Current Electricity Flashcards
Electric Circuit
Continuous path in which electrons can flow
Load
The part of an electric circuit that converts electrical energy into other forms of energy
Switch
A device in the electric circuit that controls the flow of electrons by opening and closing the circuit
Electrical energy
Energy provided by the flow of electrons in an electric circuit
Electric Cell
A device that converts chemical energy into electrical energy
Primary cell
An electric cell that may only be used once
Secondary cell
An electric cell that can be recharged
DC
Electrons flow in one direction
AC
Electrons move back and fourth
How is electricity generated?
•Electric generating stations convert mechanical energy into electrical energy
•External energy source pushes blades of turbine
•Turbine is connected to generator
•Coil of wire held 2 poles of magnetic generator
•Electrons flow in wire
•Move in transition lines to electrical outlet
How do fossil fuels work?
•Fossil fuels are burned to heat water
•Creates steam
•Spins turbines
•Chemical - Thermal - Mechanical - Electrical
Advantages to fossil fuels
•Cheap
•Employs a lot of people
•Infastructure already exists in many places
How does nuclear energy work?
•Lake water
•Creates steam
•Nuclear generating stations
•Electrical energy
Advantages/Disadvantages to nuclear energy
•Does not directly cause acid precipitation
•Radiactive waste
•Affects aquatic ecosystems
•Pollution
•Habitat loss
How does hydro-electric energy work?
•Dam
•Resevoir
•Flow of water
•Turbine
•Generator
•Long distance power line
Advantages/Disadvantages to hydro electric
•No pollution
•Dams affect watersheds
•Migration of fish disrupted
•Land areas may flood
How does wind energy work?
•Wind
•Turbine
•Generator
•Electrical energy
Advantages/Disadvantages to wind
•No pollution
•Easily removed or added
•Difficult to generate a steady supply
How does Solar/Photovaltic energy work
•Light
•Solar panels
•Solar cell
•Electrical energy
How does Solar/Photovaltic energy work
•Light
•Solar panels
•Solar cell
•Electrical energy
How does biomass energy work?
•Biomass (waste)
•Steam
•Turbines
•Generator
•Electrical energy
How does biomass energy work?
•Biomass (waste)
•Steam
•Turbines
•Generator
•Electrical energy
Advantages/Disadvantages to biomass
•Continous supply of waste
•Releases methane that is later burned
How does geothermal energy work?
•Heat from crust
•Hotsprings/geysers
•Pipes
•Steam
•Generator
•Electrical energy
Advantages/Disadvantages to geothermal
•Produces large amounts of energy
•Releases CO2
•Greenhouse effect
•Increases the Earth’s temperature
How does tidal energy work?
•Tide
•Tidal generating station
•Water turbine
•Generator
•Electrical energy
Advantages/Disadvantages to tidal
•No pollution
•Difficult to find an area to build generating stations
Ontario Energy Usage
Wind - 1%
Nuclear - 52%
Coal - 18%
Natural Gas - 8%
Hydro - 21%
What is resistance
•Determined by how easily electrons can flow
•Measure of how much electrons are slowed down when passing through a conductor
•Measured in Ohms
Resistor
Restricts/slows the flow of electrons to protect the circuit
How is resistance useful
•By slowing e- flow, can convert electrical energy into other forms of energy
•Allows us to use electricity for heat/light
Things that affect resistance
•Type of material
•Temperature
•Cross sectional area/Diameter
•Length
Hazards
•Materials w/ higher resistance require more voltage to make e- flow
•If current is too high for wire, wire will overheat/cause a fire
•Short circuits
Short circuit
When there is no electrical load in the circuit and the circuit overheats and catches fire
Preventing an electrical fire
•Insert a device into circuit that will break/open the circuit if e- flow is too high for wire
•Reatrict the current to a safe level
Fuses
•Piece of metal that will melt/break the circuit if circuit temperature is too high for wire
•Different ratings (15A, 5A)
•One time use
Circuit breaker
•That will bend and flip open the circuit by breaking flow of e-
•Is reusable
GFCI
•Ground Fault Circuit Interrupter
•Shuts off electricity at the outlet if it’s overloaded
Conventional current
Positive to negative
Electron flow
Negative to positive
Amps
Measures current (I)
Voltage
•Potential difference
•Difference in electric potential energy per unit of charge measured at 2 points
Adding more lights in SERIES
Lights get dimmer
Adding more lights in PARALLEL
Light remains the same
Time of use
Electricity costs more/less depending on the time of day/week you use it
Tiered pricing
Once you use a certain amount of electricity, all electricity used after that is an additional charge
Efficiency
Eff = eOut/eIn
Power
P=E/t
P= I×V
Energy
E=P×t