electricity Flashcards
current
size of current
the flow of electrical charge
rate of flow of charge measured in ameters
electrical charge will only …
flow around a complete ( closed ) circuit
if there is a potentail difference
current can only flow if …
theres a source of potentail differnce
potentail difference
driving force that pushes charge around a circuit
potentail difference equation
pd= currrent x resistance
V=IR
resistance
factors that effect it :
anything in a circuit that reduces the flow of current
series/parallel
length of wire
3 characteristics of ohmic conductors
constant resistance - doesnt change with the current
condtant temperature
current flowing through is directly proportional to potential difference across it
2 characteristics of filament lamps
resistance doesn’t change
when electrical charge flows through it transfers some energy to thermal store
which is designed to heat up
2 characteristics of a diode
resistance depends on direction of the current
let current flow in one difection but have a very high resistance if it is reversed
series circuit
what happens if it is disconnected?
different components connected in a line end to end
if you remove one component , the circuit is broken and they all stop
series circuit:
pd - shared
current - smar everywhere
resistance - adds up
cell pd - adds up
parallel circuit
what happens when disconnected?
each component is separately connected to power supply
if you disconect one component it wont effect the other components
parallel :
pd - same everywhere
current - shared between branches
resistor- reduces total resistance
what are electrical appliances designed to do ?
transfer energy to components in the circuit when a current flows
the higher the current,…..
the more energy is transfered to the thermal store of the conponents
