# Finding Thevenin voltage and resistance [closed]

I am struggling to find the Thevenin voltage and resistance across terminals A and B of the given circuit.

I got as far as writing KCL at nodes 2 and 3, which gave this:

$$v_\text{AB} = - G_2/G_1 e + \frac{G_1 + G_2}{G_2} e_2$$ $$e_1 = e_2 = e_3$$

From here, I don't really know how to proceed to calculate $$\v_\text{AB}\$$. I don't even know how to start calculating $$\R_\text{Th}\$$.

• Please explain why you think nodes 1 and 3 have anything to do with the solution. Commented Jun 18 at 16:50
• I'm sort of a beginner with op amps, why would'nt they have something to do with the solution? Commented Jun 18 at 16:54
• Because it's a trick question. The circuit is a summing amplifier with the question concerning one of the two inputs.
– Fred
Commented Jun 18 at 16:57
• Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.
– Community Bot
Commented Jun 18 at 17:47
• If you remove the op amp from the circuit, how does that change the circuit equivalence at nodes A & B?
– qrk
Commented Jun 18 at 17:52