The two types of circuits which are commonly used to supply electrical power are series circuit and parallel circuits. The main principle of any electrical circuit is to supply electricity for an electrical device. This article gives you an insight on Series Circuit, working principle, characteristics of Series Circuits, applications, advantages and disadvantages.

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**What is a Series Circuit**

The circuit in which the electricity has to pass through all the components in the circuit and has no alternate path is termed as a Series Circuit.

In this circuit all the components are connected in the same loop. The most common example of Series-Circuit is fancy lights or string lights.

**Fig. 1 – Example of Series Circuit**

## 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.

**Fig. 2 – Schematic Representation of Series Circuit**

**Characteristics of Series Circuit**

Below are the important characteristics of Series Circuits:

### Resistance

**R _{T }= R1+R2+R3+…..R_{n}**

Where R_{T} = Total Resistance

If R1=10Ω,R2=20Ω,R3=40Ω

R_{T} = 10+20+40

R_{T} =70Ω

**Current**

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

**I=V/R** = 10/70= 1/7 Amp =0.1428 Amp= 142.8 milliamps

I=142.8 milliamps

**Voltage**

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

**V=IR**

Let’s call voltage across the resistor 1, 2, 3 as E_{R1,} E_{R2 }and E_{R3 }respectively.

**E _{R1}= IxR1** =0.142 x 10 = 1.42 v

**E _{R2}= IxR2**=0.142 x 20 = 2.84v

**E _{R3}= 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,

**E _{T}= E_{R1}+ E_{R2 }+E_{R3 }**= 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.

**Advantages of Series Circuit**

The advantages of Series Circuits include:

- Easy to design and build the circuit.
- If a component breaks, the current flow stops.
- It acts as a current regulator.
- The cost to build a Series Circuit is less compared to Parallel Circuit.

**Disadvantages of Series Circuit**

The disadvantages of Series Circuits include:

- If a single bulb in series is blown, then no current will flow in the circuit.
- If the load is increased i.e. if more bulbs are connected then the light gets dimmer.

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Laxmi is a B.E (Electronics & Communication) and has work experience in RelQ Software as Test Engineer and HP as Technical support executive. She is an author, editor and partner at Electricalfundablog.