Transcript Slide 1

Voltage
This is basically the force that 'pushes' electrons around
a circuit...ie gives them energy.
A voltmeter measures the difference in energy between
2 points in a circuit
Always wired in parallel
Current
This is the flow of electrons around a circuit...
(like the current in a river)
Measured in Amps
1 Amp = 1 coulomb of electrons per second
(a coulomb = 6 x 1018)
(think of a coulomb as a 'bunch')
Always wired in
series
So we wire them like this
Power
This is the rate at which electrical energy is used.
Power = Volts x Amps
P=VI
Way you go then....measure something!
Don't forget that P also = E / t
(same formula as our force / motion topic)
Resistance
This is the measure of how much something opposes the flow of
electrons (ie opposes current)
Volts = Current x Resistance
V= IR
or with a wee bit of algebra….
R=V/I
Resistance is measured in ohms, symbol: Ω
Diodes
sneaky wee current controllers...
they allow current to flow in one direction but not
the other.
Some produce light when current flows through
them, these are LED's
Where does the current go then?