# Dependent source absorbing or delivering power?

Discussion in 'Homework Help' started by bob78h, May 12, 2013.

1. ### bob78h Thread Starter New Member

May 12, 2013
2
0
I attached the questions. So I'm thinking I need to find the direction of the current through the dependent source and then use P=IV. I could use mesh analysis to do this but the question is only worth 2.5 points...So I'm thinking there must be some trick to solving it with minimal work?

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2. ### WBahn Moderator

Mar 31, 2012
18,092
4,918
It's only worth 2.5 pts because all you are doing is plugging values into the solution to the previous 15pt problem.

3. ### bob78h Thread Starter New Member

May 12, 2013
2
0
Well for the 15pt part, the answer is supposed to be left in the nodal equations, not actually solved for the specific voltages. Anyhow, could you explain how finding the voltages lets us find the power? We can find V3, but you need to find the current through 10iy, which would require solving the mesh currents (another system of equations). Am I overlooking something?

4. ### WBahn Moderator

Mar 31, 2012
18,092
4,918
If you know the node voltages, how hard is it to find the current in Vs? How hard is it to find the current in R2? Given those, how hard is it to find the current in the dependent source? If you know the current and and V3, how hard is it to find the power in the dependent source?