After obtaining Thevenin equivalent, how is the load voltage determined with R_th and V_th present?

After obtaining Thevenin equivalent, how is the load voltage determined with R_th and V_th present?

• A. V_load = V_th × (R_load / (R_th + R_load))
• B. V_load = V_th × (R_th / (R_th + R_load))
• C. V_load = V_th
• D. V_load = V_th × (R_th + R_load) / R_load

Answer: (A)

In a Thevenin circuit, the load voltage comes from a voltage divider formed by the Thevenin resistance in series with the load. The current is I = V_th / (R_th + R_load), and the voltage across the load is V_load = I × R_load = V_th × (R_load / (R_th + R_load)). This is why the load sees a fraction of the open-circuit voltage equal to the load resistance divided by the total resistance. If R_load is very large, V_load approaches V_th; if R_load is very small, V_load drops toward zero. The other expressions would represent the voltage across the internal resistance or exceed V_th, which doesn’t describe the load voltage in this setup.

In a Thevenin circuit, the load voltage comes from a voltage divider formed by the Thevenin resistance in series with the load. The current is I = V_th / (R_th + R_load), and the voltage across the load is V_load = I × R_load = V_th × (R_load / (R_th + R_load)). This is why the load sees a fraction of the open-circuit voltage equal to the load resistance divided by the total resistance. If R_load is very large, V_load approaches V_th; if R_load is very small, V_load drops toward zero. The other expressions would represent the voltage across the internal resistance or exceed V_th, which doesn’t describe the load voltage in this setup.