents the voltage in volts (V).
- R represents the resistance in ohms (Ω).
Slide 27
Calculation of Current Density
- Current density (J) is the amount of current flowing per unit area.
- It is calculated using the formula: J = I/A.
- J represents the current density in amperes per square meter (A/m²).
- I represents the current in amperes (A).
- A represents the cross-sectional area in square meters (m²).
Slide 28
Measurement of Current
- Current can be measured using an ammeter.
- An ammeter is connected in series in the circuit.
- It measures the flow of electric charges through the circuit.
- Ammeters have a very low resistance to prevent voltage drop.
Slide 29
Measurement of Current Density
- Current density can be measured using a current density meter.
- A current density meter is a specialized device for this purpose.
- It measures the current passing through a specific area.
- The device usually consists of an ammeter and a calibrated area.
Slide 30
Example Problems
- Calculate the current flowing through a circuit with a resistance of 10 Ω and a voltage of 5 V.
- A wire has a resistance of 2 Ω and carries a current of 4 A. Calculate the voltage across the wire.
- A circuit has a current of 8 A flowing through a 2 m² cross-sectional area. Calculate the current density.