series and parallel circuits

Why do components in a series have the same current passing through them

there is only one path for current flow

why do components connected in a parallel have the same potential difference across each of them

since energy has to be conserved the energy transferred around the circuit by the electrons is the same whichever path the electrons follow

For components connected in series:

• there is the same current through each component
• the total potential difference of the power supply is shared between the components.
• the total resistance of two components is the sum of the resistance of each component.

For components connected in parallel:

• the potential difference across each component is the same
• the total current through the whole circuit is the sum of the currents through the separate components
the total resistance of two resistors is less than the resistance of the smallest individual resistor.

calculate the resistance of two components in a series

R1 + R2

why does adding resistors in series increase the total resistance

the two resistors have to share the p.d
The current is the same in every single component in the circuit, so the more resistors we add, the harder it is for current to flow

Why does adding resistors in parallel decrease the total resistance?

because there are more paths for the current to pass through