# (Ideal) Amplifier networks/nullors - determining the gain

I am having trouble understanding how the different amplifier networks actually do "their magic". In these networks a nullor is a unite that has always 0 voltage over the input and no current through it. The output has infinite power to match the requirement set. The "easiest" version -a voltage to voltage amplifier- I can easily understand:

Because the current and voltage over the input of the nullor is 0 the voltage at the output must follow the equation $V_s = V_{load} \cdot \frac{R_2}{(R_1 + R_2)}$

However I do not see how this works in other types of amplifiers; say the following standard "voltage-to-current" amplifier setup:
What is the gain here? And what is the equality equation to solve?

• This makes no sense without a clear definition of what "nullor" is. – Andy aka Nov 5 '13 at 15:48
• @Andy aka Nullor is a well know theoretical circuit component. – AndrejaKo Nov 5 '13 at 16:04
• @AndrejaKo I recognize the op-amp and transistor implementation but I've never heard of it before!! – Andy aka Nov 5 '13 at 16:07