Most real circuits mix the two connections. This lesson's skill: look at a combined circuit and say which components are in series and which are in parallel.
Here is a battery with resistors P and Q on one loop.
Every charge passes through P and through Q, one after the other. So P and Q are in series.
Now the same battery, with P and Q rewired onto separate branches between the same two junctions.
A charge passes through P or through Q, never both. So P and Q are in parallel.
Now a third resistor, N, joins on the single path before the branches.
Every charge passes through N. So N is in series.
P and Q are unchanged: a charge still passes through P or through Q, never both. So P and Q are still in parallel.
Is N in parallel with P? No. N does not sit on a separate branch beside P. Every charge that passes through P also passes through N. So N is in series with the parallel pair.
In the combined circuits you will meet, the shape is one parallel pair plus one resistor on the single path. Spot the pair first; whatever sits on the single path is in series with it.
A circuit runs from the battery through resistor J, then splits into two branches holding K and L, which rejoin and return to the battery. Which components are in parallel?
K and L sit on separate branches between the same two junctions.
A charge passes through K or through L, never both.
K and L are in parallel.
In the same circuit, how is resistor J connected?
Every charge passes through J on its way to the branches.
J is in series with the parallel pair.
In the circuit shown, which components are connected in parallel?
In the circuit shown, which component is in series with the parallel pair?
In the circuit shown, how is resistor Y connected?
In the circuit shown, which two components are connected in parallel?
Which statement describes the circuit shown?
In the circuit shown, how is resistor M connected, relative to resistors V and X?