Home / Basic Electrical / Kirchhoff’s Voltage Law (KVL)

Kirchhoff’s Voltage Law (KVL)

In order to present Kirchhoff’s voltage law, we must introduce the concept of a “loop”.

Starting at any node n in an electric circuit, we form a loop by traversing through elements and returning to the starting node n, and never encountering any other node more than once.

Since energy must be conserved when a charge goes around a loop, the energy given up by the charge equals the energy it gains. The same energy-conservation principle would apply if you carried a rock over a hill and back to where you started.

Kirchhoff’s Voltage Law expresses conservation of energy in terms of voltage rises and drops around a loop in a circuit.

KVL Definition
The sum of the voltage drops around any loop equals the sum of the voltage rises.

An alternate statement of KVL can be obtained by considering voltages across elements that are traversed from plus to minus to be Positive in sense and voltages across elements that are traversed from minus to plus to be negative in sense (or vice versa). Under this circumstances, KVL has the following alternative form:

KVL Alternate Form
The algebraic sum of all voltage drops around any loop equals zero.

Specifically, this statement becomes,

\[\sum V=0\]

By applying this form of KVL to the circuit shown in figure 1, and selecting a traversal from plus to minus to be positive in sense, around the loop, we get

$E-V=0$Kirchhoff's Voltage Law CircuitFigure.1: Kirchhoff’s Voltage Law Circuit

Kirchhoff’s Voltage Law Solved Example

Find  V1  and  V2 using Kirchhoff’s voltage law.Kirchhoff's Voltage Law Example


By using Ohm’s Law,



Using KVL;







Application of KVL

         A very simple application of KVL is to combine all voltage sources in series.


In above circuit, we observe that polarity of  V1 and  V2 is same as supply voltage  Vab so we consider them positive voltage while V3 polarity is opposite to supply voltage. So, the final resultant voltage will be;


About Ahmad Faizan

Mr. Ahmed Faizan Sheikh, M.Sc. (USA), Research Fellow (USA), a member of IEEE & CIGRE, is a Fulbright Alumnus and earned his Master’s Degree in Electrical and Power Engineering from Kansas State University, USA.

Check Also

Electrical Symbols | Electrical Drawing Symbols

A symbol is a simple graphical representation of some type of component, device, and load …


  1. Fantastic goods from you, man. I’ve understand your stuff previous to and you are just
    extremely great. I actually like what you have acquired here, certainly like what
    you are stating and the way in which you say it. You make it entertaining
    and you still care for to keep it wise. I can not wait to read far more from you.

    This is actually a tremendous web site.

Leave a Reply