Transcript Electronics - ozscienceresources

In 1771, Luigi Galvani
discovered that the
muscles of dead frogs
twitched when struck
by a spark
 May have inspired the
idea behind the story
Frankenstein
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Generation of Electricity = [Coil of Wire] + [Magnetism] + [Relative Motion]

The basic components are:
1.
Power Plant: Electricity is produced
2.
Power Grid: A network that
3.
Transmission Substation:
4.
Distribution Substation:
here
connects power plants to substations
and substation to homes.
Transformers increase voltage so that
volts can be sent over long distances.
5.
Transformers reduce voltage to a level
suitable for the surrounding community
Distribution System: Delivers
electricity to homes and businesses.
Line may be a underground or
overhead.
6.
Service Connection: Connection
of customers to the grid. A meter is
connected also to measure the
amount of electricity used by
customers
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When you switch something on, you complete a pathway for
electricity to flow through.
The pathway that allows electrical energy to flow is called an
electric circuit.
Electric circuits consist of three components:
 A Power Supply: Provides electrical energy
 A Load: Converts electrical energy into another form
 A Conducting Path: Allows electric charge to flow around
the circuit.
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Electric circuits consist of three components:
 A Power Supply: Provides electrical energy
 A Load: Converts electrical energy into another form
 A Conducting Path: Allows electric charge to flow around
the circuit.
Power Supply
Load
Conducting Path
=
=
=
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Current measures the amount of charge
flowing through a circuit .
A large current has more charge flowing
every second than a small current.
Current is measured in a unit
called ampere (A) or ‘amps’
 Milliamps (mA) are used to
measure small currents.
 Current can be measured
using a device called an
ammeter.
 Ammeter’s need to be
inserted into the circuit to get
a reading.

Voltage is measure in
Volts (V)
 A device that measures
the amount of volts
passing through a
circuit is called a
voltmeter
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Voltage is a measure of the amount of energy
there is to push charge through a circuit.
Voltage is supplied by batteries, power packs
and power points.
Batteries, power packs
or power points are all
considered energy
sources.
 They provide all the
electric energy and
voltage to a circuit.
 Energy sources create
an electric field that
pushes electrons
around a circuit.

Power points supply
approximately 240
volts into your home
 Power packs like the
ones we use in class
supply up to 12 volts
 The power for which is
produced in a variety of
power plants.
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Batteries are used
when we need portable
energy sources.
1 AA battery provides
1.5 volts
While car batteries
provide 12 volts
Batteries are made up
of cells.
These cells can be
either wet or dry.
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In this wet cell, zinc
reacts with the acid and
releases electrons.
If a circuit is connected to
the plates then the
electrons will flow to the
copper plate
As they flow through the
circuit the globe will
light.
Wet cells are usually
large and heavy and can
leak acid if tipped over.
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A car battery is a
collection of wet cells.
The wet substance is
sulfuric acid
The plates are made of
lead and lead oxide.
While a car is running it
reverses the chemical
reaction recharging the
battery.
Eventually chemicals
build up on the plate and
the batter “dies”.
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=
4.5 volts
Being large and heavy wet cells
are useless for small devices like:
▪ Ipods
▪ Laptops
▪ Remotes
They use small portable cells
called dry cells.
Dry cells contain a chemical
paste and their electrodes are
designed to save space.
It is common that several
batteries are connected
together to supply more voltage.
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A photovoltaic cell (or
solar )is made up of two
layers.
These two layers are
semiconductors.
When sunlight strikes the
top layer electrons are
given energy to move to
the bottom layer.
This creates an electric
current.
Aka the electric eel
Actually a freshwater
fish.
 It can produce up to
600 volts
 This is five times the
amount found in an
electrical outlet
 Uses the electric field
to stun fish and to see
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electrolocation
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http://wsc.pv.unsw.edu
.au/
This website allows you
to build and name a
virtual solar powered
car
 You are then able to
race it against
computer generated
cars.

The important feature
of this game is the
design process.
 You have a limited
budget of $240,000 to
build your car.
 You need to decide on
what balance of
components are
important for speed
and power.
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A conductor is a substance that allows current
to flow through it easily.
Examples are metals like:
▪ Copper: used commonly in electric circuits
▪ Aluminium: More expensive, used when copper is unsuitable.
Materials that do not
allow current to pass
through them are
called Insulators.
 Examples of insulators:

▪ Plastic
▪ Rubber
Brief research assignment.
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What are
superconductors ?
What uses are there for
superconductors?
Briefly describe how they
work.
Useful links:
 http://superconductors.org/IN
dex.htm
 http://science.howstuffworks.
com/question610.htm
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All metals conduct electricity, but some do so
better than others.
Tungsten and nichrome for example are not
very good at conducting electricity.
Therefore electricity flows easier in copper
wires than in tungsten.
This is called resistance.
Resistance converts
electrical energy into
heat and light.
 This is used in light
globes with tungsten
filaments.
 Conductors have a low
resistance
 Insulators have a high
resistance
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Without any resistance
(such as a globe or
heating element) too
much current can flow
through a circuit.
This may generate too
much heat in connecting
wires or the energy
source.
This might damage the
circuit causing it to melt
or catch fire!
This is known as a Short
Circuit
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If two globes are arranged in a single line then they are
said to be in series.
Although the current is said to each globe is the same,
the voltage is shared between the two.
This means that the globes will both glow more dimly.
If one of the bulbs is removed or ‘blows’ then the other
globes in the circuit will not light up.
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If two globes are arranged in separate branches of a circuit
then the are said to be in parallel.
Each globe has the same amount of energy and voltage
supplied to them .
The current is divided between them,
This means that they will glow with the same ‘brightness’
Also if one globe is removed from this circuit the other will
still remain lit.
SERIES
A series circuit arranged of 20 lights
would share 240 volts from a power point.
Therefore each globe receives 12 volts.
Disadvantages:
• If one globes broke then all the other
globes with also go out
• This would make it difficult to find the
bad globe.
PARALLEL
In a parallel circuit all lights are powered
by a low voltage source. A transformer
reduces the voltage from 240 volts to 12
volts. All globes receive 12 volts.
Advantages:
• If one globes breaks all the other globes
still have power.
• This makes it easier to find the broken
globe.
Type of Circuit
Series
Parallel
Voltage
Current
Split
Normal
Normal
Split
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Circuits can be combinations of series and parallel sections.
Current will always take the easiest way through a circuit.
A section with a single globe will be easier to travel on than a
section with two.
Also it will carry twice as much current.
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Electrical wiring within you house is one big parallel
circuit
Electrical companies supply 240 volts to your house.
Each power point creates an extra parallel section that
receives the same 240 volts.
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Direct Current (DC)
 When the current flows in
only one direction.
 An example of this is a
battery.
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Alternating Current
(AC)
 Current flows backwards
and forwards.
 Energy is supplied to
houses like this because it
is easier to generate and
transmit.
What is wrong with this picture?
What's wrong here?
Short circuits occur when an easier path for current is created.
A huge current flows through causing the circuit to overheat
and melt.
 You could even become part of the circuit and be shocked or
electrocuted!
 To prevent this home circuits have fuses or circuit breakers.
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A fuse is a thin metal wire,
that breaks when too much
current passes through it.
 Fuses are rated according to
the amount of current that
causes them to melt.
 Therefore a 5 amp fuse will
melt at a current of 5 or more
amps.
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Fuses used to be the most
common method for
protecting circuits within a
house.
 These days new houses are
built with circuit breakers
instead.
 Circuit breakers are special
switches that ‘trip’ (turn off)
the circuit if too much
current flows through.
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Electric shock and
electrocution (death by
electricity) will occur if current
finds a path through the body.
 Only a small current can
cause death.
 The current damages your
tissues and interferes with the
electric signals that drive the
heart and the brain.
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Step 1: Climb electrical
pole.
Step 2: Reach out and
touch high voltage
conductor.
Step 3: 16,000 volt Human
fireball!
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If you find someone who has
collapsed from an electric
shock:
 Call OOO
 Switch off main power (if possible)
 Do not touch the person
(otherwise you will get shocked)
 You may be able to move the
person if you use an insulating
material (plastic rope, garden
hose)
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The electric chair was invented to
replace hanging as a method of
execution.
It was intended to be a quick and
painless alternative
In the first ever electric chair
execution 1000 volts were applied.
This burnt skin and burst blood vessels
It still took another 70 seconds at 1300
volts to kill the prisoner.
Other prisoners convulsed so violently
they broke their own arms and legs.
So really its not all that quick and
painless !
Tour Guide Robot - Toyota
Geminoid HI-1 -Hiroshi Ishiguro
Asimo - Honda
ASIMO stands for Advanced
Step in Innovative Mobility
 ASIMO is a humanoid robot
created by Honda motor
company.
 Height: 130 cm Weight: 54 Kg
 By the end of 2007 there were
only 46 ASIMO robots in
existence.
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Further Information:
http://world.honda.com/ASIMO
/
• ASIMO has been in the making for 20 years
• In the picture above you can see the current ASIMO compared
to its previous versions
Geminoid HI-1is a robotic
replica of Professor Hiroshi
Ishiguro.
 Professor Ishiguro can
operate Geminoid from a
distance.
 This allows him to give two
lectures simultaneously at
universities that are Km’s
apart.
 Further Resources:
 http://www.irc.atr.jp/Gemi
noid/overview.html
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Research a REAL robot
Create a presentation for
the entire class
The selection of the robot
is up to you
The form of the
presentation is also up to
you
Or make a Timeline of
Robot development
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Individually you are to
design a robot to fulfil a
specific function.
You must include a design
of your robot with labelling
to explain why each section
is essential to its function.
You must also create a
short comic strip that
demonstrates your robot in
action.