Hey guys, so here's the whole topic summary for aqa phyics electricity
electricity now this has so many practicals in they are absolutely key and
important if you want to list what the core practicals for this and all the other ones you can go over to website get my
free version guide or you get on Amazon you
Need to know all of these circuit symbols, I've made you handy flashcards for this, but here is a quick recap
This is a cell. This is a battery
You'll notice that a battery is more than one cell put together here. We have an ammeter
Voltmeter a
Lamp or a bulb
diode an
LED light emitting diode resistor
Variable resistor
Fuse thermistor
LD our light dependent resistor
Close switch
I can switch
here we have a circuit in series where you can run your finger the whole way through from the battery to all the components and
Here we have a series in parallel where it has like branches or ladders you can't run your finger around
Everything without going over something's wife
You'll notice here
We have an anteater that is in series and our voltmeter that has to be in parallel around the component
Charge is the value of electricity flowing through circuits
Current is flow of electrons
Potential difference is what pushes the current around
And resistance is anything that slows down the current
Charge equals current times time
Charge is measured in coulombs
Current is measured in amps time is measured in seconds
Potential difference equals current times resistance
Potential difference is measured in volts current is measured in amps resistance is measured in ohms
There are three current potential difference across you expected to recognize and remember current
here is measured in amps average age difference is measured in volts a
Resistor at a constant temperature the current and potential difference are directly proportional to each other
For a filament bulb we have our graph going through a zero looking like this
this is was as the temperature increases the resistance increases and
A diode will only let current flow in one direction so the graph looks like this the direction that it is pointing
But there was still using stuff like your central heating and it's only getting at current flow at certain temperatures
For example at the high temperature our graph looks like this
Whereas our low temperature the graph is going to look much lower
So as the temperature changes the resistance changes
for a light dependent
resistor whether the lights are on or off is going to depend on the quantity of lights we can use this and streetlights or
security lighting
If we have a bright light
That's what I'll graph is going to look like but then if I like dims it is going to change
So that resistance flowing through the circuit changes with the amount of lights
We can think of current as
electrons moving around our circuits and in a series circuit
They all move in the same way they all be for the same path
So wherever we look in a series circuit the current is going to be the same?
However in a parallel circuit that current comes out the battery all of this is going to pass the first ammeter
move down here
And then when it gets this point it has two choices of where to go in though this way past this a metal or down
Here in this way past this ammeter
So the current gets split
Peled your difference measured by a voltmeter
when I measure the voltmeter around the battery then a voltmeter around each of the bulbs and you'll notice that the
Potential difference the voltage at the battery is splits across the components
Whereas in a parallel circuit
The potential difference that we have here across the battery is the same as we have across each of the branches
Our
Circuits are getting quite complicated out. I'm against me looking out resistance when we have resistors are in series
The total resistance is just them added together
Whereas when we have resistors that are in parallel the total resistance is one favored
Resistance or resistant one plus one over resistance number is number T. And I decided on so
Current in a series circuit is going to be the same wherever you looking it
But you have to add up different potential differences to get the total potential difference and add up the different
resistances to get the total resistance
on a
Parallel circuit the current on each branch is going to equal to the total current
but the potential difference on each branch is going to be the same to find the total resistance you need to do one over the
resistance on each branch
Mains electricity in the UK is 230 volts and 50 Hertz
Inside plug socket we have a fuse which has a very small bit of wire going through it
we can see from the circuit symbol for a fuse wire going all the way through and
This wire will melt if too much current goes through it's that's a safety feature of the plug
We have a live wire the earth wire which is another safety feature
Plug the neutral wire the pins holding them down the cable grip another safety feature making sure that
The Y doesn't go anywhere the cable which is doubly encased in plastic
This is encased in plastic then this is encased in plastic
again another safety feature of the plug and the plastic casing and another safety feature of the plug
Power is equal to potential difference times current
Power is measured in watts. That is a capital W. 20 difference is measured in V. And current is measured in
amps
Power is equal to the current squared times the resistance
Power is measured in what capital W. Current is measured in amps and resistance is measured
homes a
Lot of Matson's for you, so here is a quick little duckling breaks or refreshes or a bit more ISM
Energy is equals power times time
Energy is measured in joules as capital J. Power is measured in watts with a capital W and time
settings with the lowercase s
Energy is equal to charge times potential difference
Energy is measured in joules
charge is measured in coulombs and
Potential difference is measured in volts
The National Grid is how we get electricity from power stations to our houses
The power stations generate the electricity and they moved to a step-up transformer
And then through a network of cables and pylons this gets moved across country to a step-down
transformer and then into our houses
Step up and step down transformers are important part of our National Grid
They work by having a varying number of coils on each side depending whether it's step up or step down transformer a step up transformer
totally low voltage into a high voltage
so that the
Energy Humira system electricity can move through a system with less energy loss making it more efficient
Or as I said an tracks will more take it from high voltage into a low voltage, so it's safe to be in our homes
When we have static electricity we have an object that isn't normally being charged becoming charge thousands when two insulators rub together
this is hoarse by the movement of electrons from one thing to another thing and you're going to get a
Shock when the charges reset and when you touch something metal if you have two charged objects coming together
They're going to repel each other
Alternatively if you have a charged objects m and a drop date, which has the opposite charge. They're going to attract each other
