# Circuit Analysis with nodal analysis

Discussion in 'Homework Help' started by Hooperoo, Apr 5, 2013.

1. ### Hooperoo Thread Starter New Member

Apr 5, 2013
1
0
Hi guys.
Im tearing my hair out over this problem, so any help would be greatly appreciated.

Im solving the circuit with nodal analysis, and following the steps of:
1: Ground node equation
2: Voltage source and current source equations
3: Equations for each resistor
4: KCL at each node apart from the ground node
5: Substituting resistor equations into the KCL equations and solving for the node voltages
6: Solve for branch currents
7: Find power consumed or supplied

The problem is, i get to step 5, find a node voltage, but apparently it's the wrong answer. It doesn't match any of the answers supplied by the teacher (it's a practice multiple choice exam).

Attached is my working, with a picture of the circuit.

I get to a voltage for node B (circled in red), however, when I sub this in to find the voltage at node A, i get the wrong answer (12.8).

2. ### t_n_k AAC Fanatic!

Mar 6, 2009
5,448
782
$\frac{V_A-V_B}{3000}=I_1=I_4=5mA$