Calculating Voltage and Power with Nodal Analysis

2 replies · 4K views · last reply
math_04
Messages
21
Reaction score
0

Homework Statement



Consider the circuit shown (attached). Calculate the voltage v and calculate the power for the 2A current source. In this particular case, is it supplying or absorbing power?

Homework Equations





The Attempt at a Solution



I know that there is 2A flowing around the circuit so no point in using loop equations. I don't think nodal analysis would be of much help or would it?
 
Attachments
  • Circuit schematic with a 20 V source and 2 ohm resistor on the left branch, a 10 V source across the top, a 15 V source and 5 ohm resistor on the right branch, and a 2 A current source labeled V at the bottom right.
    Circuit.JPG
    6.2 KB · Views: 487
You're right, there's no need for loop equations. In this case just mark out all the nodes, and taking into account the direction of the current in the circuit, calculate the voltage at all the nodes using an arbitrary starting point of 0V in the circuit, remembering to minus potential when you cross over from + to - of a circuit element and add potential when you do the opposite. You should be able to get the potential at the point just above the 2A current source.

From there you can calculate the power absorbed/supplied by the source.
 
I would use KVL and the conservation of energy in a loop for a beginning.Since we know the value of each independent source, followed by convention sign we should be able to figure out how much energy left across the resistor. If the left energy is negative , then it is supplying the power. If it is a positive, then is is observing the power.