Basic Electrical Quantities
The basic electrical quantities are electrical current and voltage, electrical charge, resistance,
capacitance, inductance and electric power.
Charge
Definition
➢ property that will cause objects to attract or repel one another.
➢ is a characteristic of a unit of matter that expresses the extent to which it has more or fewer
electrons than protons.
➢ The electric charge is denoted by symbol Q or q and measured in Coulombs (C).
There are three types of electric charges - positive, negative and neutral.
Electron _negatively charged particle orbiting the nucleus of all atoms.
A proton, positively charged particle in the nucleus of all atoms. A neutron, atomic particle having no
charge located in the nucleus of an atom.
One coulomb is the quantity of charge transferred in one second.”
Q = I.t
Question
A current of 2A is drawn by the filament of an electric bulb for 10 minutes. Find the amount of electric
charge that flows through the circuit.
Sol:
Given, I= 2 A, t=10 minutes=10x60= 600 s
Q = I× t = 2 × 600=1200C
Current
➢ It is the rate of flow of charge in a circuit/is the movement of charges in a conductor.
➢ Electric Current is the rate of flow of electrons in a conductor.
➢ Symbol for current is I.
, ➢ The SI Unit of electric current is the Ampere.Ampere is defined as the unit of electric current
that is equal to the flow of one Coulomb per second.
➢
Conventional Current flow Vs Electron Flow
conventional current flow
The conventional current flow is from the positive to the negative terminal and indicates the direction in
which positive charges would flow
Electron flow
The electron flow is from negative to positive terminal. Electrons are negatively charged and are
therefore attracted to the positive terminal as unlike charges attract.
Types of Electric current
There are two types of electric current known as alternating current (AC) and direct current (DC).
• Direct Current − A direct current (DC) is one which flow in only one direction.
• Alternating Current − An alternating current (AC) is one whose magnitude changes continuously
and direction changes periodically.
Electric current and circuit diagram elements
The basic electrical quantities are electrical current and voltage, electrical charge, resistance,
capacitance, inductance and electric power.
Charge
Definition
➢ property that will cause objects to attract or repel one another.
➢ is a characteristic of a unit of matter that expresses the extent to which it has more or fewer
electrons than protons.
➢ The electric charge is denoted by symbol Q or q and measured in Coulombs (C).
There are three types of electric charges - positive, negative and neutral.
Electron _negatively charged particle orbiting the nucleus of all atoms.
A proton, positively charged particle in the nucleus of all atoms. A neutron, atomic particle having no
charge located in the nucleus of an atom.
One coulomb is the quantity of charge transferred in one second.”
Q = I.t
Question
A current of 2A is drawn by the filament of an electric bulb for 10 minutes. Find the amount of electric
charge that flows through the circuit.
Sol:
Given, I= 2 A, t=10 minutes=10x60= 600 s
Q = I× t = 2 × 600=1200C
Current
➢ It is the rate of flow of charge in a circuit/is the movement of charges in a conductor.
➢ Electric Current is the rate of flow of electrons in a conductor.
➢ Symbol for current is I.
, ➢ The SI Unit of electric current is the Ampere.Ampere is defined as the unit of electric current
that is equal to the flow of one Coulomb per second.
➢
Conventional Current flow Vs Electron Flow
conventional current flow
The conventional current flow is from the positive to the negative terminal and indicates the direction in
which positive charges would flow
Electron flow
The electron flow is from negative to positive terminal. Electrons are negatively charged and are
therefore attracted to the positive terminal as unlike charges attract.
Types of Electric current
There are two types of electric current known as alternating current (AC) and direct current (DC).
• Direct Current − A direct current (DC) is one which flow in only one direction.
• Alternating Current − An alternating current (AC) is one whose magnitude changes continuously
and direction changes periodically.
Electric current and circuit diagram elements
