Series and parallal connection


In any circuit some components connect in series and some component connect in parallal. Hence one question u have how to recognize the connection  or how we can construct it. Here in this tutorial i’ll explain all these topic about Series and parallal connection.


What is Series connection?

A series connection is a circuit connection where current passing through all the connected components are same.


From this above circuit it is cleared that in series circuit the voltage is splited but the current is same.

How is a Series Circuit Built (Working Principle)

The path for flow of electrons (electricity) is called a Circuit.The intent of any electrical circuit is to supply electricity for an appliance or any electrical device.These devices are called loads. Before the load operates, electricity must have a definite path from the source to the load and back to the source.

The figure below shows a typical Series-Circuit where the Resistors (R1, R2, R3) are connected subsequently with the end of one resistor connected to the other end of the next resistor to form a loop.The current flows from negative terminal of the battery through the resistors and hence the current is same across all the components in a Series Circuit.

The total resistance in a Series Circuit is equal to sum of the individual resistances.The voltage is different across different resistors and the sum of voltage drop across each component (resistor) is equal to the applied voltage. A break in the Series-Circuit will stop the current flow across the circuit.



Characteristics of Series Circuit

Below are the important characteristics of Series Circuits:


R= R1+R2+R3+…..Rn

Where RT = Total Resistance

If R1=10Ω,R2=20Ω,R3=40Ω

RT = 10+20+40

RT =70Ω


Suppose the applied voltage (V)=10V, then the current (I) can be calculated using the formula:


 = 10/70= 1/7 Amp =0.1428 Amp= 142.8 milliamps

I=142.8 milliamps


Since the values of resistance and current are known, Voltage can be calculated using the formula:


Let’s call voltage across the resistor 1, 2, 3 as ER1, ER2 and ER3 respectively.

ER1= IxR1 =0.142 x 10 = 1.42 v

ER2= IxR2=0.142 x 20 = 2.84v

ER3= IxR3=0.142 x 40 = 5.68v

Voltage Drop

As we know that the sum of voltage drop across each resistor is equal to the applied voltage,

ET= ER1+ ER2 +ER3 = 1.42+2.84+5.68

= 9.94 volts (with rounding error) ≈ 10 V (Applied Voltage)

Applications of Series Circuit

The applications of Series Circuits include:

  • Series resistive circuits are used in low power circuits.
  • Series Circuits are used in voltage divider circuits.



  1. Series circuits do not overheat easily. This makes them very useful in the case of something that might be around a potentially flammable source, like dry plants or cloth.
  2. Series circuits are easy to learn and to make. Their simple design is easy to understand, and this means that it’s simple to conduct repairs .
  3. we can add more power devices, they have a higher output in terms of voltage .
  4. The current that flows in a series circuit has to flow through every component in the circuit. Therefore, all of the components in a series connection carry the same current.


1.If one point breaks in the series circuit,the total circuit will break.

  1. As the number of components in a circuit increases ,greater will be the circuit resistance 


What is Parallal connection:

A series connection is a circuit connection where voltage between each connected components are same.

But the current splits.

How to Make a Parallel Circuit

Two or more circuit components are connected across a common voltage source to form a Parallel-Circuit. The figure below shows a typical Parallel-Circuit where the Resistors (R1, R2, R3, R4) are connected in parallel. Both the sides of the resistors are connected directly to the voltage source. The parallel path is called a branch and the voltage across all the branches are same but the current may be different.

Characteristics of a Parallel Circuit

The primary characteristics of Parallel-Circuit are listed below:

Branch Currents in Parallel Circuit

According to Ohm’s law, I=E/R. This implies that each resistor in this circuit will draw current from the source. Hence, the total current drawn from the source is equal to the sum of the branch currents and the current flow in each path depends on the resistance of the branch. However, the voltage remains the same and creates potential difference across its terminals.

The total current (It) can be calculated using the equation,


= I1+I2+I3+…. In

Where (I1+I2+I3+….In) are branch currents

Let us consider that the parallel-circuit is built with two resistors (R1 and R2) with different values (10 Ω and 5Ω) respectively. Voltage of 10V is applied across the resistors resulting in a current of 1A drawn from battery through R1 and 2A drawn through R2 which is derived from the equation I=E/R.

Hence, the two branch currents in the circuit are 1A and 2A which sums up to 3A.

It = 1+2 = 3A

Resistances in Parallel Circuit

The total resistances of any number of resistors is calculated using the equation,

Reciprocal of R1=1/R1=1/10=0.1

Reciprocal of R2=1/R2=1/5=0.2

Sum of the reciprocals above= 0.3

Rt= 1/0.3 = 3.33 Ω

Power in Parallel Circuit

Once the total current and the applied voltage values are known, Power can be calculated using the equation P=EI. In the example above, Applied Voltage (E)=10V and I=3A

∴P= 10 x 3 = 30 W

Applications of Parallel Circuit

The applications of Parallel Circuits include:

  • The electrical wiring to the power points in every household is in the form of Parallel Circuits.
  • The dc power supply in automobile industry uses Parallel Circuits.
  • The computer hardware is designed using Parallel Circuits.



  1. Every unit that is connected in a parallel circuit gets equal amount of voltage.
  2. It becomes easy to connect or disconnect a new element without affecting the working of other elements.
  3. If any fault happened to the circuit, then also the current is able to pass through the circuit through different paths.


  1. It requires the use of lot of wires.
  2. We cannot increase or multiply the voltage in a parallel circuit.
    3. Parallel connection fails at the time when it is required to pass exactly same amount of current through the units.