What Makes a Circuit Series or Parallel?

A series or a parallel circuit is determined by the arrangement of the circuit elements and the flow of current in that circuit.

Series Circuit

If all the elements of a circuit are arranged in such a way that the magnitude of current that flows through each element is equal to the total current in the circuit, then the circuit is said to be a series circuit.

Properties of a Series Circuit

• The same amount of current flows through each element.
• The voltage drop across each element is not the same.
• The total resistance of the circuit is the sum of the resistance of all the resistors.
• If one of the elements fails, then the current will stop flowing in the whole circuit.

Parallel Circuit

If the elements of a circuit are arranged in such a way that the magnitude of the current that flows through each element is not equal to the magnitude of the total current in the circuit, then the circuit is said to be a parallel circuit.

Properties of a Parallel Circuit

• The total current gets divided in different proportions in all the branches of the circuit. The proportion of current in each branch is given by the ‘current divider rule’.
• The voltage drop across all the parallel elements is same.
• The total resistance of the circuit if given by the formula: 1/Total Resistance = 1/R_Branch1 + 1/_RBranch2 + …1/R_BranchN
• If any one element fails, the current stops flowing only in that particular branch of the circuit where the faulty element exists.

To say in simple words, if the current in a circuit is divided into branches then it is a parallel circuit otherwise a series circuit.

NOTE: In a series circuit if ant element stops working, then it breaks the entire circuit, whereas in case of parallel circuit if any element stops working then current won’t flow only through that particular branch. This is the reason why all the appliances on our homes are connected in parallel combination.

To understand the difference between series and parallel circuits, let us first define what a circuit is.

An electric circuit is defined as a closed loop of conducting elements through which current can flow. An electric circuit basically consists of the following components:

• Voltage or a Current source
• Connecting wires
• Elements like Resistors, Capacitors, Inductors, transistors, diodes, etc.