Question
State Kirchhoff's rules of current distribution in an electrical network. Using these rules determine the value of the current I1 in the electric circuit given below.

Answer

Junction Rule: At any junction of several circuit elements the sum of currents entering the junction must be equal to the sum of currents leaving it.

Loop Rule: Algebraic sum of changes in the potential around any closed loop must be zero.

 

Loop ABCFA

$\text{I}_{1} + 2\text{I}_{3} = 2 ........................$ (1)

Loop FCDEF

$2\text{I}_{3} + \text{I}_{2} = 6 .................................$(2)

At F, $\text{I}_{1} + \text{I}_{2} = \text{I}_{3} ........................................$(3)

Solving (1), (2) and (3)

$\text{I}_{1} = - 0.8 \text{A}$

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