A series circuit is laid out such
that the components are connected end to end. This forms a single
circuit or loop from one side of the voltage source to the other. A
series circuit has only one path for current to follow.
A series circuit
There is only one possible path for current to follow in a series
circuit. The current in a series circuit flows equally through all
components. In the example above the total current is 1 ampere. The 1
ampere flows through each of the resistors as it flows through the
complete circuit. This is much like a horse race. If there are 10
horses in a race, those 10 horses will all travel completely around the
track, taking each turn and straight in succession. No matter where an
observer is around the track, he will see the same 10 horses go by as
any other observer.
The total resistance in a series circuit is equal to the sum of the
individual resistances in the circuit. This can also be expressed with
the following formula:
RT = R1 + R2 + R3 (etc.)
RT is the total resistance of the series
R1, R2 and R3 are each of the resistors in the circuit.
In the preceding example, there is a total of 45 ohms in the circuit,
the sum of 10 ohms, 15 ohms and 20 ohms.