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Electricity
Electricity
Everything in the world is made up of atoms.
Each atom has smaller parts in it. One of
those parts is called electrons. Electrons
can move from atom to atom. When an
electron moves to a different atom, it causes
another electron to have to move. When
electrons move quickly from one atom to
another is it called Electricity!
Inside an atom,
electrons have a
negative charge
and protons have
a positive
A charge is a
charge. These
measure of the
particles attract
extra positive or
negative particles
each other.
that an object has.
Electricity occurs in
2 different forms
Static
• Is stationary
E.g. Brush your hair
Wool socks in
tumble drier
Current
• Flows around circuit
E.g. turn on light
Walkman
Static Electricity
Static electricity is
the charge that
stays on an object.
Unlike charges
attract each other,
and like charges
repel each other.
The steady flow of
electricity is
called an
electric current.
A current will
move along a
wire or a path
called a circuit.
Circuit means to
“go around.”
Any circuit which is not complete is considered
an open circuit. A complete circuit which is not
performing any actual work can still be a closed
circuit. For example, a circuit connected to a
dead battery may not perform any work, but it is
still a closed circuit.
A circuit is considered to be closed when
electricity flows from an energy source to the
desired endpoint of the circuit. The open status
of the circuit doesn't depend on how it became
unclosed, so circuits which are manually
disconnected and circuits which have blown
fuses, faulty wiring or missing components are
all considered open circuits.
Open circuit
Closed circuit
Circuits
•A series
circuit is a
circuit that
has only one
path for the
current.
•A parallel
circuit has
more than
one path for
current to
travel.
SERIES CIRCUIT
• Has a single loop for
electrons to travel
round
• Components are
connected one after
another
• Current has to travel
through all components
• Current is the same at
all points
• Voltage is shared
between components
PARALLEL CIRCUIT
• Has two or more paths
for electrons to flow
down
• Current is shared
between the branches
• Sum of the current in
each branch = total
current
• Voltage loss is the same
across all components
SUMMARY
In Series
Current
Always the same
Voltage
Voltage from source =
voltage used
Voltage is shared
between power users
In Parallel
The branches share
electrons and add to the total
Voltage is the same in all
branches
•Lights in our
homes are
wired in
parallel
circuits.
ELECTRICITY
• Electricity is forced around a circuit
by an electrical force field
• Flow of electricity around a circuit is
called CURRENT
• Current measured in amps
• Voltage – Increase or decrease in
the amount of electrical energy
carried by the current.
CURRENT
Current is the flow of electrons
around a circuit
•DC = direct current like battery
•Electrons flow in one direction
•AC = Alternating current like mains
•Electron flow changes direction 50x
per second
Definition of AC
•AC stands for "alternating current." The polarity of the
electric charge switches from positive to negative, or
alternates, at a fixed rate. For typical household current
in the United States, the alternation rate is 60 cycles per
second.
Definition of DC
•DC stands for "direct current." The polarity of the electric
charge does not switch back and forth. This is why one end
of a battery is positive, and the other end is negative.
Current flows from the negative end of the battery, through
the device being operated and back to the battery at the
positive end.
VOLTAGE
Gain or loss of energy as it
passes through a component
•Voltage lost = voltage gained
•In series voltage loss is shared between
components
•In parallel voltage loss is the same across
all components
Conductor
•A conductor
is a material
that current
can pass
through
easily, like
metals.
Resistor
•A resistor is a material that
resists, but doesn’t stop the
flow of current.
Insulator
•An insulator is a
material that
current cannot
pass through
easily, like plastic.
Electric Cell
•An electric cell
supplies
energy to move
charges
through a
circuit, like a
battery.