Write down the Mesh Current and NodeVoltage matrix equations

Write down the Mesh Current and Node-Voltage matrix equations for this circuit. Use either of the above to find the power dissipated by the 30 ohm resistor. Is the current source absorbing or generating power? Explain. Find the power dissipated by the 30 ohm resistor in Q1 using superposition. Using your superposition results of Part (A), what will the voltage be across the 30 ohm if the current source value is doubled?

Solution

1. USE NODAL ANALYSIS

LET VOLTAGE ACROSS 30 ohm resistor is V2

use kcl

4 + 100- v1/ 20 = v1 - v 2/10

3v1 - 2v2 = 100

use kcl at node

v1 - v2/10 = v2 /30 + v2 - 50/25

solve above 2 equation

we get v2= 80 V

B) power dissipation through 30 ohm resistoor = 80² /30

= 213 W

C) In this current source will deliver power