February 26, 2009 DRILL U3e-L1 It uses direct current because it is powered by a battery. If it used...
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Transcript of February 26, 2009 DRILL U3e-L1 It uses direct current because it is powered by a battery. If it used...
February 26, 2009DRILL
U3e-L1
It uses direct current because it is powered by a battery. If
it used alternating current you would be able to plug
it into a wall outlet. We will find out more about
AC and DC current in this unit.
•Write the question and circle the answer you think is
correct . Next, write why?
What kind of power source do you think provides the proper
current for this shaver to work?
A) AC (Alternating Current)
B) DC (Direct Current)
UNIT 3 – Engineering Design
Engineering, the systematic application of mathematical, scientific, and technical principles, produces tangible end products that meet our needs and desires.
BIG IDEABIG IDEA
U3e-L1
U3e-L1
UNIT 3 – Engineering Design
a. Getting familiar with the Big Idea
b. The Design Process
c. Core Technologies
d. Mechanical Technology
e. Electrical Technologyf. Reverse Technology
g. Fluid Technology
h. Thermal Technology
i. Optical Technology
j. Materials Technology
SUB-UNITSSUB-UNITS
Electrical Technology
PURPOSE OF SUB-UNIT
• To familiarize students with the functioning and applications of electrical technology systems by having you analyze the functioning of electrical systems in terms of their:– common components, – basic system design, – safety considerations, and – simple controls. U3e-L1
Electrical Technology
What is technology?
The application of knowledge, tools, and skills to solve problems and extend human capabilities.
What is a technology system?
A Technology System is a group of subsystems working together to solve problems and extend human capabilities.
U3e-L1
• There are several engineering resources (core technologies) that are the “building blocks” of all technology systems.
• We could store the core technologies on shelves • We can go to those shelves and use technologies
according to our needs in problem solving.
Imagine:Imagine:
Electrical Technology
Core Technologies
Mechanical
Structural Electrical
Electronic Thermal
Fluid Optical
Bio-Tech MaterialU3e-L1
U3e-L1
• A technology system is a group of resources (subsystems) working together to solve problems and extend human capabilities.
– What subsystems make up this system?
• Identify the problem that the technology system solves.
• Speculate on how the device assists people in solving a problem or extending human capability.
What is this technology system?
Definition:
The technology of using small amounts of electricity for controlling, detecting, collecting, storing, retrieving and processing information.
Applications:
Thermostat, metal detector,video recorder, computer,calculator, telephone,television, radio, pace maker, digital watch.
Electronic TechnologyElectronic Technology
U3e-L1
Definition:
The technology of producing, storing, controlling,transmitting and getting work from electrical energy.
Applications:
Power plant generator, flashlight, electric motor in a can opener, doorbell, electric heater, hair dryer.
Electrical TechnologyElectrical Technology
U3e-L1
U3e-L1
Electrical Technology
• Electricity completely surrounds us.• For most of us, modern life would be impossible
without it.• Examples:– Electrical outlets along walls in your house/school– Portable devices (cell phones, ipods, calculators)
powered by batteries– Bolts of electricity (lightning) during thunderstorms– Static electricity on dry winter days– Solar cells converting the sun’s energy into electricity
U3e-L1
• Electricity can be used in a thousand different ways. For example: – Electric motors turn electricity into motion. – Light bulbs, fluorescent lamps and LEDs turn
electricity into light. – Computers turn electricity into information. – Telephones turn electricity into communication. – TVs turn electricity into moving pictures. – Speakers turn electricity into sound waves. – Stun guns turn electricity into pain. – Toasters, hair dryers and space heaters turn
electricity into heat. – Radios turn electricity into electromagnetic waves
that can travel millions of miles. – X-ray machines turn electricity into X-rays.
Electrical Technology
U3e-L1
ELECTRONS
• Electricity begins with Electrons.
ATOMS• Electron cloud surrounds an atom’s
nucleus• Nucleus is made of
• Electrons – negative charge• Protons – positive charge• Neutrons – zero charge
(neutral)
Protons and Neutrons
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LOAD
• Power Source – with positive and negative terminals.
• Conductor – the path the electrons travel along.
• Load – this is what the electricity powers (e.g. motor, light bulb)
CIRCUITS
• The paths that electrons travel are called circuits.• Circuits must consist of three things:
ELECTRONS move from negative ( - ) terminal to positive ( + )
terminal
• Moving electrons have energy. • Electrons moving through a wire
(conductor) in a circuit have energy.• As the electrons move from one point to
another, they can do work.• Electrical Technology harnesses the
energy of electrons to do work.
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CIRCUITS
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CONDUCTORS
• Conduct – from Latin for “leading, guiding.” • A conductor is any material that allows electrons
to easily flow.• Remember the atom:– Conductors’ electrons are not tightly bound to the atom.– Conductors have free electrons.
• Which material has free electrons, Wood or Metal?
• Metals conduct electricity easily.
U3e-L1
• Insulate – from Latin for “separate, divided.” • An insulator is any material that impedes the
flow of electrons.• Remember the atom:– Insulators’ electrons are tightly bound to the atom. – Because the electrons don’t move, insulators cannot
conduct electricity very well, if at all.
• Which material has bound electrons, Wood or Metal?
• Wood does not have free electrons.
INSULATORS
Cotton
Bound Electrons
GoldWoodPlastic
SilverAluminum
Air
Copper
Free Electrons
U3e-L1
INSULATOR
BOUND ELECTRONS
CONDUCTOR
FREE ELECTRONS
Cotton
WoodPlastic
Air
Copper
AluminumGold
Silver
HOMEWORKHOMEWORK
1. Identify 5 electrical technologies not mentioned in class today
• (Remember, an electrical technology produces, stores, controls, transmits or gets work from electrical energy)
2. Identify the problem that the technology system solves
3. List the technological subsystems that are used in the technology
4. Identify the technology that preceded it (i.e. what was used before the technology was invented?)
EXTRA CREDIT: Air is an insulator. Come to class tomorrow and explain how lightning happens.