Difference between Series and Parallel Circuit

Differences Electronics & Electrical Circuit

Series and Parallel electric circuits are heavily used in various applications such as resistive series circuits, voltage divider circuits, home appliances, etc. It is important to have a good knowledge of how these circuits work. Go through this article to get an overview of how Series and Parallel circuits operate and how they differ from each other.

What is an Electric Circuit?

An electrical network which has closed path for electric current to flow is known as electric circuit or circuit. An electric circuit consists various circuit elements such as energy sources, resistors, inductors, capacitors, etc. An electric circuit must have at least one source of energy.

Based on the manner in which the circuit elements are connected, the electric circuit is classified into following two types −

Series Circuit
Parallel Circuit

What is a Series Circuit?

An electric circuit in which the circuit elements are connected one after the other (or in cascaded manner) is known as a series circuit. In a series circuit, the second terminal of first element is connected to the first terminal of the second element as shown in the figure below.

As from the connection diagram of the series circuit, it is clear that all the circuit elements are cascaded in a single line, thus same current passes through all the elements while the voltage across each element is different.

What is a Parallel Circuit?

An electric circuit in which starting terminals of all the elements are connected together at a common point, while the ending terminals are connected together at another common point is known as a parallel circuit. The connection diagram of the parallel circuit is shown in the following figure.

From the diagram of the parallel circuit is can be seen that the number of paths for current to flow is equal to the number of parallel branches in the circuit and different current is flowing through each branch based on the value of element. Also, all the parallel branches are connected between the common points, thus the same voltage exists across all the elements.

Differences between Series Circuit and Parallel Circuit

The following table highlights the key differences between a series circuit and a parallel circuit.

Parameter	Series Circuit	Parallel Circuit
Definition	When the circuit elements are connected one after the other (or back to back), then circuit is called a series circuit.	When all the elements are connected such that the starting terminals are joined together and ending terminals are joined together, then the circuit is called a parallel circuit.
Circuit current	In a series circuit, all the circuit elements share the same current.	In case of parallel circuit, the current flowing through each element is different.
Voltage across elements	The voltage across each circuit element is different in a series circuit.	The voltage across all the elements remain the same in the parallel circuit.
Number of paths for current flow	In a series circuit, there is only one path for current to flow.	In a parallel circuit, the number of paths for current to flow depend upon the number of elements connected in parallel.
Effect of fault	In a series circuit, the fault in a single circuit element interrupt the operation of the complete circuit.	In a parallel circuit, the fault in a single circuit element does not affect the operation of rest of the circuit
Fault troubleshooting	The determination of faulty section and troubleshooting of the fault is difficult in a series circuit.	It is very easy to find and rectify the fault in a parallel circuit.
Equivalent resistance	For a resistive series circuit the equivalent resistance is given by,$$R_s\:=\:R_1\:+\:R_2\:+R_3\:+\dotsm$$	For parallel resistive circuit, the equivalent resistance is given by,$$\frac{1}{R_p}\:=\:\frac{1}{R_1}\:+\:\frac{1}{R_2}\:+\:\frac{1}{R_3}\:+\dotsm$$
Equivalent inductance	The equivalent inductance of a series inductive circuit is given by,$$L_s\:=\:L_1\:+\:L_2\:+L_3\:+\dotsm$$	The equivalent inductance of a parallel inductive circuit is,$$\frac{1}{L_p}\:=\:\frac{1}{L_1}\:+\:\frac{1}{L_2}\:+\:\frac{1}{L_3}\:+\dotsm$$
Equivalent capacitance	For a series capacitive circuit, the equivalent capacitance is given by,$$\frac{1}{C_s}\:=\:\frac{1}{C_1}\:+\:\frac{1}{C_2}\:+\:\frac{1}{C_3}\:+\dotsm$$	For a parallel capacitive circuit, the equivalent capacitance is determined by,$$C_p\:=\:C_1\:+\:C_2\:+C_3\:+\dotsm$$

Conclusion

From the above discussion, it can be concluded that there are various differences between a series circuit and a parallel circuit. In a series circuit, the current flowing through all the elements remain the same while in a parallel circuit, the voltage across each element remains the same.

Both of these circuits are extensively used in various applications like a resistive series circuit as a voltage divider circuit and parallel combination of house appliances, etc. Hence, the knowledge of these differences can help an individual to select either of them according to the requirements.