I'm assuming we are talking in terms of DC here to keep things simple.
Voltage is a measure of how much a single electron's energy changes across the circuit. Current is how many electrons are flowing through a circuit. Multiply those two values to get the rate of energy transfer, or power. If all you have is a measure of current, you know how many electrons are flowing through the circuit, but not how much their energy is changing.
You are correct that voltage induces current, and that voltage and current are interrelated. Ohm's law is the simplest case of that. You can derive a circuit's power from current and it's resistance using known formulas. And even more simply, if you know current is flowing you know the circuit is dissipating power, even if you don't know how much (as the other commenters have said)
Although I haven't labeled them, there are 5 interesting nodes in the network.
As drawn, your circuit contains only 2 nodes. The entire outside ring is connected by perfect wires, and so it's just one node from the point of view of circuit analysis.
Does any one have an idea on how I would go about designing the current controlled source in PSpice?
PSpice provides an "F" Element which is in itself a current-controlled current source. Simply place one of these in your circuit. The CCCS element will have a source port and a sense port.
You simply place the element so that the source port is where you show the CCCS in the hand drawing. Then connect the sense branch so that the controlling current flows through it. Normally this means breaking a wire in the hand drawing.
However, in this circuit you will have a problem because both terminals of the sense port are connected to the same node. Probably PSpice will refuse to simulate this circuit; but even if it does, the results are ambigous. In terms of your drawing, there's no reason for current from the bottom end of the V source to go by the "i1" path vs going the other way around through the yellow, purple, and red arrows.
Also, you will also have to designate one of your two circuit nodes as ground before running a simulation.
Best Answer
Your question is very specific, but I think what you're getting at is a more general concept.
In typical general-use simulators, "current sources" are modeled as ideal. An ideal current source will provide the exact amount of current requested regardless of external influences. It will adjust its voltage instantaneously as needed to continue to provide that exact current flow no matter what.
Realistic? Not at all. Any real current source will always be influenced by external forces. A sudden step change in load resistance, for example, may cause the current source to spike up or down. Or what if the load becomes open circuit? The realistic current source may attempt to raise its voltage until it fails catastrophically (or simply powers down if it's smart enough).
Using a current mirror as a realistic current source is one of many ways to model a more realistic current source. Current mirrors are very simply to build - just two transistors and a resistor - which is probably why this person suggested using them. But current mirrors exhibit properties that may not be adequate for your simulation. Sometimes an ideal current source will work just fine. Other times a more sophisticated model is necessary. As with all things electronics, it depends on your application.