Example 1:  Write down KCL equations for all of nodes.

Solution:

The KCL equations for nodes 1 through 4 will follow

Sum of leaving currents +   Sum of entering currents =0

For node 1

                                      I₁ + I₂ - I₅ = 0               // I_{2 ,} I₁  are entering and I₅ is leaving

For node 2

                                     -I₂ +I₃ -50I₂ = 0            //  -I₂  is leaving and I₃ is entering

For node 3

                                      -I₁ + 50I₂ + I₄ =0            //   -I₁  is leaving & I₄ is entering

For node 4

                               I₅ - I₃ - I₄ = 0                    //       I₅ is entering &- I₃, - I₄ are leaving