Series Electric Circuits

Subject of electrical circuits. Series-connected electric circuits. The equivalent resistance in series circuits. Total current of the series circuits. The voltage values on each resistor.

Electric Circuits

Electric circuits consist of one or more voltage supply and one or more electrical components. This electrical components may be a refrigerator, washing machine, lamp, electric motor etc. These components usually not shown in the electric circuit. Resistance is put to represent them.

All devices that use electricity have a resistance. The electric energy is consumed on resistors.

There are three types of electrical circuits. These are series circuits, parallel circuits, and series-parallel circuits.

Series Connected Circuits

In these circuits the electric current go out from voltage source and flows through components by following only one path and goes back to its source.

In these circuits, the components (resistors) added end-to-end.


In the figure is seen an electric circuit. In this circuit, the magnitude of the voltage source is 100 V. The resistor R1= 5 Ω, R2 = 3 Ω, R3 = 7Ω, R4 = 5 Ω, R5 = 10 Ω, R6 = 15 Ω.

There are a potential difference on each resistor. The value of the potential difference is equal to multiplication of value of the resistor with the current which flow through the resistor.

Because of the circuit is connected in series the same current flows through all resistor.

Equivalent Resistance of Reries-Connected Circuits

The equivalent resistance of series-connected resistors is equal to the sum of all resistance value.

The equivalent resistance of n number of resistors.

Rs = R1 + R2 + R3 + …. Rn

The equivalent resistance of the electric circuit that seen in the above figüre

Rs = 5 + 3 + 7 + 10 + 10 + 15

Rs = 50 Ω

The Equivalent Current Of In Series Circuits

The total current of the series circuits is equal to current that passing through any resistor.

The total current of series circuits is found as shown below.

I = V

The total current of the electric circuit that seen in the above figure

I = 100

I = 2 A

Voltage On Resistors Connected In Series

Voltage on any resistor is equal to the multiplication of the resistor value by the current that flow through the resistor. The sum of the voltage of all resistors is equal to the source voltage.

V1 = I . R1

V2 = I.R2




Vn = I.Rn

Let we find the voltage on each resistor in the above figure.

V1 = R1 . I

V1 = 5.2 = 10 V

V2 = I . R2

V2 = 2.3 = 6 V

V3 = I. R3

V3 = 2.7 = 14 V

V4 = I.R4 

V4 = 2.10 = 20 V

V5 = I.R5 

V5 = 2.10 = 20 V

V6 = I. R6

V6 = 2.15 = 30 V

V = V1 + V2 + V3 + V4 + V5 + V6

V = 10 + 6 + 14 + 20 + 20 + 30

V = 100 V

Series Connected Electrical Circuits Questions



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