Which sequence describes finding a Thevenin equivalent?

• A. Remove load, find R_th by deactivating sources, find V_open-circuit, connect load.
• B. Remove load, find V_open-circuit, find R_th with sources deactivated, connect load.
• C. Replace network by a current source I_th in parallel with R_th, measure short-circuit current.
• D. Assume load is connected and compute total power.

Answer: (B)

Finding a Thevenin equivalent means expressing the network from the load’s perspective as a voltage source Vth in series with a resistance Rth. To get those two numbers correctly, you first determine the open-circuit voltage across the load terminals (with the load removed and the sources in their normal operating state). That voltage is Vth. Then you find the resistance seen from the terminals with all independent sources deactivated (voltage sources shorted, current sources opened); that resistance is Rth. Finally, you reconnect the load to use the Thevenin model.

The described sequence matches this: remove the load, measure the open-circuit voltage across the terminals, then determine Rth with sources deactivated, and then connect the load. This order ensures Vth reflects the actual circuit’s behavior with no load, and Rth reflects the internal resistance as seen by the load when sources are turned off.

Why the other approaches aren’t correct: deactivating sources before measuring open-circuit voltage would give you a different voltage than Vth, because the circuit’s active sources shape that voltage. Replacing the network with a current source in parallel with Rth corresponds to a Norton model, not the direct Thevenin sequence asked for. And computing total power with the load attached doesn’t yield the Thevenin parameters.