Kirchhoff’s Current Law or Kirchhoff’s First Law
Kirchhoff’s Current Law states that
“The total current or charge entering a junction or node is precisely equal to the total current or charge exiting the node, as no charge is lost at the node”.
To put it another way, the algebraic sum of all currents entering and exiting a node must be zero. Kirchhoff’s Current Law (KCL) is also known as Kirchhoff’s First Law or Kirchhoff’s Junction Rule.
Note:
Kirchhoff’s First law is similar to the Law of Conservation of charge. As a result, a Nord or junction is a point in a circuit that does not serve as a charge source or sink.
Therefore,
n∑k=1 IK = 0
Where n denotes the total number of branches at the node with currents flowing toward or away from it.
i.e.
I(exiting)+I(entering) = 0
For Example,
In the figure shown below the node or the junction has five branches. The three incoming currents, i3, i4, and i5, and the two incoming currents, i1 and i2. Hence, According to Kirchhoff’s Current Law, the sum of total incoming and outgoing currents at the node will now equal zero. Consider the current entering the node as positive and the current exiting the node as negative then the algebraic sum can be represented as
(-I1) + (-I2) + (I3) + (I4) + (I5) = 0
⇒ I3 + I4 + I5 = I1 + I2
It should be kept in mind that individual currents are not necessarily the same but the sum of currents entering and exiting are the same. It should be noted that there are no set rules for assigning positive and negative signs to the current. However, to avoid confusion entering current is taken as positive, and exiting current is taken as negative.
Kirchhoff’s Laws
Kirchhoff’s Laws are the basic laws used in electrostatics to solve complex circuit questions. Kirchhoff’s Laws were given by Gustav Robert Kirchhoff who was a famous German Physicist. He gave us two laws Kirchhoff’s Current Law and Kirchhoff’s Voltage Law which are discussed in this article.
These laws deal with the flow of current and the voltage applied in the complex circuit and provide a way to solve these complex circuits. In this article, we will learn about Kichhoff’s Current Law, Kirchhoff’s Voltage Law, their applications, examples, and others in detail.
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