Transcript document

Chapter 19
Using Electricity ‘wakakakaka’
Power
• Power of an electrical component is
equals to energy converted divided by
time hence making it work.
• The S.I.unit for power is watt(w). When the
rate of energy converted is one joule per
second which is quite a tickle to your
finger with a wire to it making it a closed
circuit…The power is said to be one watt.
Reducing Wastage of Electricity…
That’s what people are doing now.
• Due to Singapore’s small geographical size, we
do not have many natural energy thingies such
as fossil fuels or ‘stuff that make electricity other
than it’. The eletrical energy we require is
generated from imported fuels.
• There’re a lot of people who try to ‘subsitude’
fuel by using corn or degradable or even in the
future… FRESH OIL from BIO-Degradable items
such as ‘complete’ amounts of animals ;not only
the fat but bones and the guts too.
Reduce, Reuse, Recycle much?
• Hence it’s very important for us to minimise
SUFFICENT amount of ‘wastage’ of electricity as
the weather now is really hot and my textbook
says minimise electricity = NO Ac. However, it is
also very important for us to save electricity.
• By trying to recycle we have to have factories to
recycle them. Factories that produce smoke to
‘recycle’ something that saves the earth and
pollutes it. How fantastic is the world.
Fossil fuels?
• Fossil fuel is used to generate electricity in
Singapore. Fossil fuel reserves around the
world, however, are getting depleted at a
break-neck-pace due to overwhelming
demand.
• Hence this is what I SAY...
We
have to play a part by using energy
efficient electrical appliances and just go
to the library when your ‘too warm’ to cool.
NO MORE SCHOOL! Just joking…
Understanding Household
Electricity
• A short circuit can accidentaly burn your
school’s test paper in the staff room. It’s
dangerous to put the test papers outside
the printing area in the staff room as there
are short circuits in buildings.
Our
homes and classrooms have many circuits
hidden behind the wall that are intricately
connected. In order for them to function
perfectly, they have to be in a good
condition. (Intricately = complicate - ly
*stares at teaches* >.>
Household wiring
DANGER CLOSE!
• Everyone uses electrical wiring.
• The earth wire is usually yellow but sometimes
green. It's at zero voltage. Usually, no current
flows in this wire. It is connected to the ground.
• The neutral wire is always blue and at zero
voltage. It’s kept at zero by earthing
• The live wire is always brown at a high voltage
of 240V~~. The amount of voltage can be
differed in other countries. (DANGER CLOSE)
Hazards of Electricity-Electrocution
• Electrocution occurs when a person is
injured or killed by a large current passing
through the body. This can happen if the
insulation of wires has been damaged or if
the earth wire of an appliance is not
properly connected. When a person
touches the exposed live wires that are at
a constant 240V. The current flows
through you and ‘kazam’… you die
Electrical Fires
• A short circuit is caused when the live wire
touch the neutral wire. Providing a shorter
path of low resistance for the current to
flow through.
• The large current flowing through the wires
may cause it to over heat and cause a fire.
• Overloading a output socket can overheat
and cause a fire too.
Safety Precautions in using
Electricity :O
• Safety by earthing- When an electric fault
occurs like a short circuit, the earth wire
will carry the current safely to the ground.
Iif there is no earth wire, the current might
flow through someone and kill him or her
or IT OR flow through the furniture or Test
papers in school and start a fire. *yay*
Safety in fuses
• A fuse is a short thin wire placed within an
insulating capsule. The thing wire will melt
when a unexpected large HUGE
GIGANTIC current flows through it. In this
way the circuit will be broken quickly
before the on-coming heat generates
enough heat-ness to burn the equipment.
Safety with circuit BREAKERS
• Best Weapon of all. A circuit breaker is a
type of switch. It’s usually turned on to
allow a current to flow but when the
current in the circuit becomes too large. A
trigger mechanism switches it off and
breaks the circuit. This shuts off the large
current before it can cause any serious
damage or start a fire. <3
FINALLY FINALE!
• For more information on Eletrical Safety
rules.. Refer to text book page 56 to 60.
• Danger’s Close Everywhere.
• Officially done By me.. The leader.
Wallace Chan 2n3
• Classmate who ‘helped’ Joel Lam 2n3