Series Circuit – Concept, elements and examples

We explain what a series circuit is and the elements that compose it. Also, differences with a parallel circuit and examples.

Series circuit
A series circuit has only one path for current.

What is a series circuit?

A type of electrical circuit is called a series circuit provided with a single path for the current, which must reach all the terminals or terminals connected in the network in succession, that is, one after the other, connecting their output points with the input points of the next.

If we explain it with a hydraulic metaphor, we will have two or more water tanks arranged in such a way that the outlet pipe of one is the inlet of the next, and so on.

Series circuits supply the terminals with the same amount of current at the same identical intensity, and provides the circuit with an equivalent resistance equal to the sum of the resistances of each connected terminal, but always higher than the largest of them; this means that as we add terminals, the resistance increases (instead of decreasing, as in parallel circuits).

Series circuits are useful because they allow the sum of the voltage, especially with regard to generators; this is, allow the accumulation of network power. That is why certain devices use a certain number of batteries to power themselves: because only then can they reach the required voltage. Otherwise we would require a single more powerful and expensive battery.

Elements of a series circuit

series circuit
The conductors are made of metallic material, such as copper.

The elements that make up a series circuit are not essentially different from those of a circuit of another type. The substantial difference is how they are arranged. Thus, we have that a parallel circuit is composed of:

  • An electrical source. Where the energy that is transmitted by the conductor originates.
  • A driver. Usually made of a metallic material (copper, etc.) that goes from the source to the terminals and back, allowing the electronic flow that is electricity.
  • Terminals or receivers. What are each of the devices connected to the electrical network, which receive the current and transform it into another type of energy: light if they are light bulbs, kinetic if they are motors, etc.

Differences between a series circuit and a parallel circuit

parallel circuit
In a parallel circuit, each terminal has its own electrical flow.

A series circuit and a parallel circuit constitute opposing models. Their values, in fact, are calculated using the opposite equations. However, the great and substantial difference between the two has to do with the sustained flow of electrical current.

While a parallel circuit allows each terminal to have its own electrical flow, that is, allowing it to function separately from the rest and therefore not lose current if the neighboring terminal is damaged or interrupted, the series circuits, on the other hand, depend on the correct operation of the neighbor to continue operating, since the output of that terminal is the entrance of this one. So if a terminal is damaged in the series circuit, the entire network from that terminal onwards will lose access to power.

Series circuit examples

series circuit
Before, Christmas lights came in series circuits.

Formerly, the Christmas lights with which the tree is adorned came in series circuits, which made their production more economical, since the sum of the voltages of the series sustained the electrical voltage to make them shine, but it meant that when one of the small bulbs melted, the entire network from then on was interrupted.

Another common application of these circuits is found in certain risk machinery, which have an emergency button to turn them off. How it works depends on the interruption of a normally closed series circuit, which opens at one point and takes electricity from the entire chain, stopping the machine.