We need to find the power delivered by the 5V source in the above network. I usually apply superposition theorem when I need to find the power delivered by a source when there are many power sources in the same circuit. But here I am not able to understand how to approach.
First, calculate the current through the
3 Ω and
2 Ω resistors by simple Ohm's law (
I = V⁄R). The result is shown in the following figure (they are denoted by
Next task is to calculate the current through the
5V source which is denoted by
I3. We can use Kirchoff's Current Law (KCL) either at Network 1 or Network 2.
Lets say we apply KCL at Network 1. Here, we can write -
I2 + I3 = I1
I3 = I1 - I2
I3 = 2A - 1A = 1A
So, we have found the value of current through the voltage source is
1A. So, the supplied power by the voltage source is
5 × 1 = 5W.
Since you know the voltage across each resistor, you can find the current through it.
Knowing that, you can use the cut-set form of KCL to find the current through the 5 V source.
Knowing the voltage and current through the source, you can find the power it delivers to (or absorbs from) the rest of the circuit.