In the Norton/Thevenin theorem, what is the definite difference between the load resistance and Thevenin/Norton resistance?
I cannot find any sources defining the difference, all of the sources use them as if I already were to know the difference.
Take this example.
Here I know the load resistance is the 40 ohm resistor. But not really why. Is it because of the direct connection to ground? If the circuit was more complex, I might not have been able to see it as clear as in this picture, because I don't really know what qualifies 'the load resistor' to differ from the rest of the circuit.
Best Answer
In the example you've posted, we see two Thévenin circuits that share a 40-ohm load resistor. But the question is what differentiates between the "load" resistor and the "Thévenin" resistor.
I've redrawn the circuit below:
simulate this circuit – Schematic created using CircuitLab
The Thévenin equivalent circuits are enclosed in boxes as shown.
Alone both Thévenin and Norton circuits have open-ended terminals. Whatever impedance is found across those terminals is deemed the "load" that the equivalent circuit is driving.
For a Norton equivalent, we would see the following circuit:
simulate this circuit