# Homework Help: Power/ Source Transformations

1. Apr 23, 2010

### electronicxco

1. The problem statement, all variables and given/known data

Find the power dissipated by the 8 ohm resistor.

This was an example for source transformations.

2. Relevant equations
P=VI=V^2/r=I^2*R
V=IR

3. The attempt at a solution
First I transformed the 1 amp current source and 20 ohm in parallel
to a 20 V voltage source and a 20 ohm in series .
Then I added the two 20 ohms now in series for Req= 40 ohms.
Then I converted the 10 volt voltage source and the 10 ohm in series to a 1 amp current source in parallel with a 10 ohm resistor.

Now Im stuck , I dont feel like I should get the equiv.resistance of the 8 and 10 ohm resistors left in parallel ( because its asking for the power dissipated by the 8)

Can someone please guide me through this problem, what I'm doing wrong, or the proper approach.

Thank you

2. Apr 23, 2010

### Staff: Mentor

Just write the 2 KCL equations on the circuit that you show, and solve. Call the bottom of the circuit ground, and write the KCL for the two nodes at the tops of the two vertical resistors.