Here is the circuit. Note I am using the actual measured values for the resistors. I remove RL and short V1 and I have (R1 II R3) + R2 = 748.9Ω. With V1 jumpered, I actually measure 748.96Ω from A to B. With the load resistor in place and voltage on the circuit, I get 2.709V for the first circuit and 3.2V for the Thevenized circuit in LTS??? I actually measure 3.68V across RL with the circuit breadboarded? Using a potentiometer set for 745Ω (as close as I can tweak to Rth) I get 5.21V? So I am obviously not Thevenizing this correctly. Will someone please give me a clue to the error I am making. Thx Sam

 

Why both of your circuits have 10V? Why did you not Thevenized the V1?

 

Arghhh yes I did and came up with 7.08V! And using that across the pot gives me the exact answer! Thx Jony!