Parallel Circuit – Concept, formulas and examples

We explain what a parallel circuit is and the formulas it uses. Also, some examples and what is a series circuit.

Parallel circuit
Parallel circuits are used in the electrical network of all homes.

What is a parallel circuit?

When we talk about a parallel circuit or a parallel connection, we refer to a connection of electrical devices (such as coils, generators, resistors, capacitors, etc.) placed in such a way that both the input terminals or terminals of each one, as well as their output terminals, coincide each.

The parallel circuit is the model used in the electrical network of all homes, so that all loads have the same voltage. If we understand it using the metaphor of a water pipe, we would have two liquid reservoirs that are filled simultaneously from a common inlet, and are emptied in the same way by a shared drain.

This type of circuit allows you to repair any connection or device without affecting the others, and also maintains the exact same voltage between all devices, despite the fact that the more devices are, the more current the electrical source must generate. Furthermore, the resistance obtained in this way is less than the sum of the resistances of the complete circuit: the more receivers, the less resistance.

The great advantage of parallel circuits is that: the independence of each network station, the possible failure of which would not alter the potential difference at the ends of the circuit at all. This is its main difference in use with series circuits.

Formulas of a parallel circuit

The total values ​​of a parallel circuit are obtained by simple addition. The formulas for this are the following:

  • Intensity. It = I1 + I2 + I3… + In
  • Resistors. 1 / RT = 1 / R1 + 1 / R2 + 1 / R3… + 1 / Rn
  • Capacitors. Ct = C1 + C2 + C3… + Cn

Parallel Circuit Example

Parallel circuit
Each bulb has its own power supply line.

A perfect example of a parallel circuit is a lamp that has several bulbs lit at the same time. In the event that one of these bulbs burns out and stops operating, the electrical flow will not be interrupted to the other bulbs, which will continue to glow. This is because each has its own parallel power supply line.

The same thing happens with the electrical wiring in our houses: this is the reason why we can have a damaged plug and use the next one on the wall, or have a burned-out lamp in the living room and be able to turn on the one in the bedroom, for example.

Series circuit

Series circuit
Series circuits have only one path for electricity.

Unlike parallel circuits, designed to maintain flow in the event of a device failure, series circuits present only one path for electricity to and from the sourceTherefore, a failure in the transmission chain would lead to the interruption of the electrical flow. Of course: at any point in the circuit the current will always be the same, but the resistance increases with each additional device connected to the circuit.