Current electricity Flashcards
current electricity
controlled flow of electrons through a conductor
a steady flow between two objects
used to power devices
electric circuit
continuous path where electrons can flow
includes: energy source, load, wires, sometimes a switch
energy source
could be small and portable like a battery
or large like a generating station
load
something on a circuit that converts electrical energy to another form of energy
ex: lightbulb= electrical energy- light energy
switch
controls the flow of the electrons by opening or closing the path
wires
joins all parts together creating a pathway that has to be full circle
copper/ aluminum,
electrical energy
energy provided by the flow of electrons in a circuit
measured in joules
makes devised work
sources of electrical energy
can be a better which gives small amounts or
electric generating systems which gives large amounts from wires to your home
electric cells
a device that converts chemical energy to electrical energy and is portable
is consists of two electrodes (a negative and a positive)
and a electrolyte that is the source for electrons
the electrons leave the negative side (repelled) and go in the positive side (attract)
primary cells
electric cell that can only be used once because the chemical reactions they produce cannot be reversible
they cannot recharge
secondary cells
electric cells that can be recharged and used multiple times
like how you can recharge batteries
and reverse the chemical reactions
fuel cells
kind of electric cell where a continuous supply of chemicals is pumped as the cell operates
waste products are removed
and they can operate longer
direct current
flow of electrons in one direction around the circuit
produced by a cell
powers portable electric devices
alternating current
flow of electrons alternates direction in a electric circuit, goes back and forth
works in a generator not a cell
distributing energy over long distances
generating electricity
electrical generator takes energy produced by a non electrical source and converts it to electrical energy
uses one type of energy to make another
how does a generator work
external evergy– turns turbine– turns a coil witha magnet on it– send electrons up the coil– electricity– wires–homes
sir Micheal Faraday
invented the generator
providing a constant flow of electrons
generating current energy
to run a current you need elecctrical energy which uses generators
generators need a external energy source
can be moving water steam or wind
moving water
pro
con
hydroelectric generation -falling water turns the turbines - comes from rivers, lakes, waterfalls, dams -180 in Canada PRO- no air or water pollution CON- (dams) changes the ecology of a area migration of fish is disrupted flooding expensive, money for taxpayers
tidal generation
uses moving water- tidal energy= energy from moving ocean water to turn turbines
twice a day
renewable
thermal generation
heating water to produce steam
steam turns turbines
fossil fuels- steam
it is energy stored in dead cells
can be burned to create steam non renewable
OLD WAY coal= pollution, CO2 heats up the earth, mercury, acid precipitation, smog
NEW WAY gas= cleaner less C02 not a lot left
radioactive materials= steam
uranium is put in a reactor and when the nucleus collide with uranium it creates nuclear fission
the nucleus break creating energy to heat water to create steam
non renewable
must be mined creating pollution and habitat loss
puts high temperature water back in lakes
radioactive waste can cause cancer
expensive/ dangerous
biomass=steam
using biological material to to burned to cream steam
renewable
may not be enough for the energy we need
geothermal energy
taking energy from deep i n the earths crust and bringing it up with pipes to be burned to create steam
renewable
no pollution
hard to get and expensive to build
wind
use a wind turbine connected to a generator
maintenance costs are cheaper
wind is free
turbines can be closer to homes with less wires
no pollution
light
device can convert light into electrical energy
ex sun
PRO renewable, no pollution, lasts a lot of years
CON little pollution, only 30% effective, expensive, not immediate
electrical power
rate at which electrical energy is produced
measured in Watts (iW=1j/second)
killowatt hour
unit measures energy usage
1000 times more than a Watt hour
efficiency
comparison of output vs input in a percentage
cost
wattage/1000= KWh x hours used in one day x price x days used
power
voltage x current
wires into house
BLACK- hot 120v in and out
RED- hot 120v in and out
WHITE- neutral to the ground
service panel
breaker box with all the wires inside it with a total voltage of 240
electricity goes through it
circuit breaker def
connects all series circuits in one spot
has many switches
neutral wire
goes to the ground to protect from electrocution
the small hole at the bottom on the plug
3 prong plugs
has 3 areas for the electricity to go
one goes to ground to stop death
how circuit breakers help
opens the circuit if the current is too high
so that it doesn’t explode or cause a fire it just stops
reusable usually 15 amps
fuses
same as circuit breakers just not reusable
ground fault circuit interpreter
detects problems with the ground wire and if its too much it turns off the breaker
used near water
polarized plugs
the fact that plugs have different sizes to make it so energy can only flow through one
it reduces the risk of shock
resistance
the flow of current measured in Ohms
when the voltage is high it means the current is also high
volts/ ampere
the total resistance of a circuit is the sum of the resistance of all the load
current
the measure of that flow rate of electric charge in a circuit
the current is the same at all points in the circuit
uses an ampere to find out the current
the symbol is I
measured in amperes
the unit symbol is A or coulombs/second
voltage
also called potential difference
measured the difference in electrical potential energy between two points in a circuit
has to be in parallel to what it is measuring
measured in voltage
the voltage of a battery would be a measure of how much force it gives the current
_______________
wire symbol
____!________
j !
connected wire (dot)
_______/_______
/
not connected wire (no dot)
’/
cell
’/’/
battery
ammeter
a A with a circle around it
/]/]/]/]/]/
resistor
./ .
open switch
_.__.__
closed switch
light bulb
circle with an X or a cursive e
motor
circle with an M
series circuit
there is only one path for the electrons to flow and all the loads are connected in that circuit
parallel
a circuit with more than one pathway for the electrons to flow
loads can be on different paths
Charge
Measured in coulombs
Q is the symbol
the amount of power emitted
Ohms law
formula. that says that
resistor’s current =resistor’s voltage/ resistance
which shows the voltage drop of the resistor,
