The short-circuit current

This is the circuit from the lecture, running. Change it and the answer changes with it:

• Click any component value to edit it, or drag components to rearrange.
• The wrench opens a step-by-step analysis — it chooses a reference node and writes the node equations. Leave its Domain on the DC operating point for this deck.
• The crosshairs probe reads a node voltage or a branch current, so you can check any intermediate result rather than only the final answer.

Probe the current in the 2 k: 1.2 mA, which is $I_N$. Then note that $V_{oc}/I_{sc} = 6/1.2\text{ mA} = 5\text{ k}\Omega$ — the same $R_{Th}$ the resistor network gave, found without combining a single resistor.