Current: rate of flow of charge round
the circuit, current will only flow
through a component if there is a
voltage across that component
Unit: ampere (A)
Voltage (potential difference):
the driving force which pushes
the current round
Unit: volt (V)= 1 joule/coulomb
Resistance: Anything
in a circuit that can
slow the flow down
Unit: ohms (Ω)
The voltage and the resistance are
doing opposite things so they decide
how big the current will be. If you
increase the voltage in a circuit then
more current will flow, and if you
increase the resistance then the
current will decrease and slow the
current down
Potential difference (Voltage):
Energy transferred per unit of
charge passed
Energy is transferred due to a
change in potential difference
The energy from
the battery/cell is
supplied to raise it
through the voltage
The charge lowers whenever it
goes through a component
anywhere in the circuit
The bigger the
voltage/potential
difference, the
more energy
transferred for a
given amount of
charge passing
through a circuit
In a circuit a battery
with a bigger voltage will
supply more energy for
every coulomb of charge
that flows around it
Current is conserved at a junction in
a parallel circuit so no current is lost
or used up. At junctions current
either splits or re-joins at points in
the circuit
This means that the total
current entering a junction
is equal to the total current
leaving a junction