electromagnetism and motion
TRANSCRIPT
Electromagnetism and Motion
Page 85
Students will be able toDescribe a galvanometerExplain electric motorsExplain how generators workContrast AC/DC currentsDescribe how a transformers work
Electrical Energy
Occurs when you have motion between magnets
86
Galvanometers
87
Take advantage of motion to measure small currents
Motors
Three key partsArmature – Loop just like in galvanometer
Rotates in magnetic fieldBrushes – Carry charge from source
Do not moveCommutator – Carries current to armature
Attached to armature and moves.
88
Motors
88
Induction
When a wire moves through a magnetic field
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Induction
95
Or move a magnet through wires
Direct Current
DCThe electric current flows in one direction only
Batteries
96
Alternating Current
ACCurrent repeatedly changes directionUsed in homes, school…Allows for easier control
Easily raised or loweredHigh for shippingLower for home
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Generators
The opposite of an electric motor
98
Generators
Turbines
99
Transformer
A device that can increase or decrease voltage
99
Types
Step-up vs Step-down
100
Devices
Big equipment – Step up voltageFluorescent lights, TV
Small stuff – Step downElectronic games, ipod, CD player… (12V)
101
Question of Day
You are a television reporter covering the opening of a new dam that generates electricity. Write a short news story describing how a dam transforms mechanical energy from the motion of the water into electrical energy.